Sag Analysis of an Automotive Roller Blind System in Terms of the Variation in the Production...

Sag Analysis of an Automotive Roller

Blind System in Terms of the

Variation in the Production Process

5th European HyperWorks Technology Conference (EHTC) November 7 – 9, 2011

Bonn, Germany

D. Bernhardt, R. Peter

Inteva Products

Roof Systems Germany GmbH, Dietzenbach

European HyperWorks Technology Conference , November 7 – 9, 2011

Agenda

Introduction

Determination of Input Parameters

Determination of Transfer Functions

Determination of Input Parameter Variations

Monte-Carlo Analysis Results

Summary & Outlook


Inteva Products

42 Locations – 18 countries – 4 continents

2.2 Billion USD Annual Revenue

2008 Inteva was born from Delphi Closures & Interiors

2011 Inteva Acquires ArvinMeritor’s Body Systems Business Unit

Closures: Motors & Electronics:

Interior Systems: Roof Systems:

http://insideinteva.intevaproducts.com/sites/Marketing/Product Photography/Low Resolution/White Background/Cockpits/CKPITWBLR.jpg


Roller Blind System

Main customer interface requirements

Proper optical impression No significant sag of the fabric

Reliable operation to control light exposure No strength, noise or operational issues mainly driven by lateral and transversal forces in the fabric

Due to the variations in the manufacturing process a predictive model for the sag and the forces in the roller blind system is developed to assess and optimize scrap rates in terms of

Material property limits

Process specifications


Main Steps for Statistical Prediction by Monte-

Carlo Approach

Determination of the

transfer functions

Key

characteristics

Random data

(Populations)

Determination of

main input factors Monte-Carlo

Analysis Determination of the

variation

of the input factors

OUTPUT INPUT ANALYSIS


Roller Blind System Design

Frame

Fabric

Cross Bow

Steel tape

Rollo Guide Rail


Determination of Main Input Factors

Quantitative determination of the effect of main components

Sequential disassembly of components and evaluation of differences, averaged for several samples

Following components are analyzed

Fabric

Cross Bow

Steel Tape

Force Measurement

-30

-20

-10

0

10

20

30

0 100 200 300 400 500 600 700 800 900 1000

Displacement [mm]

Fo

rce [

N]

Bow open

Bow close

Fabric close

Steel tape close

Fabric open

Steel tape open

Linear (Fabric open)

Linear (Steel tape open)

Linear (Fabric close)

Linear (Steel tape close)

extended

retracted


Parameter Diagram

Fabric

stiffness

Bearing

distanc

e

Normal

force in

fabric

Friction

coefficient

Fabric

operational

force

Rollo

operational

force

Sag

Steel

tape

force

Cross

bow

force

Pre-

tension

distanc

e

Production

process

Sun roof

assembly

process

Fabric

Weight


FEA Model for Sag Analysis

Fabric

Orthotropic material law

EZ, EX, EY

Half model application of symmetry conditions

and pre-tension distance in the fabric

Frame with mounting

conditions

Cross bow

Gap definitions to fabric

Steel tape merged to fabric,

coupled to frame

Analysis with ANSYS with large deformations

Application of

gravity load (1g)


Relationship Between Sag, Normal Force and Pre-

tension Distance

2

23

0*24

*

*

*

H

gs

AE

Hss

H

gsf

8

**

2

Sag

Clamping

displacement

[mm]

Froce

[N inY]

Relation

Force [%]

Sag

[mm in Z]

Relation Sag

[%]

FEA 46,58 100% 2,18 100%

Analytical 48,26 104% 2,279 105%1

Evaluation and Correlation of numerical & analytical results

Mag

Equations based on rope theory: FEA


Correlation Testing for Sag/ Normal Force

A fairly good correlation between analytical solution and measurement can be

achieved

0

2

4

6

8

10

12

14

0 2 4 6 8 10 12 14

Measured sag [mm]

An

aly

tic

al s

ag

[m

m]


Relationship Operational / Normal Force

Steel weights

Force measurement device

Rollo guide rails

Steel cable connected to steel tape

0

5

10

15

20

25

0 5 10 15 20 25

Normal Force

Fri

cti

on

Fo

rce

Test_1

Test_2

Linear

Determination of friction coefficient

Test is performed for several weights (normal forces)


Variation of Fabric Stiffness

0,0

50,0

100,0

150,0

200,0

250,0

0 0,2 0,4 0,6 0,8 1

Stress [MPa]

Secan

t E

-Mo

du

l [M

Pa]

1A 1B

1C 1D

1E 1F

2A 2B

2C 2D

2E 2F

3A 3B

3C 3D

3E 3F

4A 4B

4C 4D

4E 4F

5A 5B

5C 5D

5E 5F

50% 15,9%

0,135% 84,1%

99,87% Spec averg

Spec Min

Stress Strain data converted to secant E-Modulus

Consideration of non-linear behavior by defining E-Modulus depending on the stress

Variation can be captured by log normal distribution


Guide Rail

Guide Rail

Fro

nt P

art

Rear P

art

Panel 2

Rollo guide rail distance for

steel tape bearing Load case front part

1 mm

Load case rear part

Load case panel 2

1 mm

1 mm

Variation of Bearing Distance

The frame is over constrained

For the statistical analysis a sensitivity needs to be

calculated done by FEA models and unit load cases

Resulting tolerance can be calculated by including the

sensitivity in the RSS approach

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

0 200 400 600 800 1000 1200 1400

X-Coordiante [mm]

Y-D

isp

l. a

t b

eari

ng

[m

m]

Front Part_1 mm wider

Rear Part 1 mm wider

Panel_2 1 mm wider


Monte-Carlo Analysis Results

Scrap

Monte-Carlo Analysis in Excel (5000 samples)

Input of random data (populations, Minitab) derived from test results

Implemented analytical relations

Iteration of normal force

Calculation of sag

Prediction of out of spec parts

Scrap

Sag Operational Force


Summary & Outlook

The response of a fairly complex system can be calculated by relatively

simple analytical equations and approaches. This allows to cover the

variation in the analysis w/o exorbitantly increase the calculation effort

Key for this approach is to reduce the complexity of the analysis

approaches, but still capture the main effects correctly. Perquisite for this

is the availability of suitable test methods and data

Outlook

Further refinement of input statistics

Including additional input parameters to better represent noise effects

Sag Analysis of an Automotive Roller Blind System in Terms of the Variation in the Production...

Business

Transcript of Sag Analysis of an Automotive Roller Blind System in Terms of the Variation in the Production...