Baskar RajagopalanProduct Manager, MSC.Software

Realistic Simulation of aRealistic Simulation of aFlexible Mechanism using MSC.SoftwareFlexible Mechanism using MSC.Software’’s s

SimEnterprise SolutionsSimEnterprise Solutions

MSC SimEnterprise Solution SetMSC SimEnterprise Solution Set

Model development• SimXpert Structures, Motion Workspaces• Expert/method analyst focus• Advanced MD environment• Best practice author/capture for re-use• Simulation process automation

MD Nastran / SimXpert Motion Solver Technology• Common, Multi Discipline embedded solver foundation• Cross platform all-in-one simulation engine• Enterprise computing access via gateway

MD Workspaces

High Level Solution ProcessHigh Level Solution Process

MD Nastran / SimXpert Motion• Drop test Simulation• Flexible Body Motion• Structures Optimization

CATIAData Simulation

Model

Results

Landing Gear Simulation ProcessLanding Gear Simulation Process

• Process Details– Attach to initial geometry in CAD models

– Develop a multi-body dynamics (MBD) model of the LG assembly• Include flex bodies where appropriate• Inner & outer cylinder only

– Use MBD model to simulate rigid and flexible landing conditions

– Extract time domain loading conditions from the flexible landing simulation

– Develop an FE model of the LG assembly• Re-use flex parts & joints from MBD model

– Use FE model to simulate quasi-static applied loads

– Apply the quasi-static applied loads and simulation loads to topological optimization of the LG assembly components

– Update geometry of the LG components based on simulation(s)

Landing Simulation ResultsLanding Simulation Results

AVI

Landing Simulation ResultsLanding Simulation Results

Load-Stroke Response

Vertical tire reaction

Damping coefficientDamping coefficient

Damping Coefficient Vs Stroke

• Initial damping curve resulted in loads outside design envelope• SimEnterprise supports simulation of active damping and shock strut metering pin

design– For this study the revised curve was obtained through simple iterative studies

S

CD

Landing & Taxiing Simulation ProcessLanding & Taxiing Simulation Process

• Process Details– Utilize CATIA geometry– Model lugs so they can be easily

modified without affecting the cylinder meshes

– Mesh solids– Define properties– Define contacts at joints and

“glue” lugs back on– Conduct static analysis based on

loads from dynamic landing simulation and known braking/turning loads

– Review results

Braking, Turning and Landing Braking, Turning and Landing -- Simulation ResultsSimulation Results

Braking Turning Landing loads

Design OptimizationDesign Optimization

• Process Details– Define ‘design’ region – for this

demonstration the upper and lower links were considered ‘designable’

– Conduct topology optimization (MD Solver technology) to determine distribution of material in links

– Review results and output geometry from topology optimization back to CAD system

– Define new geometry in CAD system that allows the definition of design variables for shape optimization

– Conduct shape optimization for design variables

Link OptimizationLink Optimization

Topology design regions Optimized topology

Optimized topology to CADOptimized topology to CAD

Optimized topology

Smoothed….

Imported to CAD

Refined CATIA Geometry

Lug Design EvolutionLug Design Evolution• Engineering judgment leads to addition of fillet radii• Shape optimization quantifies optimal radii dimension

Summary / Closing CommentsSummary / Closing Comments

• Flexible landing gear simulation process successfully completed

• Leveraged key strengths of SimEnterprise solution set

– Single simulation environment– Model re-use across disciplines –

common data model– Integrated MD solver– Native access to CAD geometry – no

translation• Additional capabilities not

demonstrated– Control system integration - active

damping– Fluid/gas simulation of shock strut with

metering pin – Feature optimization based on mesh

morphing– Integration of flight dynamics