Noise and vibration phenomena play an ever more important role in the functional performance, reliability and lifetime, resource efficiency, safety, comfort, and total cost of ownership of smart products, processes and cyber-physical systems. There is a raising awareness of the impact of noise and vibrations on human health and their pivotal role in the development of a sustainable economy and environment.

The KU Leuven Noise and Vibration research group strives for international leadership in engineering dynamics through excellent research, education and services; building upon an expertise of five decades and with the Digital Twin concept playing a central role in its roadmap. Dynamic behaviour models, validated and enriched with dynamic measurement data, allow for a continuously updated virtual replica of a structure or system. This very powerful concept brings added value in every phase of the product lifecycle. Digital Twins drive the design, analysis and testing phases as well as the manufacturing and assembly in order to achieve the envisaged dynamic performance. Furthermore, Digital Twins

also enable intelligent monitoring and control during the entire operational lifetime of the structure or system to get optimal performance given its actual state and condition and given the planned and anticipated usage and load scenarios at that moment.

Cross-fertilization between strategic basic research, application oriented developments and technology transfer activities is key. Being at the origin of spin-off company LMS International, now Siemens Industry Software, and serving as core group of Flanders Make, the strategic research centre for the manufacturing industry in Flanders, illustrate that industrial and societal relevance are essential drivers, along with multidisciplinary partner-ships and inter-sectorial cooperation. Applications focus on industrial machinery and manufacturing, transportation, energy supply and health care. The organisation of the yearly ISMA and ISAAC courses and the biennial ISMA conference on Noise & Vibration Engineering, and the group’s presence on dedicated digital media, are key dissemination elements, next to top journal publications and presentations at reference conferences and workshops.

Mission and strategy

• EU H2020 Marie Sklodowska Curie IF, WIDEA: Wave-based Inspection for Damage Evaluation in structurally-Advanced composites (coordinator)• EU H2020 Marie Sklodowska Curie ETN, PBNv2: Next generation Pass-By Noise approaches for new powertrain vehicles (coordinator)• EU H2020 Marie Sklodowska Curie ETN, SmartAnswer: Smart mitigation of flow-induced acoustic radiation and transmission for reduced noise• EU H2020 Marie Sklodowska Curie ETN, Acoutect: A sound fundament for our future buildings• EU H2020 CSA, Science2Society: Improving university, industry and society interfaces to boost the throughput capacity of Europe’s innovation stakeholders (coordinator)• COST Action, CA15125, DENORMS: Designs for Noise Reducing Materials and Structures• EU H2020 Marie Sklodowska Curie EJD, VIPER: Vibroacoustics of Periodic media• EU H2020 Marie Sklodowska Curie ETN, ITEAM: Interdisciplinary Training Network in Multi-Actuated Ground Vehicles• EU H2020 Marie Sklodowska Curie ETN, SSeMID: Stability and Sensitivity Methods for Industrial Design• EU FP7 Marie Curie ITN, ANTARES: Advanced Training and Research in Energy Efficient Smart Structures (coordinator)• Flanders Make SBO project JOINTTOOL: Characterisation and modelling of joints• Flanders Make SBO project IMALIGHT: Integration and manufacturability aspects of lightweight structures exploiting inherent dynamic properties• Flanders Make SBO project MOFORM: Model based force measurements• Flanders Make SBO project EMODO: Efficient model based design parameter exploration and optimization in mechatronics• Flanders Make ICON project EVIT: Model-based experimental-virtual testing• Flanders Make ICON project OPTIMULTI: Optimal design of multi-material structures• Flanders Make ICON project MODA: Model based data analytics• Flanders Make ICON project MULTISENSOR: Multi-sensor system design and validation• Flanders Make ICON project CONCEVAL: Multi-attribute concept evaluation of lightweight structures• Flanders Make ICON project Drivetrain_Codesign: Physical and control co-design of electromechanical drivetrains for machines and vehicles• SIM SBO project M3/MOR4MDESIGN: Model order reduction for efficient multi-scale, multi-parameter, multi-attribute and multi-material design• SIM SBO project M3/DETECT-IV: Model-supported development of NDT methods for defect detection in composite parts• SIM SBO project MADUROS/DeMoPreCI-MDT: Development, monitoring and prediction of coupled interactions in material durability testing• SIM IBO project M3/FATAM: Fatigue of additive manufactured components• SIM ICON project M3/DETECTION: Model-supported non-destructive testing for the detection of defects in lightweight structures: an industrial solution• VLAIO O&O project no. 155015 , WERECLEAN: Weight Reduction Cleaning• VLAIO O&O project no. 150958, ENDURANCE: Efficient durability testing and vehicle usage evaluation• IWT O&O project no. 150394, ECO-Powertrain: Innovative NVH testing and simulation methods for eco-efficient powertrain engineering• IWT Baekeland project no. 140768, Model based condition and parameter estimation of the high-dynamic behaviour of mechatronic weaving looms• IWT Baekeland project, Methodology development for use of high-fidelity physical models in couple input/parameter/state estimation of mechatronic systems in aeronautics• FWO doctoral grant strategic basic research 1S24918N, Design and analysis of compact, lightweight material concepts for sound mitigation in flow ducts• FWO doctoral grant strategic basic research 1S39517N, Model Based System Engineering approaches for the identification and monitoring of mechatronic systems• FWO doctoral grant 1106016N, Development of model order reduction techniques for mechatronic system models in inverse problems• FWO doctoral grant 11ZH817N, Design of tuned lightweight metamaterials for broadband sound transmission and sound absorption• FWO postdoctoral grant 12D2614N, Efficient prediction techniques for the design and dynamic analysis of innovative lightweight materials with favourable vibro-acoustic properties• FWO postdoctoral grant 12D1617N, Development of adaptive model order reduction strategies for simulation and state-estimation of mechanical systems

A complete list of current and past research projects is available at www.mech.kuleuven.be/en/research/mod/Projects

Some key numbers of the research group:

Selection of on-going project funding:

• A 6 full time equivalent permanent staff,• 9 postdoctoral researchers,• and 74 PhD researchers, including 27 industrial PhDs.

Head of the group:Wim Desmetwim.desmet@kuleuven.be +32 16 32 25 27

Contact persons:Industrial research contact: Bert Pluymers bert.pluymers@kuleuven.be +32 16 32 25 29

Address:Celestijnenlaan 300 – box 2420 3001 HeverleeBelgium

Number of on-going PhD and postdoc Fellowships (incl. Marie Sklodowska Curie Fellowships)

Number of on-goingresearch projects

6 DOF multi-axial hydraulic shaker table (Team CUBETM)Dedicated LMS TWR software is used to allow accurate reproduction of requested load data or LMS MIMO random control is used to obtain desired power spectral density functions at certain points on the test structure. The shaker table allows normal payloads up to 500 kg, which can go up to 1000 kg for special applications. Test objects can be mounted on the five sides of the CUBE if desired, easing fixturing and replicating actual installation conditions. The displacement, speed and acceleration limits are, resp., a stroke of 101.6mm vertical and 50.8 mm horizontal; a velocity of 0.96 m/s; and an acceleration of 10g with a control bandwidth 0-300Hz.

Quarter car suspension test rigFor the validation of virtual sensing strategies, which aim to identify the loads acting on automotive suspension systems, two test setups have been developed. A first setup consists of a frame where a McPherson suspension system is attached, while the CUBE shaker table, a powerful 6-dof multi axial hydraulic shaker, can apply predefined loads on the wheel side. In a second test setup a twist beam suspension is fixed to a frame while the shaker applies the loads to the wheel.

Accelerated multi-axial fatigue experimentsA novel test setup is developed to subject cylindrical specimens of different sizes and materials to complex real-life loading con-ditions. Bending moments of 5–150 Nm can be combined with torsional moments of 5–200 Nm at test frequencies between 2 and 60 Hz. This significantly reduces the time and cost needed for the experimental validation of analytical and numerical fatigue calculations with respect to conventional fatigue testing techniques.

Flow-acoustic characterisation of duct systemsThis modular facility enables the acoustic characterisation of the transmission characteristics of duct elements of various dimen-sions such as HVAC and exhaust system components,… as well as the indirect determination of the acoustic impedance of sound absorbing wall treatments, both under quiescent conditions and in the presence of a mean flow. A mean flow up to a Mach number of 0.3 can be reached for duct diameters of 50mm with both uniform (Roots blower) and time-pulsating (cold engine simulator) flow fields. The experimental approach is based on an active multiport characterisation of the test objects using multiple flush-mounted pressure transducers and a combined multiple-source/multiple-load approach.

Open circuit aero-acoustic wind tunnelThe open circuit aero-acoustic wind tunnel is used for the aero-acoustic analysis of confined subsonic flow applications and low Mach number free-field applications. Flow visualisation measurements, carried out with stereo PIV (Particle Image Velocimetry), can be combined with acoustic in-duct and far-field pressure methods to characterise aerodynamic noise generation mechanisms and their far-field radiation. Anechoic, isothermal and low-turbulence inflow conditions are ensured by an acoustic labyrinth, a heat exchanger and a flow conditioner. Variable inlet conditions can be imposed using a frequency regulated Roots blower.

Lightweight components dynamic characterisation test rigThis non-standard test rig allows the experimental evaluation of the acoustic insertion loss of lightweight components for both air-borne and structure-borne excitations in a quick and very practical way. It consists of a concrete cavity of less than one cubic meter particularly shaped to ensure a desired distribution of the acoustic natural frequencies in the low frequency region. The front wall can be changed such that it can host test specimen of different sizes and thicknesses. The cavity can also be fully closed for acoustic absorption testing. Vibration levels, Sound Pressure Level, particle velocity and acoustic intensity can be measured over the radiating component in the frequency range [50-10000] Hz. The described system is a powerful tool to characterise and analyse novel materials and optimised lightweight components.

Impedance tubeAn impedance tube for acoustic impedance, reflection and absorption measurements has been developed. The measurement method is the two microphone transfer function method described in the standard ISO 10534-2. The error mechanisms which cause deviations on the reflection measurement have been investigated. A precision measurement head wherein the microphones are positioned has been developed, resulting in superior characteristics compared to the commercially available tubes in terms of accuracy and frequency range. The impedance tube has a diameter of 45mm. For a hard wall measurement, the reflection coefficient deviation with respect to the theoretical value remains within 1% for frequencies ranging from 30Hz until 2kHz.

July 2018

www.mech.kuleuven.be/mod

• Industrial Research Fund Mandate – Dynamics and Mechatronics: oxygen for innovating industry – Bert Pluymers

• LMS Chair on Vehicle Mechatronics – Wim Desmet

• Core lab DMMS (Dynamics of Mechanical and Mechatronic Systems) of Flanders Make (the strategic research centre for the manufacturing industry)

• Spin-offs: LMS International/Siemens Industry Software, DAP/Co-Services, SoundTalks

@KULnoisevib KU Leuven Noise & Vibration Movie Channel

kuleuven.mod

Virtual torque sensing on a mechatronic drivetrainThis test setup is purpose-built for exciting torsional driveline dynamics with minimal influence from the frame or its surroundings. Two 5,5 kW 2-pole induction machines can follow user-defined speed and torque profiles, including fast-transient and four-quadrant operation. One machine can be displaced laterally, such that the double-cardan transmission introduces non-linear torsional dynamics. The latter can also be replaced by other driveline elements. Electrical current and voltage measurements are available, as well as angular displacements, speeds and rotational accelerations. This allows model-based virtual torque sensing in a frequency range of 0–200 Hz. A built–in torque sensor allows quantitative experimental validation.

ElectroPulsTM E10000 Linear systemThe ElectroPulsTM E10000 Linear system is a state-of-the-art, all-electric test instrument designed for dynamic and static testing on a wide range of materials and components. It includes Instron advanced digital control electronics, Dynacell load cell, Console software, and the very latest in testing technology – hassle-free tuning based on specimen stiffness, electrically operated cross-head lifts, a T-slot table for flexible test setups. High dynamic performance, capable of performing up to 100 Hz, with ±10 kN dynamic linear load capacity. Linear stroke of 60mm. It is equipped with an environmental chamber (H 485mm, W 240mm) with advanced temperature control from -100°C to 350°C.

KU Leuven Noise & Vibration Research Group

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

111

20

10

3

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

7 7

151

12

2

International funding agencies

The KU Leuven Noise and Vibration Research Group has a fully equipped noise and vibration laboratory containing:

• data acquisition systems 3 LMS SCADAS III (40(+4) channels in, 6 (+2) channels out), 2 LMS SCADAS mobile (40 channels in, 6 channels out), NI PXI-4472 (32ch), NI DSA4551 (2ch in, 2ch out), NI Crio (16ch)

• sensors: more than 300 accelerometers (mono-axial, tri-axial, lightweight) (PCB), more than 100 microphones (PCB, B&K), 4 impedance heads (PCB), force and pressure transducers, displacement probes, PU probe (Microflown), scanning laser vibrometer (Polytec PSV 500), scanning laser-vibrometer (Ometron), laser vibro-meters for translational and torsional vibrations (Polytec), acoustic intensity probe and analyser (B&K), holographic camera system (Vidispec), laser distance sensors (Baumer), CMM (Krypton K600), Portable Vibration Calibrator (The Modal Shop), LMS Soundbrush, 2 high speed cameras (JAI SP-1200M-CXP4, Ximea XiQ), CAE Noise-Inspector acoustic camera, Neumann KU 100 Dummy Head Microphone, Kistler dynamometers (9119AA1, 9259A, 9265B), strain gauges (PCB, HBM, Vishay), ferraris sensors (Baumer-Huebner ACC74), encoders (Siemens 1XP8032-20)

• exciters: manual and automatic modal impact hammers of different size (Maul-theet, PCB), 12 electromagnetic shakers ranging from 10 to 2500N (The Modal Shop, B&K, MB, Unholtz-Dickie, Link, LDS), miniature inertial shaker (The Modal Shop), 6-DOF hydraulic shaker table (Team – CubeTM), a SmartShaker (The Modal Shop), LMS-Qsources Low-Mid Q-LMF and Mid- High Q-LHF volume sources, multi-loudspeaker simulation and reference sources, INSTRON ElectroPuls E10000 Linear- testing system, Digiducer - 333D01 USB Digital Accelerometer

• signal conditioning equipment: analogue and digital filters, digital signal proces-sors, multi-channel ADC’s, wave synthesizers....

• MIMO adaptive active noise and vibration control systems (dSpace1103, dSpace1104, dSpace1006)

• semi-anechoic measurement room

Experimental facilities Vibro-acoustics Multi-body dynamics

Aero-acoustics

Structural reliability, monitoring and uncertainty

Smart system dynamics

The vibro-acoustic research focusses on the simulation, analysis, monitoring and control of the vibro-acoustic behaviour of mechanical, mechatronic and biomechanical products and processes, as typically encountered in the transportation, the industrial machinery, the energy and the health care sector.

(Parametric) acceleration methods for finite element and boundary element based techniques, isogeometric model-ling, strategies to account for uncertainties and variabilities, and (hybrid) wave based approaches are being developed and validated in view of the efficient simulation over the full audio frequency range. Coupling strategies are explored to allow the efficient and effective integration of vibro- acoustic models into system-level multiphysics models, where disparate length, time and energy scales come together.

High-fidelity models in combination with efficient model reduction schemes are used in time-domain observers in view of virtual sensing strategies to enrich experimental data sets for robust and reliable analysis and validation purposes

Multi-body simulation has become a crucial tool in the design of modern mechatronic systems. In the current trend towards faster, lighter-weight, more energy efficient and reliable machines and processes, flexible mechanism behaviour has to be accounted for. Research focusses on methodological innovations and industrial applications for flexible multi-body system simulation. The developed methodologies range from high-fidelity modelling approaches for a.o. (optimal) design and analysis to real-time models for hardware-in-the-loop, model based condition monitoring, and model embedded control purposes.Employing in-house developed general purpose multi-body toolboxes, methodologies have been designed which allow the efficient high-fidelity simulation of large scale flexible multibody systems. These modelling approaches are leveraged in the context of structural component topology optimisation for improved dynamic system response, lifecycle assessment and system-level model identification. Through the development of dedicated parametric and nonlinear model order reduction techniques, novel approaches to account for detailed gear dynamics behaviour have been developed and successfully deployed in a range of industrial applications. Particular attention is also given to the modelling of key connecting components like bearings and bushings, and experimental identification of their behaviour.Model order reduction and machine learning based approaches are being developed to exploit high-fidelity (flexible) multibody models in a range of real-time and online applications. Through targeted reformulations of the system dynamics, novel model structures can be obtained which allow low-cost models for state-input-parameter estimation in a full-system setting. This enables an effective fusion approach for all available sensor in modern mechatronic machines to generate virtual measurements. Application developments on component level focus predomi-nantly on the impact of contact mechanics on the dynamics of geared transmissions and bearings. System-level validations are being performed on a wide range of applications such as vehicle dynamics performance evaluation, drivetrain dynamics of multi-megawatt wind turbines, high-speed weaving looms, combine harvesters, and operational bearing load assessment in integrated industrial machinery.

The aero-acoustics research focusses on the numerical prediction and experimental validation of aerodynamic noise generation and propagation mechanisms for confined subsonic flows. Particular attention is paid to low Mach- number applications (mufflers, expansion chambers, confined fans, bends, contractions,...), as they are commonly encountered in automotive exhaust systems, HVAC systems, turbomachinery, ... Given the large disparity in length and energy scales between typical aerodynamic noise sources and their associated acoustic propagation waves, hybrid simulation strategies are adopted with particular focus on the acoustic propagation side and the aerodynamic source input. In this respect, focus is put on numerical solution strategies and conservative integration schemes for linearised Euler and Navier-Stokes equations, stochastic turbulence reconstruction approaches, aerodynamic/acoustic splitting procedures and active multi-port modelling. Experimental procedures and dedicated test rigs are developed in view of the active multi-port characterisation of duct systems of industrial complexity, as well as for material characterisation and impedance eduction. Acoustic and aerodynamic measurements, in combination with advanced signal processing and correlation techniques, are developed for far-field acoustic radiation and directivity identification, as well as for aero-acoustic source localisation and source identification. The numerical approaches and experimental tools are being used for the design and analysis of innovative light-weight liner materials for the acoustic treatment of flow confining ducts and walls with optimal acoustic performance.

Uncertainty and variability of mechanical systems is an issue of increasing concern, both in the design phase and in operational conditions. Vibrations are often the cause of non-nominal behaviour or in some cases even structural degradation.

Numerical formalisms and algorithms are developed to deal with non-determinism in analysis and design. After a decade of intensive research on non-probabilistic methods, a fuzzy finite element method is now available for use in conjunction with commercial FE software. In the area of probabilistic methods, an inverse identification strategy is validated to quantify scatter in structural model parameters that uses both experimental data sets and numerical FE models. Recent efforts focus on the identification of spatial scatter and uncertainty using both interval fields and random fields. Generic non-deterministic modelling strategies are applied to modern material families. The spatial nature of uncertainty is strongly pronounced in materials with a non- uniform composition such as fibre reinforced polymer composites, where the tow paths of the fibre reinforcement architecture exhibit geometrical deviations from the nominal lay-out. Another category which is also marked by spatial uncertainty is additive manufactur-ing, where the layer-wise build-up and process parame-ters introduce spatial scatter in material characteristics.

Furthermore, research focusses on the development

The smart system dynamics research focusses on the development, realisation and experimental validation of (physical behaviour) model based approaches supportive to the design, analysis, manufacturing and operational phases of mechanical and mechatronic systems. In short, the research targets the development of Digital Twins of electro-mechan-ical systems, with a focus on their dynamic behaviour, their real-life application and the creation of added value exploiting the Digital Twins in new business models.Core activities involve the development of novel modelling and co-simulation approaches for system level analysis together with appropriate identification strategies; of coupled state-disturbance parameter estimation using moving horizon observers, compressive sensing and extended Kalman filtering with both real-time and online applications for blending simulation data with measurement

and to bring model based (vibro-)acoustic condition monitor-ing strategies towards industrial applications.

Advanced experimental testing and analysis techniques in combination with inverse methods are developed and associated test rigs are designed and implemented for the dynamic characterisation of (multilayer) materials and structures, for source localisation and quantification, for damage detection and for sound synthesis and sound engineering purposes.

An emerging research line focusses on the design, testing and optimisation of light-weight panels and structures with a particular focus on intelligent designs that exhibit vibro-acoustic stop-band behaviour. Multiple physical realisations prove the potential of so-called resonant metamaterials for engineering applications in combining low mass with excellent noise performance or vibration isolation in the low frequency range (http://youtu.be/JUi3qK32mf0 and https://youtu.be/GWHeiEnx4ks).

data; of coupling strategies to embed high-fidelity 3D models in a port-based context; and of design space exploration using variable model complexity representations. A key research line within the above developments combines high-fidelity, time-efficient models with coupled state, input and parameter estimation methods to develop virtual sensors, allowing to measure quantities otherwise difficult or impossible to measure directly. Application examples of this approach are a stress- camera (https://youtu.be/pILsapTeoQU) and a virtual torque sensor (https://youtu.be/9-DbplXC_3M). Other applications are online characterisation of bushing or tyre-parameters and energy flow measurements through machines.Overall target applications are predominantly in the fields of vehicle mechatronics, industrial machinery and intelligent lightweight structures, where the developed technologies allow the generation of new, more accurate, more reliable and/or timely information to boost decision making, control, monitoring, performance, added-value offered, etc.A specific research activity concentrates on the design of mechanisms and control strategies to high-accuracy pointing in small spacecraft and CubeSats, where rolling element bearings and reaction wheels which are mounted in spacecraft are a source of disturbance in systems which are designed to operate in microgravity and conditions of extremely low vibrations.

of data driven and model based condition monitoring methods based mainly on the analysis of vibro-acoustic signals to monitor the performance of complex rotating structures and machines in the operational phase and at system level. With the current trend towards ever lighter and more energy- efficient structural design, another focus area is the analysis of fatigue issues in structural reliability.

Conventional sensors such as accelerometers, micro-phones and arrays, proximity probes, thermocouples and strain gauges are deployed in conjunction with physical behaviour models to monitor changes in the dynamic behaviour focussing on early and accurate damage detection (detection), damage localisation (identification & source separation), damage characterisation & quantification (diagnosis) and estimation of the Remaining Useful Life (prognosis), at the level of an individual unit or at the level of a fleet of units. The diagnostic methods are combined with novel supervised, semi-supervised (anomaly detection) and unsupervised classification methods (SVM, SVDD, Deep Learning) focussing on the reduction of false alarms/missed detections in the frame of a complete diagnostic system. Experimental identification procedures and dedicated test rigs are used to characterise structural degradation mechanisms on individual components such as bearings and gears. Recent applications include agricultural harvesting machines, trains, large wind turbines, diesel engines and electro-mechanical drivetrains.

The KU Leuven Noise and Vibration Research Group has a fully equipped noise and vibration laboratory containing:

• data acquisition systems 3 LMS SCADAS III (40(+4) channels in, 6 (+2) channels out), 2 LMS SCADAS mobile (40 channels in, 6 channels out), NI PXI-4472 (32ch), NI DSA4551 (2ch in, 2ch out), NI Crio (16ch)

• sensors: more than 300 accelerometers (mono-axial, tri-axial, lightweight) (PCB), more than 100 microphones (PCB, B&K), 4 impedance heads (PCB), force and pressure transducers, displacement probes, PU probe (Microflown), scanning laser vibrometer (Polytec PSV 500), scanning laser-vibrometer (Ometron), laser vibro-meters for translational and torsional vibrations (Polytec), acoustic intensity probe and analyser (B&K), holographic camera system (Vidispec), laser distance sensors (Baumer), CMM (Krypton K600), Portable Vibration Calibrator (The Modal Shop), LMS Soundbrush, 2 high speed cameras (JAI SP-1200M-CXP4, Ximea XiQ), CAE Noise-Inspector acoustic camera, Neumann KU 100 Dummy Head Microphone, Kistler dynamometers (9119AA1, 9259A, 9265B), strain gauges (PCB, HBM, Vishay), ferraris sensors (Baumer-Huebner ACC74), encoders (Siemens 1XP8032-20)

• exciters: manual and automatic modal impact hammers of different size (Maul-theet, PCB), 12 electromagnetic shakers ranging from 10 to 2500N (The Modal Shop, B&K, MB, Unholtz-Dickie, Link, LDS), miniature inertial shaker (The Modal Shop), 6-DOF hydraulic shaker table (Team – CubeTM), a SmartShaker (The Modal Shop), LMS-Qsources Low-Mid Q-LMF and Mid- High Q-LHF volume sources, multi-loudspeaker simulation and reference sources, INSTRON ElectroPuls E10000 Linear- testing system, Digiducer - 333D01 USB Digital Accelerometer

• signal conditioning equipment: analogue and digital filters, digital signal proces-sors, multi-channel ADC’s, wave synthesizers....

• MIMO adaptive active noise and vibration control systems (dSpace1103, dSpace1104, dSpace1006)

• semi-anechoic measurement room

Experimental facilities Vibro-acoustics Multi-body dynamics

Aero-acoustics

Structural reliability, monitoring and uncertainty

Smart system dynamics

The vibro-acoustic research focusses on the simulation, analysis, monitoring and control of the vibro-acoustic behaviour of mechanical, mechatronic and biomechanical products and processes, as typically encountered in the transportation, the industrial machinery, the energy and the health care sector.

(Parametric) acceleration methods for finite element and boundary element based techniques, isogeometric model-ling, strategies to account for uncertainties and variabilities, and (hybrid) wave based approaches are being developed and validated in view of the efficient simulation over the full audio frequency range. Coupling strategies are explored to allow the efficient and effective integration of vibro- acoustic models into system-level multiphysics models, where disparate length, time and energy scales come together.

High-fidelity models in combination with efficient model reduction schemes are used in time-domain observers in view of virtual sensing strategies to enrich experimental data sets for robust and reliable analysis and validation purposes

Multi-body simulation has become a crucial tool in the design of modern mechatronic systems. In the current trend towards faster, lighter-weight, more energy efficient and reliable machines and processes, flexible mechanism behaviour has to be accounted for. Research focusses on methodological innovations and industrial applications for flexible multi-body system simulation. The developed methodologies range from high-fidelity modelling approaches for a.o. (optimal) design and analysis to real-time models for hardware-in-the-loop, model based condition monitoring, and model embedded control purposes.Employing in-house developed general purpose multi-body toolboxes, methodologies have been designed which allow the efficient high-fidelity simulation of large scale flexible multibody systems. These modelling approaches are leveraged in the context of structural component topology optimisation for improved dynamic system response, lifecycle assessment and system-level model identification. Through the development of dedicated parametric and nonlinear model order reduction techniques, novel approaches to account for detailed gear dynamics behaviour have been developed and successfully deployed in a range of industrial applications. Particular attention is also given to the modelling of key connecting components like bearings and bushings, and experimental identification of their behaviour.Model order reduction and machine learning based approaches are being developed to exploit high-fidelity (flexible) multibody models in a range of real-time and online applications. Through targeted reformulations of the system dynamics, novel model structures can be obtained which allow low-cost models for state-input-parameter estimation in a full-system setting. This enables an effective fusion approach for all available sensor in modern mechatronic machines to generate virtual measurements. Application developments on component level focus predomi-nantly on the impact of contact mechanics on the dynamics of geared transmissions and bearings. System-level validations are being performed on a wide range of applications such as vehicle dynamics performance evaluation, drivetrain dynamics of multi-megawatt wind turbines, high-speed weaving looms, combine harvesters, and operational bearing load assessment in integrated industrial machinery.

The aero-acoustics research focusses on the numerical prediction and experimental validation of aerodynamic noise generation and propagation mechanisms for confined subsonic flows. Particular attention is paid to low Mach- number applications (mufflers, expansion chambers, confined fans, bends, contractions,...), as they are commonly encountered in automotive exhaust systems, HVAC systems, turbomachinery, ... Given the large disparity in length and energy scales between typical aerodynamic noise sources and their associated acoustic propagation waves, hybrid simulation strategies are adopted with particular focus on the acoustic propagation side and the aerodynamic source input. In this respect, focus is put on numerical solution strategies and conservative integration schemes for linearised Euler and Navier-Stokes equations, stochastic turbulence reconstruction approaches, aerodynamic/acoustic splitting procedures and active multi-port modelling. Experimental procedures and dedicated test rigs are developed in view of the active multi-port characterisation of duct systems of industrial complexity, as well as for material characterisation and impedance eduction. Acoustic and aerodynamic measurements, in combination with advanced signal processing and correlation techniques, are developed for far-field acoustic radiation and directivity identification, as well as for aero-acoustic source localisation and source identification. The numerical approaches and experimental tools are being used for the design and analysis of innovative light-weight liner materials for the acoustic treatment of flow confining ducts and walls with optimal acoustic performance.

Uncertainty and variability of mechanical systems is an issue of increasing concern, both in the design phase and in operational conditions. Vibrations are often the cause of non-nominal behaviour or in some cases even structural degradation.

Numerical formalisms and algorithms are developed to deal with non-determinism in analysis and design. After a decade of intensive research on non-probabilistic methods, a fuzzy finite element method is now available for use in conjunction with commercial FE software. In the area of probabilistic methods, an inverse identification strategy is validated to quantify scatter in structural model parameters that uses both experimental data sets and numerical FE models. Recent efforts focus on the identification of spatial scatter and uncertainty using both interval fields and random fields. Generic non-deterministic modelling strategies are applied to modern material families. The spatial nature of uncertainty is strongly pronounced in materials with a non- uniform composition such as fibre reinforced polymer composites, where the tow paths of the fibre reinforcement architecture exhibit geometrical deviations from the nominal lay-out. Another category which is also marked by spatial uncertainty is additive manufactur-ing, where the layer-wise build-up and process parame-ters introduce spatial scatter in material characteristics.

Furthermore, research focusses on the development

The smart system dynamics research focusses on the development, realisation and experimental validation of (physical behaviour) model based approaches supportive to the design, analysis, manufacturing and operational phases of mechanical and mechatronic systems. In short, the research targets the development of Digital Twins of electro-mechan-ical systems, with a focus on their dynamic behaviour, their real-life application and the creation of added value exploiting the Digital Twins in new business models.Core activities involve the development of novel modelling and co-simulation approaches for system level analysis together with appropriate identification strategies; of coupled state-disturbance parameter estimation using moving horizon observers, compressive sensing and extended Kalman filtering with both real-time and online applications for blending simulation data with measurement

and to bring model based (vibro-)acoustic condition monitor-ing strategies towards industrial applications.

Advanced experimental testing and analysis techniques in combination with inverse methods are developed and associated test rigs are designed and implemented for the dynamic characterisation of (multilayer) materials and structures, for source localisation and quantification, for damage detection and for sound synthesis and sound engineering purposes.

An emerging research line focusses on the design, testing and optimisation of light-weight panels and structures with a particular focus on intelligent designs that exhibit vibro-acoustic stop-band behaviour. Multiple physical realisations prove the potential of so-called resonant metamaterials for engineering applications in combining low mass with excellent noise performance or vibration isolation in the low frequency range (http://youtu.be/JUi3qK32mf0 and https://youtu.be/GWHeiEnx4ks).

data; of coupling strategies to embed high-fidelity 3D models in a port-based context; and of design space exploration using variable model complexity representations. A key research line within the above developments combines high-fidelity, time-efficient models with coupled state, input and parameter estimation methods to develop virtual sensors, allowing to measure quantities otherwise difficult or impossible to measure directly. Application examples of this approach are a stress- camera (https://youtu.be/pILsapTeoQU) and a virtual torque sensor (https://youtu.be/9-DbplXC_3M). Other applications are online characterisation of bushing or tyre-parameters and energy flow measurements through machines.Overall target applications are predominantly in the fields of vehicle mechatronics, industrial machinery and intelligent lightweight structures, where the developed technologies allow the generation of new, more accurate, more reliable and/or timely information to boost decision making, control, monitoring, performance, added-value offered, etc.A specific research activity concentrates on the design of mechanisms and control strategies to high-accuracy pointing in small spacecraft and CubeSats, where rolling element bearings and reaction wheels which are mounted in spacecraft are a source of disturbance in systems which are designed to operate in microgravity and conditions of extremely low vibrations.

of data driven and model based condition monitoring methods based mainly on the analysis of vibro-acoustic signals to monitor the performance of complex rotating structures and machines in the operational phase and at system level. With the current trend towards ever lighter and more energy- efficient structural design, another focus area is the analysis of fatigue issues in structural reliability.

Conventional sensors such as accelerometers, micro-phones and arrays, proximity probes, thermocouples and strain gauges are deployed in conjunction with physical behaviour models to monitor changes in the dynamic behaviour focussing on early and accurate damage detection (detection), damage localisation (identification & source separation), damage characterisation & quantification (diagnosis) and estimation of the Remaining Useful Life (prognosis), at the level of an individual unit or at the level of a fleet of units. The diagnostic methods are combined with novel supervised, semi-supervised (anomaly detection) and unsupervised classification methods (SVM, SVDD, Deep Learning) focussing on the reduction of false alarms/missed detections in the frame of a complete diagnostic system. Experimental identification procedures and dedicated test rigs are used to characterise structural degradation mechanisms on individual components such as bearings and gears. Recent applications include agricultural harvesting machines, trains, large wind turbines, diesel engines and electro-mechanical drivetrains.

The KU Leuven Noise and Vibration Research Group has a fully equipped noise and vibration laboratory containing:

• data acquisition systems 3 LMS SCADAS III (40(+4) channels in, 6 (+2) channels out), 2 LMS SCADAS mobile (40 channels in, 6 channels out), NI PXI-4472 (32ch), NI DSA4551 (2ch in, 2ch out), NI Crio (16ch)

• sensors: more than 300 accelerometers (mono-axial, tri-axial, lightweight) (PCB), more than 100 microphones (PCB, B&K), 4 impedance heads (PCB), force and pressure transducers, displacement probes, PU probe (Microflown), scanning laser vibrometer (Polytec PSV 500), scanning laser-vibrometer (Ometron), laser vibro-meters for translational and torsional vibrations (Polytec), acoustic intensity probe and analyser (B&K), holographic camera system (Vidispec), laser distance sensors (Baumer), CMM (Krypton K600), Portable Vibration Calibrator (The Modal Shop), LMS Soundbrush, 2 high speed cameras (JAI SP-1200M-CXP4, Ximea XiQ), CAE Noise-Inspector acoustic camera, Neumann KU 100 Dummy Head Microphone, Kistler dynamometers (9119AA1, 9259A, 9265B), strain gauges (PCB, HBM, Vishay), ferraris sensors (Baumer-Huebner ACC74), encoders (Siemens 1XP8032-20)

• exciters: manual and automatic modal impact hammers of different size (Maul-theet, PCB), 12 electromagnetic shakers ranging from 10 to 2500N (The Modal Shop, B&K, MB, Unholtz-Dickie, Link, LDS), miniature inertial shaker (The Modal Shop), 6-DOF hydraulic shaker table (Team – CubeTM), a SmartShaker (The Modal Shop), LMS-Qsources Low-Mid Q-LMF and Mid- High Q-LHF volume sources, multi-loudspeaker simulation and reference sources, INSTRON ElectroPuls E10000 Linear- testing system, Digiducer - 333D01 USB Digital Accelerometer

• signal conditioning equipment: analogue and digital filters, digital signal proces-sors, multi-channel ADC’s, wave synthesizers....

• MIMO adaptive active noise and vibration control systems (dSpace1103, dSpace1104, dSpace1006)

• semi-anechoic measurement room

Experimental facilities Vibro-acoustics Multi-body dynamics

Aero-acoustics

Structural reliability, monitoring and uncertainty

Smart system dynamics

The vibro-acoustic research focusses on the simulation, analysis, monitoring and control of the vibro-acoustic behaviour of mechanical, mechatronic and biomechanical products and processes, as typically encountered in the transportation, the industrial machinery, the energy and the health care sector.

(Parametric) acceleration methods for finite element and boundary element based techniques, isogeometric model-ling, strategies to account for uncertainties and variabilities, and (hybrid) wave based approaches are being developed and validated in view of the efficient simulation over the full audio frequency range. Coupling strategies are explored to allow the efficient and effective integration of vibro- acoustic models into system-level multiphysics models, where disparate length, time and energy scales come together.

High-fidelity models in combination with efficient model reduction schemes are used in time-domain observers in view of virtual sensing strategies to enrich experimental data sets for robust and reliable analysis and validation purposes

Multi-body simulation has become a crucial tool in the design of modern mechatronic systems. In the current trend towards faster, lighter-weight, more energy efficient and reliable machines and processes, flexible mechanism behaviour has to be accounted for. Research focusses on methodological innovations and industrial applications for flexible multi-body system simulation. The developed methodologies range from high-fidelity modelling approaches for a.o. (optimal) design and analysis to real-time models for hardware-in-the-loop, model based condition monitoring, and model embedded control purposes.Employing in-house developed general purpose multi-body toolboxes, methodologies have been designed which allow the efficient high-fidelity simulation of large scale flexible multibody systems. These modelling approaches are leveraged in the context of structural component topology optimisation for improved dynamic system response, lifecycle assessment and system-level model identification. Through the development of dedicated parametric and nonlinear model order reduction techniques, novel approaches to account for detailed gear dynamics behaviour have been developed and successfully deployed in a range of industrial applications. Particular attention is also given to the modelling of key connecting components like bearings and bushings, and experimental identification of their behaviour.Model order reduction and machine learning based approaches are being developed to exploit high-fidelity (flexible) multibody models in a range of real-time and online applications. Through targeted reformulations of the system dynamics, novel model structures can be obtained which allow low-cost models for state-input-parameter estimation in a full-system setting. This enables an effective fusion approach for all available sensor in modern mechatronic machines to generate virtual measurements. Application developments on component level focus predomi-nantly on the impact of contact mechanics on the dynamics of geared transmissions and bearings. System-level validations are being performed on a wide range of applications such as vehicle dynamics performance evaluation, drivetrain dynamics of multi-megawatt wind turbines, high-speed weaving looms, combine harvesters, and operational bearing load assessment in integrated industrial machinery.

The aero-acoustics research focusses on the numerical prediction and experimental validation of aerodynamic noise generation and propagation mechanisms for confined subsonic flows. Particular attention is paid to low Mach- number applications (mufflers, expansion chambers, confined fans, bends, contractions,...), as they are commonly encountered in automotive exhaust systems, HVAC systems, turbomachinery, ... Given the large disparity in length and energy scales between typical aerodynamic noise sources and their associated acoustic propagation waves, hybrid simulation strategies are adopted with particular focus on the acoustic propagation side and the aerodynamic source input. In this respect, focus is put on numerical solution strategies and conservative integration schemes for linearised Euler and Navier-Stokes equations, stochastic turbulence reconstruction approaches, aerodynamic/acoustic splitting procedures and active multi-port modelling. Experimental procedures and dedicated test rigs are developed in view of the active multi-port characterisation of duct systems of industrial complexity, as well as for material characterisation and impedance eduction. Acoustic and aerodynamic measurements, in combination with advanced signal processing and correlation techniques, are developed for far-field acoustic radiation and directivity identification, as well as for aero-acoustic source localisation and source identification. The numerical approaches and experimental tools are being used for the design and analysis of innovative light-weight liner materials for the acoustic treatment of flow confining ducts and walls with optimal acoustic performance.

Uncertainty and variability of mechanical systems is an issue of increasing concern, both in the design phase and in operational conditions. Vibrations are often the cause of non-nominal behaviour or in some cases even structural degradation.

Numerical formalisms and algorithms are developed to deal with non-determinism in analysis and design. After a decade of intensive research on non-probabilistic methods, a fuzzy finite element method is now available for use in conjunction with commercial FE software. In the area of probabilistic methods, an inverse identification strategy is validated to quantify scatter in structural model parameters that uses both experimental data sets and numerical FE models. Recent efforts focus on the identification of spatial scatter and uncertainty using both interval fields and random fields. Generic non-deterministic modelling strategies are applied to modern material families. The spatial nature of uncertainty is strongly pronounced in materials with a non- uniform composition such as fibre reinforced polymer composites, where the tow paths of the fibre reinforcement architecture exhibit geometrical deviations from the nominal lay-out. Another category which is also marked by spatial uncertainty is additive manufactur-ing, where the layer-wise build-up and process parame-ters introduce spatial scatter in material characteristics.

Furthermore, research focusses on the development

The smart system dynamics research focusses on the development, realisation and experimental validation of (physical behaviour) model based approaches supportive to the design, analysis, manufacturing and operational phases of mechanical and mechatronic systems. In short, the research targets the development of Digital Twins of electro-mechan-ical systems, with a focus on their dynamic behaviour, their real-life application and the creation of added value exploiting the Digital Twins in new business models.Core activities involve the development of novel modelling and co-simulation approaches for system level analysis together with appropriate identification strategies; of coupled state-disturbance parameter estimation using moving horizon observers, compressive sensing and extended Kalman filtering with both real-time and online applications for blending simulation data with measurement

and to bring model based (vibro-)acoustic condition monitor-ing strategies towards industrial applications.

Advanced experimental testing and analysis techniques in combination with inverse methods are developed and associated test rigs are designed and implemented for the dynamic characterisation of (multilayer) materials and structures, for source localisation and quantification, for damage detection and for sound synthesis and sound engineering purposes.

An emerging research line focusses on the design, testing and optimisation of light-weight panels and structures with a particular focus on intelligent designs that exhibit vibro-acoustic stop-band behaviour. Multiple physical realisations prove the potential of so-called resonant metamaterials for engineering applications in combining low mass with excellent noise performance or vibration isolation in the low frequency range (http://youtu.be/JUi3qK32mf0 and https://youtu.be/GWHeiEnx4ks).

data; of coupling strategies to embed high-fidelity 3D models in a port-based context; and of design space exploration using variable model complexity representations. A key research line within the above developments combines high-fidelity, time-efficient models with coupled state, input and parameter estimation methods to develop virtual sensors, allowing to measure quantities otherwise difficult or impossible to measure directly. Application examples of this approach are a stress- camera (https://youtu.be/pILsapTeoQU) and a virtual torque sensor (https://youtu.be/9-DbplXC_3M). Other applications are online characterisation of bushing or tyre-parameters and energy flow measurements through machines.Overall target applications are predominantly in the fields of vehicle mechatronics, industrial machinery and intelligent lightweight structures, where the developed technologies allow the generation of new, more accurate, more reliable and/or timely information to boost decision making, control, monitoring, performance, added-value offered, etc.A specific research activity concentrates on the design of mechanisms and control strategies to high-accuracy pointing in small spacecraft and CubeSats, where rolling element bearings and reaction wheels which are mounted in spacecraft are a source of disturbance in systems which are designed to operate in microgravity and conditions of extremely low vibrations.

of data driven and model based condition monitoring methods based mainly on the analysis of vibro-acoustic signals to monitor the performance of complex rotating structures and machines in the operational phase and at system level. With the current trend towards ever lighter and more energy- efficient structural design, another focus area is the analysis of fatigue issues in structural reliability.

Conventional sensors such as accelerometers, micro-phones and arrays, proximity probes, thermocouples and strain gauges are deployed in conjunction with physical behaviour models to monitor changes in the dynamic behaviour focussing on early and accurate damage detection (detection), damage localisation (identification & source separation), damage characterisation & quantification (diagnosis) and estimation of the Remaining Useful Life (prognosis), at the level of an individual unit or at the level of a fleet of units. The diagnostic methods are combined with novel supervised, semi-supervised (anomaly detection) and unsupervised classification methods (SVM, SVDD, Deep Learning) focussing on the reduction of false alarms/missed detections in the frame of a complete diagnostic system. Experimental identification procedures and dedicated test rigs are used to characterise structural degradation mechanisms on individual components such as bearings and gears. Recent applications include agricultural harvesting machines, trains, large wind turbines, diesel engines and electro-mechanical drivetrains.

Noise and vibration phenomena play an ever more important role in the functional performance, reliability and lifetime, resource efficiency, safety, comfort, and total cost of ownership of smart products, processes and cyber-physical systems. There is a raising awareness of the impact of noise and vibrations on human health and their pivotal role in the development of a sustainable economy and environment.

The KU Leuven Noise and Vibration research group strives for international leadership in engineering dynamics through excellent research, education and services; building upon an expertise of five decades and with the Digital Twin concept playing a central role in its roadmap. Dynamic behaviour models, validated and enriched with dynamic measurement data, allow for a continuously updated virtual replica of a structure or system. This very powerful concept brings added value in every phase of the product lifecycle. Digital Twins drive the design, analysis and testing phases as well as the manufacturing and assembly in order to achieve the envisaged dynamic performance. Furthermore, Digital Twins

also enable intelligent monitoring and control during the entire operational lifetime of the structure or system to get optimal performance given its actual state and condition and given the planned and anticipated usage and load scenarios at that moment.

Cross-fertilization between strategic basic research, application oriented developments and technology transfer activities is key. Being at the origin of spin-off company LMS International, now Siemens Industry Software, and serving as core group of Flanders Make, the strategic research centre for the manufacturing industry in Flanders, illustrate that industrial and societal relevance are essential drivers, along with multidisciplinary partner-ships and inter-sectorial cooperation. Applications focus on industrial machinery and manufacturing, transportation, energy supply and health care. The organisation of the yearly ISMA and ISAAC courses and the biennial ISMA conference on Noise & Vibration Engineering, and the group’s presence on dedicated digital media, are key dissemination elements, next to top journal publications and presentations at reference conferences and workshops.

Mission and strategy

• EU H2020 Marie Sklodowska Curie IF, WIDEA: Wave-based Inspection for Damage Evaluation in structurally-Advanced composites (coordinator)• EU H2020 Marie Sklodowska Curie ETN, PBNv2: Next generation Pass-By Noise approaches for new powertrain vehicles (coordinator)• EU H2020 Marie Sklodowska Curie ETN, SmartAnswer: Smart mitigation of flow-induced acoustic radiation and transmission for reduced noise• EU H2020 Marie Sklodowska Curie ETN, Acoutect: A sound fundament for our future buildings• EU H2020 CSA, Science2Society: Improving university, industry and society interfaces to boost the throughput capacity of Europe’s innovation stakeholders (coordinator)• COST Action, CA15125, DENORMS: Designs for Noise Reducing Materials and Structures• EU H2020 Marie Sklodowska Curie EJD, VIPER: Vibroacoustics of Periodic media• EU H2020 Marie Sklodowska Curie ETN, ITEAM: Interdisciplinary Training Network in Multi-Actuated Ground Vehicles• EU H2020 Marie Sklodowska Curie ETN, SSeMID: Stability and Sensitivity Methods for Industrial Design• EU FP7 Marie Curie ITN, ANTARES: Advanced Training and Research in Energy Efficient Smart Structures (coordinator)• Flanders Make SBO project JOINTTOOL: Characterisation and modelling of joints• Flanders Make SBO project IMALIGHT: Integration and manufacturability aspects of lightweight structures exploiting inherent dynamic properties• Flanders Make SBO project MOFORM: Model based force measurements• Flanders Make SBO project EMODO: Efficient model based design parameter exploration and optimization in mechatronics• Flanders Make ICON project EVIT: Model-based experimental-virtual testing• Flanders Make ICON project OPTIMULTI: Optimal design of multi-material structures• Flanders Make ICON project MODA: Model based data analytics• Flanders Make ICON project MULTISENSOR: Multi-sensor system design and validation• Flanders Make ICON project CONCEVAL: Multi-attribute concept evaluation of lightweight structures• Flanders Make ICON project Drivetrain_Codesign: Physical and control co-design of electromechanical drivetrains for machines and vehicles• SIM SBO project M3/MOR4MDESIGN: Model order reduction for efficient multi-scale, multi-parameter, multi-attribute and multi-material design• SIM SBO project M3/DETECT-IV: Model-supported development of NDT methods for defect detection in composite parts• SIM SBO project MADUROS/DeMoPreCI-MDT: Development, monitoring and prediction of coupled interactions in material durability testing• SIM IBO project M3/FATAM: Fatigue of additive manufactured components• SIM ICON project M3/DETECTION: Model-supported non-destructive testing for the detection of defects in lightweight structures: an industrial solution• VLAIO O&O project no. 155015 , WERECLEAN: Weight Reduction Cleaning• VLAIO O&O project no. 150958, ENDURANCE: Efficient durability testing and vehicle usage evaluation• IWT O&O project no. 150394, ECO-Powertrain: Innovative NVH testing and simulation methods for eco-efficient powertrain engineering• IWT Baekeland project no. 140768, Model based condition and parameter estimation of the high-dynamic behaviour of mechatronic weaving looms• IWT Baekeland project, Methodology development for use of high-fidelity physical models in couple input/parameter/state estimation of mechatronic systems in aeronautics• FWO doctoral grant strategic basic research 1S24918N, Design and analysis of compact, lightweight material concepts for sound mitigation in flow ducts• FWO doctoral grant strategic basic research 1S39517N, Model Based System Engineering approaches for the identification and monitoring of mechatronic systems• FWO doctoral grant 1106016N, Development of model order reduction techniques for mechatronic system models in inverse problems• FWO doctoral grant 11ZH817N, Design of tuned lightweight metamaterials for broadband sound transmission and sound absorption• FWO postdoctoral grant 12D2614N, Efficient prediction techniques for the design and dynamic analysis of innovative lightweight materials with favourable vibro-acoustic properties• FWO postdoctoral grant 12D1617N, Development of adaptive model order reduction strategies for simulation and state-estimation of mechanical systems

A complete list of current and past research projects is available at www.mech.kuleuven.be/en/research/mod/Projects

Some key numbers of the research group:

Selection of on-going project funding:

• A 6 full time equivalent permanent staff,• 9 postdoctoral researchers,• and 74 PhD researchers, including 27 industrial PhDs.

Head of the group:Wim Desmetwim.desmet@kuleuven.be +32 16 32 25 27

Contact persons:Industrial research contact: Bert Pluymers bert.pluymers@kuleuven.be +32 16 32 25 29

Address:Celestijnenlaan 300 – box 2420 3001 HeverleeBelgium

Number of on-going PhD and postdoc Fellowships (incl. Marie Sklodowska Curie Fellowships)

Number of on-goingresearch projects

6 DOF multi-axial hydraulic shaker table (Team CUBETM)Dedicated LMS TWR software is used to allow accurate reproduction of requested load data or LMS MIMO random control is used to obtain desired power spectral density functions at certain points on the test structure. The shaker table allows normal payloads up to 500 kg, which can go up to 1000 kg for special applications. Test objects can be mounted on the five sides of the CUBE if desired, easing fixturing and replicating actual installation conditions. The displacement, speed and acceleration limits are, resp., a stroke of 101.6mm vertical and 50.8 mm horizontal; a velocity of 0.96 m/s; and an acceleration of 10g with a control bandwidth 0-300Hz.

Quarter car suspension test rigFor the validation of virtual sensing strategies, which aim to identify the loads acting on automotive suspension systems, two test setups have been developed. A first setup consists of a frame where a McPherson suspension system is attached, while the CUBE shaker table, a powerful 6-dof multi axial hydraulic shaker, can apply predefined loads on the wheel side. In a second test setup a twist beam suspension is fixed to a frame while the shaker applies the loads to the wheel.

Accelerated multi-axial fatigue experimentsA novel test setup is developed to subject cylindrical specimens of different sizes and materials to complex real-life loading con-ditions. Bending moments of 5–150 Nm can be combined with torsional moments of 5–200 Nm at test frequencies between 2 and 60 Hz. This significantly reduces the time and cost needed for the experimental validation of analytical and numerical fatigue calculations with respect to conventional fatigue testing techniques.

Flow-acoustic characterisation of duct systemsThis modular facility enables the acoustic characterisation of the transmission characteristics of duct elements of various dimen-sions such as HVAC and exhaust system components,… as well as the indirect determination of the acoustic impedance of sound absorbing wall treatments, both under quiescent conditions and in the presence of a mean flow. A mean flow up to a Mach number of 0.3 can be reached for duct diameters of 50mm with both uniform (Roots blower) and time-pulsating (cold engine simulator) flow fields. The experimental approach is based on an active multiport characterisation of the test objects using multiple flush-mounted pressure transducers and a combined multiple-source/multiple-load approach.

Open circuit aero-acoustic wind tunnelThe open circuit aero-acoustic wind tunnel is used for the aero-acoustic analysis of confined subsonic flow applications and low Mach number free-field applications. Flow visualisation measurements, carried out with stereo PIV (Particle Image Velocimetry), can be combined with acoustic in-duct and far-field pressure methods to characterise aerodynamic noise generation mechanisms and their far-field radiation. Anechoic, isothermal and low-turbulence inflow conditions are ensured by an acoustic labyrinth, a heat exchanger and a flow conditioner. Variable inlet conditions can be imposed using a frequency regulated Roots blower.

Lightweight components dynamic characterisation test rigThis non-standard test rig allows the experimental evaluation of the acoustic insertion loss of lightweight components for both air-borne and structure-borne excitations in a quick and very practical way. It consists of a concrete cavity of less than one cubic meter particularly shaped to ensure a desired distribution of the acoustic natural frequencies in the low frequency region. The front wall can be changed such that it can host test specimen of different sizes and thicknesses. The cavity can also be fully closed for acoustic absorption testing. Vibration levels, Sound Pressure Level, particle velocity and acoustic intensity can be measured over the radiating component in the frequency range [50-10000] Hz. The described system is a powerful tool to characterise and analyse novel materials and optimised lightweight components.

Impedance tubeAn impedance tube for acoustic impedance, reflection and absorption measurements has been developed. The measurement method is the two microphone transfer function method described in the standard ISO 10534-2. The error mechanisms which cause deviations on the reflection measurement have been investigated. A precision measurement head wherein the microphones are positioned has been developed, resulting in superior characteristics compared to the commercially available tubes in terms of accuracy and frequency range. The impedance tube has a diameter of 45mm. For a hard wall measurement, the reflection coefficient deviation with respect to the theoretical value remains within 1% for frequencies ranging from 30Hz until 2kHz.

July 2018

www.mech.kuleuven.be/mod

• Industrial Research Fund Mandate – Dynamics and Mechatronics: oxygen for innovating industry – Bert Pluymers

• LMS Chair on Vehicle Mechatronics – Wim Desmet

• Core lab DMMS (Dynamics of Mechanical and Mechatronic Systems) of Flanders Make (the strategic research centre for the manufacturing industry)

• Spin-offs: LMS International/Siemens Industry Software, DAP/Co-Services, SoundTalks

@KULnoisevib KU Leuven Noise & Vibration Movie Channel

kuleuven.mod

Virtual torque sensing on a mechatronic drivetrainThis test setup is purpose-built for exciting torsional driveline dynamics with minimal influence from the frame or its surroundings. Two 5,5 kW 2-pole induction machines can follow user-defined speed and torque profiles, including fast-transient and four-quadrant operation. One machine can be displaced laterally, such that the double-cardan transmission introduces non-linear torsional dynamics. The latter can also be replaced by other driveline elements. Electrical current and voltage measurements are available, as well as angular displacements, speeds and rotational accelerations. This allows model-based virtual torque sensing in a frequency range of 0–200 Hz. A built–in torque sensor allows quantitative experimental validation.

ElectroPulsTM E10000 Linear systemThe ElectroPulsTM E10000 Linear system is a state-of-the-art, all-electric test instrument designed for dynamic and static testing on a wide range of materials and components. It includes Instron advanced digital control electronics, Dynacell load cell, Console software, and the very latest in testing technology – hassle-free tuning based on specimen stiffness, electrically operated cross-head lifts, a T-slot table for flexible test setups. High dynamic performance, capable of performing up to 100 Hz, with ±10 kN dynamic linear load capacity. Linear stroke of 60mm. It is equipped with an environmental chamber (H 485mm, W 240mm) with advanced temperature control from -100°C to 350°C.

KU Leuven Noise & Vibration Research Group

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

111

20

10

3

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

7 7

151

12

2

International funding agencies

Noise and vibration phenomena play an ever more important role in the functional performance, reliability and lifetime, resource efficiency, safety, comfort, and total cost of ownership of smart products, processes and cyber-physical systems. There is a raising awareness of the impact of noise and vibrations on human health and their pivotal role in the development of a sustainable economy and environment.

The KU Leuven Noise and Vibration research group strives for international leadership in engineering dynamics through excellent research, education and services; building upon an expertise of five decades and with the Digital Twin concept playing a central role in its roadmap. Dynamic behaviour models, validated and enriched with dynamic measurement data, allow for a continuously updated virtual replica of a structure or system. This very powerful concept brings added value in every phase of the product lifecycle. Digital Twins drive the design, analysis and testing phases as well as the manufacturing and assembly in order to achieve the envisaged dynamic performance. Furthermore, Digital Twins

also enable intelligent monitoring and control during the entire operational lifetime of the structure or system to get optimal performance given its actual state and condition and given the planned and anticipated usage and load scenarios at that moment.

Cross-fertilization between strategic basic research, application oriented developments and technology transfer activities is key. Being at the origin of spin-off company LMS International, now Siemens Industry Software, and serving as core group of Flanders Make, the strategic research centre for the manufacturing industry in Flanders, illustrate that industrial and societal relevance are essential drivers, along with multidisciplinary partner-ships and inter-sectorial cooperation. Applications focus on industrial machinery and manufacturing, transportation, energy supply and health care. The organisation of the yearly ISMA and ISAAC courses and the biennial ISMA conference on Noise & Vibration Engineering, and the group’s presence on dedicated digital media, are key dissemination elements, next to top journal publications and presentations at reference conferences and workshops.

Mission and strategy

• EU H2020 Marie Sklodowska Curie IF, WIDEA: Wave-based Inspection for Damage Evaluation in structurally-Advanced composites (coordinator)• EU H2020 Marie Sklodowska Curie ETN, PBNv2: Next generation Pass-By Noise approaches for new powertrain vehicles (coordinator)• EU H2020 Marie Sklodowska Curie ETN, SmartAnswer: Smart mitigation of flow-induced acoustic radiation and transmission for reduced noise• EU H2020 Marie Sklodowska Curie ETN, Acoutect: A sound fundament for our future buildings• EU H2020 CSA, Science2Society: Improving university, industry and society interfaces to boost the throughput capacity of Europe’s innovation stakeholders (coordinator)• COST Action, CA15125, DENORMS: Designs for Noise Reducing Materials and Structures• EU H2020 Marie Sklodowska Curie EJD, VIPER: Vibroacoustics of Periodic media• EU H2020 Marie Sklodowska Curie ETN, ITEAM: Interdisciplinary Training Network in Multi-Actuated Ground Vehicles• EU H2020 Marie Sklodowska Curie ETN, SSeMID: Stability and Sensitivity Methods for Industrial Design• EU FP7 Marie Curie ITN, ANTARES: Advanced Training and Research in Energy Efficient Smart Structures (coordinator)• Flanders Make SBO project JOINTTOOL: Characterisation and modelling of joints• Flanders Make SBO project IMALIGHT: Integration and manufacturability aspects of lightweight structures exploiting inherent dynamic properties• Flanders Make SBO project MOFORM: Model based force measurements• Flanders Make SBO project EMODO: Efficient model based design parameter exploration and optimization in mechatronics• Flanders Make ICON project EVIT: Model-based experimental-virtual testing• Flanders Make ICON project OPTIMULTI: Optimal design of multi-material structures• Flanders Make ICON project MODA: Model based data analytics• Flanders Make ICON project MULTISENSOR: Multi-sensor system design and validation• Flanders Make ICON project CONCEVAL: Multi-attribute concept evaluation of lightweight structures• Flanders Make ICON project Drivetrain_Codesign: Physical and control co-design of electromechanical drivetrains for machines and vehicles• SIM SBO project M3/MOR4MDESIGN: Model order reduction for efficient multi-scale, multi-parameter, multi-attribute and multi-material design• SIM SBO project M3/DETECT-IV: Model-supported development of NDT methods for defect detection in composite parts• SIM SBO project MADUROS/DeMoPreCI-MDT: Development, monitoring and prediction of coupled interactions in material durability testing• SIM IBO project M3/FATAM: Fatigue of additive manufactured components• SIM ICON project M3/DETECTION: Model-supported non-destructive testing for the detection of defects in lightweight structures: an industrial solution• VLAIO O&O project no. 155015 , WERECLEAN: Weight Reduction Cleaning• VLAIO O&O project no. 150958, ENDURANCE: Efficient durability testing and vehicle usage evaluation• IWT O&O project no. 150394, ECO-Powertrain: Innovative NVH testing and simulation methods for eco-efficient powertrain engineering• IWT Baekeland project no. 140768, Model based condition and parameter estimation of the high-dynamic behaviour of mechatronic weaving looms• IWT Baekeland project, Methodology development for use of high-fidelity physical models in couple input/parameter/state estimation of mechatronic systems in aeronautics• FWO doctoral grant strategic basic research 1S24918N, Design and analysis of compact, lightweight material concepts for sound mitigation in flow ducts• FWO doctoral grant strategic basic research 1S39517N, Model Based System Engineering approaches for the identification and monitoring of mechatronic systems• FWO doctoral grant 1106016N, Development of model order reduction techniques for mechatronic system models in inverse problems• FWO doctoral grant 11ZH817N, Design of tuned lightweight metamaterials for broadband sound transmission and sound absorption• FWO postdoctoral grant 12D2614N, Efficient prediction techniques for the design and dynamic analysis of innovative lightweight materials with favourable vibro-acoustic properties• FWO postdoctoral grant 12D1617N, Development of adaptive model order reduction strategies for simulation and state-estimation of mechanical systems

A complete list of current and past research projects is available at www.mech.kuleuven.be/en/research/mod/Projects

Some key numbers of the research group:

Selection of on-going project funding:

• A 6 full time equivalent permanent staff,• 9 postdoctoral researchers,• and 74 PhD researchers, including 27 industrial PhDs.

Head of the group:Wim Desmetwim.desmet@kuleuven.be +32 16 32 25 27

Contact persons:Industrial research contact: Bert Pluymers bert.pluymers@kuleuven.be +32 16 32 25 29

Address:Celestijnenlaan 300 – box 2420 3001 HeverleeBelgium

Number of on-going PhD and postdoc Fellowships (incl. Marie Sklodowska Curie Fellowships)

Number of on-goingresearch projects

6 DOF multi-axial hydraulic shaker table (Team CUBETM)Dedicated LMS TWR software is used to allow accurate reproduction of requested load data or LMS MIMO random control is used to obtain desired power spectral density functions at certain points on the test structure. The shaker table allows normal payloads up to 500 kg, which can go up to 1000 kg for special applications. Test objects can be mounted on the five sides of the CUBE if desired, easing fixturing and replicating actual installation conditions. The displacement, speed and acceleration limits are, resp., a stroke of 101.6mm vertical and 50.8 mm horizontal; a velocity of 0.96 m/s; and an acceleration of 10g with a control bandwidth 0-300Hz.

Quarter car suspension test rigFor the validation of virtual sensing strategies, which aim to identify the loads acting on automotive suspension systems, two test setups have been developed. A first setup consists of a frame where a McPherson suspension system is attached, while the CUBE shaker table, a powerful 6-dof multi axial hydraulic shaker, can apply predefined loads on the wheel side. In a second test setup a twist beam suspension is fixed to a frame while the shaker applies the loads to the wheel.

Accelerated multi-axial fatigue experimentsA novel test setup is developed to subject cylindrical specimens of different sizes and materials to complex real-life loading con-ditions. Bending moments of 5–150 Nm can be combined with torsional moments of 5–200 Nm at test frequencies between 2 and 60 Hz. This significantly reduces the time and cost needed for the experimental validation of analytical and numerical fatigue calculations with respect to conventional fatigue testing techniques.

Flow-acoustic characterisation of duct systemsThis modular facility enables the acoustic characterisation of the transmission characteristics of duct elements of various dimen-sions such as HVAC and exhaust system components,… as well as the indirect determination of the acoustic impedance of sound absorbing wall treatments, both under quiescent conditions and in the presence of a mean flow. A mean flow up to a Mach number of 0.3 can be reached for duct diameters of 50mm with both uniform (Roots blower) and time-pulsating (cold engine simulator) flow fields. The experimental approach is based on an active multiport characterisation of the test objects using multiple flush-mounted pressure transducers and a combined multiple-source/multiple-load approach.

Open circuit aero-acoustic wind tunnelThe open circuit aero-acoustic wind tunnel is used for the aero-acoustic analysis of confined subsonic flow applications and low Mach number free-field applications. Flow visualisation measurements, carried out with stereo PIV (Particle Image Velocimetry), can be combined with acoustic in-duct and far-field pressure methods to characterise aerodynamic noise generation mechanisms and their far-field radiation. Anechoic, isothermal and low-turbulence inflow conditions are ensured by an acoustic labyrinth, a heat exchanger and a flow conditioner. Variable inlet conditions can be imposed using a frequency regulated Roots blower.

Lightweight components dynamic characterisation test rigThis non-standard test rig allows the experimental evaluation of the acoustic insertion loss of lightweight components for both air-borne and structure-borne excitations in a quick and very practical way. It consists of a concrete cavity of less than one cubic meter particularly shaped to ensure a desired distribution of the acoustic natural frequencies in the low frequency region. The front wall can be changed such that it can host test specimen of different sizes and thicknesses. The cavity can also be fully closed for acoustic absorption testing. Vibration levels, Sound Pressure Level, particle velocity and acoustic intensity can be measured over the radiating component in the frequency range [50-10000] Hz. The described system is a powerful tool to characterise and analyse novel materials and optimised lightweight components.

Impedance tubeAn impedance tube for acoustic impedance, reflection and absorption measurements has been developed. The measurement method is the two microphone transfer function method described in the standard ISO 10534-2. The error mechanisms which cause deviations on the reflection measurement have been investigated. A precision measurement head wherein the microphones are positioned has been developed, resulting in superior characteristics compared to the commercially available tubes in terms of accuracy and frequency range. The impedance tube has a diameter of 45mm. For a hard wall measurement, the reflection coefficient deviation with respect to the theoretical value remains within 1% for frequencies ranging from 30Hz until 2kHz.

July 2018

www.mech.kuleuven.be/mod

• Industrial Research Fund Mandate – Dynamics and Mechatronics: oxygen for innovating industry – Bert Pluymers

• LMS Chair on Vehicle Mechatronics – Wim Desmet

• Core lab DMMS (Dynamics of Mechanical and Mechatronic Systems) of Flanders Make (the strategic research centre for the manufacturing industry)

• Spin-offs: LMS International/Siemens Industry Software, DAP/Co-Services, SoundTalks

@KULnoisevib KU Leuven Noise & Vibration Movie Channel

kuleuven.mod

Virtual torque sensing on a mechatronic drivetrainThis test setup is purpose-built for exciting torsional driveline dynamics with minimal influence from the frame or its surroundings. Two 5,5 kW 2-pole induction machines can follow user-defined speed and torque profiles, including fast-transient and four-quadrant operation. One machine can be displaced laterally, such that the double-cardan transmission introduces non-linear torsional dynamics. The latter can also be replaced by other driveline elements. Electrical current and voltage measurements are available, as well as angular displacements, speeds and rotational accelerations. This allows model-based virtual torque sensing in a frequency range of 0–200 Hz. A built–in torque sensor allows quantitative experimental validation.

ElectroPulsTM E10000 Linear systemThe ElectroPulsTM E10000 Linear system is a state-of-the-art, all-electric test instrument designed for dynamic and static testing on a wide range of materials and components. It includes Instron advanced digital control electronics, Dynacell load cell, Console software, and the very latest in testing technology – hassle-free tuning based on specimen stiffness, electrically operated cross-head lifts, a T-slot table for flexible test setups. High dynamic performance, capable of performing up to 100 Hz, with ±10 kN dynamic linear load capacity. Linear stroke of 60mm. It is equipped with an environmental chamber (H 485mm, W 240mm) with advanced temperature control from -100°C to 350°C.

KU Leuven Noise & Vibration Research Group

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

111

20

10

3

FWO - Research Foundation FlandersFlanders Innovation &Entrepreneurship (VLAIO)European FrameworkProgrammes

KU Leuven

Bilateral industrial researchprojects

7 7

151

12

2

International funding agencies