SNRD at FIAT to predict the risks for S&R in interior assemblies

SNRD at FIAT to predict the risks

for S&R in interior assemblies

Ismail Benhayoun, Altair PD Sweden

June 26th , 2014

Co-Authors: Mr. Tiago Ferreira , CAE Engineer, Fiat Automóveis, NVH

Mr. Paulo Eduardo Dal Bon Tonett, CAE Engineer , Altair Brazil

Mr. Charilaos Zografos, ESG Team Leader, Altair Sweden

Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.

Background

• Situation :

• FIAT encounter S&R issues

• CAE Driven Development at Focus

• Issues :

• S&R is only investigated with testing.

• No simulation method available at FIAT

• Question :

• How can FIAT transpose their S&R knowledge to simulation

using Altair’s experience and tools?


Presentation roadmap

FIAT & Altair

Next Steps

• Simplistic explanation

• Phenomena occurrence

& consequences

• Analyzing the

phenomena

E-Line & SNRD

D.I.R.T.F.T.

Squeak & Rattle in the

Product Development

Process

NOT a live demo of SNRD


Observing S&R occurrence and its consequences

Noise due to Rattle occurrence

Ref. SAE 2012-01-1553

Abrasion of paint due to Squeak occurrence

BMW 5 series workshop manuals (http://workshop-manuals.com)


Analyzing S&R phenomena

• Rule of thumb or established standards

• Physical testing

Ziegler’s Stick-Slip Test Stand SSP-04

3D Laser Vibrometry equipment (http://asdec.co/)


Product Development Process

Testing

Development Process

Virtual Engineering Validation

Simulation

Modal Analysis / F.R.A.• First Eigen Frequency

• Maximum Displacement

• Etc..

S&R Testing• “Quick fix”

• High Costs

• Too late!


Product Development Process

Testing

Development Process

Virtual Engineering Validation

Simulation

Modal Analysis / F.R.A.

S&R Testing

S&R Simulation – Risk Analysis S&R Simulation

• Early Identification of risk areas

• Drive the Design & Tolerances

• Decide on the most robust options

• Correlate and Improve

• Support the Validation

Process


Proposed Process to FIAT NVH Team

1. What do we need to perform such analysis?

2. How much effort is it to obtain the necessary inputs?”


NVH MODEL

Model definition & E-Line Method

• Linear Model

• No contact definitions

• Independent of penetrations and

intersections


Semi-Automatic process

Analysis process

Process ManagerSemi Automatic

Automatic post-processing

S&R FE-Lines

OptiStructModal Transient Analysis

Squeak and Rattle – Director


FIAT UNO – Trimmed Body In White


S&R Testing & Simulation

Test Simulation

Relative Displacement

Different road

conditions


Instrument Panel at Focus

Critical areas

Material Combinations

Packaging space

Static Tolerances

Line ID Line type Materials pair min-maxInterface

name

Gap dimension

[mm]Tolerance [mm]

1009 Rattle ABS85.180/PP_55.100 0.1-0.2 A1 1.0 0.3

4010 Rattle ABS85.180/PP_55.100 0.1-0.2 A2 1.5 0.3

7129 Rattle ABS85.180/PP_55.100 0.1-0.2 A3 2.0 1.2

10039 Rattle ABS85.180/PP_55.100 0.1-0.2 A4 1.0 0.8

13075 Rattle PP_55.100/PP_55.100 0.7-0.9 A5 1.2 0.5

16029 Rattle PP_55.100/PP_55.100 0.7-0.9 B1 0.8 0.5


Excitation loads

MBS

Different road conditions

Shaker from test lab

Generic PSD

Time domain

loads



FIAT & Altair

Next Steps

• SNRD outputs

• Sensitivity studies

• Chose of most robust

design

E-Line & SNRD

D.I.R.T.F.T.S&R simulation

based on relative

displacement due to

pseudo-random loads

in time domain


Automatic Rattle Evaluation in SNRD

Magnitude & Dynamic Tolerance


Automatic Squeak Evaluation in SNRD

Material Pairs : ABS85.180/PP_55.100

Impulse Rate Stick Slip Testing

(Ziegler)


Automatic Rattle Evaluation in SNRD– Detailed level

1.9 mm

2.5 mm

GAP

GAP -Tolerance


HyperMesh → OptiStruct → HyperView

SNRD PROCESS

AS A STAND ALONE PROCESS…


SNRD PROCESS

HyperStudy

Setup Parameter Study

HyperMesh

Model Setup

SNRDRelative Displacement, Dynamic Tolerance , Modal Contribution(frequency),etc…

Recognize all your

variables automatically

Model with the E-Line is

prepared

Define all variants to be run

and automatic call the post-

processing in SNRD

… THAT INTEGRATES IN A LARGE SCALE PROCESS


S&R an Iterative process – Sensitivity Analysis

IP to Floor Console interface – Effect of Modal Damping

2% 4% 6% 8%

25%

Predict and Anticipate the variations of real parts by estimating the consequences in term of S&R issues


Practical benefits - Update of Gap/Tolerances?

New


SNRD made for it

SNRDCAD Model

SNRD defines the gap and tolerance data as

metadata. Therefore:

+ No need for remodeling

+ No need to rebuild interfaces

+ No need to redo analysis

1 h

+ 0.5 h

+ 3 h

= 4.5 h

In SNRD

5 min

Vs.



FIAT & Altair

Next Steps

• Improve the capabilities

• Extend the applications

• S&R a driving load case

E-Line & SNRD


based on relative

displacement due to

loads in time domain


FIAT chose SNRD by Altair

• Methodology based on evaluation of relative displacement

• Rattle

• Provides a calculation of relative displacement along a gap

• Compares to the Gap size and Static Tolerance

• Provides a calculation of a Dynamic Tolerance

• Relative displacement can be directly correlated to Measured Displacement in test

• Squeak

• Calculation of relative displacement in contact plane

• New parameter that correlates to Stick-Slip measurement

SNRD offers you the possibility to choose between different technical

solutions at an early stage of the development process


FIAT & Altair PD Next Steps

Excitation loads• Loads measured at Xbeam, A-Pillar, Floor

• Loads in 3 Directions (X,Y,Z)

Material Data• Modal correlation at

the part level:

Compare some parts :

E-Modulus from

supplier vs.

manufactured part

Correlation• Test vs. Simulation

using SNRD

• Improve simulation

parameters to

develop a best

practice policy (i.e.

modal damping)

Dimensioning• Include Gap size and

Tolerances in SNRD

calculation

Stick-Slip• Create a database for

the most common

materials.


Door

Trim

FIAT & Altair PD Next Steps

Road To Lab To Math (R.L.M.)

Create A Best Practice Procedure To Evaluate & Reduce Risks For

Squeak And Rattle Issues In Interior Assemblies

Test on different tracks Test & Simulation

F(t) F(t)

IP

Accelerometers

{X,Y,Z}

Test Data

a(t)


From System Level to Full Assembly Validation

Interior CAE Team

Instrument Panel

Door Trim

Interior Trim

Exterior CAE Team Face/Exterior

Closures

Evaluation System Level Evaluation Assembly Level

NVH CAE Team

Trimmed BIW



System to full

assembly level

Improving the

capabilitiesE-Line & SNRD


based on relative

displacement due to

loads in time domain


More success stories about our

customers and the usage of SNRD on:

http://www.altairproductdesign.se/

Thank you!

For more information, please contact:

Ismail Benhayoun : [email protected]

Charilaos Zografos : [email protected]

http://www.altairproductdesign.se/

mailto:[email protected]

mailto:[email protected]