STRUCTURAL OPTIMIZATION and its application in AUTOMOTIVE ... · ‒The shape of the structure can be modified to satisfy the defined design constraints and to minimize/maximize the

MSC Software

STRUCTURAL OPTIMIZATION

and its application in

AUTOMOTIVE INDUSTRY

VECOM training

“Simulation methodologies for vehicle structure”

9-10 February 2012, Firenze, Italy

Ing. Mauro Linari

Pro ject Manager

MSC Software S.r. l .

MSC Software

Design M odel

D e s ig n Va r i a b l e s

D e s ig n C o n s t r a i n t s

D e s ig n O b je c t i v e

Finite Element Analysis Program

Numerical Optimization

Program

BRUTE FORCE Method A ‘Brute Force’ coupling of an analysis program and an optimization program suffers from:

‒ Too many design variables

‒ Too many design constraints

‒ Too many detailed analysis

Finite Element Analysis Program

Numerical Optimization Program

Approximate Design Model

Improved Designs

Anal ys is M odel

T h e s t a n d a r d F EM a n d i t s s t r u c t u r a l

r e s p o n s e

• Approximate Design Model concept• It now acts as the interface between

the analysis and the optimizer• Properties of the Approximate Model

‒ Explicit approximations of the objective function and all retained constraints.

‒ It is updated by a full finite element analysis at every design cycle.

Structural OptimizationGeneral Consideration

VECOM 2012 – Firenze Feb 9, 2012

The structural responses which guide the design are implicit functions of the design variables. Function evaluation needs analysis execution at each design modification

Design Optimization is an automatic process of modifying a design to achieve a design objective

while satisfying constraint requirements

MSC Software

• SIZING

– Element and material properties can be considered as

design variables. Also some data in the connection cards

can be design variables

MSC Nastran - Structural OptimizationTypes of structural optimization & supported analysis

• TOPOGRAPHY

• The bead/stamp theory is used to improve the structural

behaviors of a component by varying its shape according

to predefined geometrical constraints

• SHAPE

‒ The shape of the structure can be modified to satisfy the

defined design constraints and to minimize/maximize the

objective function

• TOPOLOGY

‒ The optimal mass distribution in a predefined design

space according to applied loads and constraints.

Mass can be only deleted

• TOPOMETRY

‒ It is a special optimization procedure that uses sizing

design variables to define the optimal mass distribution.

Mass can be locally added or deleted


The structural responses of the

following analysis can be directly

used as constraints or objective

functions or to build new responses

by proper equations

‒ STATICS

‒ NORMAL MODES

‒ BUCKLING

‒ FREQUENCY RESPONSE

‒ RANDOM RESPONSE

‒ TRANSIENT RESPONSE

‒ STATIC AEROELASTICITY

‒ FLUTTER

‒ COMPLEX MODES

Dyn

amic

res

po

nse

s d

eriv

ing

fro

m in

tern

al o

r ex

tern

al a

cou

stic

an

alys

is c

an b

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ed

MSC Software

MSC Nastran - Structural OptimizationMSC Nastran flow optimization logics

It is repeated each n mathematical optimization design cycles

SIZING & TOPOMETRY

Yes

No

No

Yes

Repeated m types according to user request

SIZING

Mathematical optimization

Many timesNo

Yes

Mode Tracking

if „MODES

SIZING & SHAPE


MSC Software

• The basic concept of FSD can be described as follows:

• Fully Stressed Design (FSD) is an alternate approach to the Mathematical Programming (MP) approach for performing automated design tasks.

‒ It resizes the element properties so that each element is at its limit value

under at least one of the applied load conditions.

‒ It produces a „quick-look‟ design with a fraction of the computational cost

and can handle tens of thousand independent design variables.

• The FSD can be used either as a stand-alone tool or as a starting design for an MP run.

‒ User defines the number of FSD cycles (they are executed before the

standard optimization procedure by Mathematical Programming Approach)

• During FSD, the optimizer is not utilized although the standard design model input is used.

MSC Nastran - Sizing OptimizationFully Stressed Design

old

i

allowable

inew

i tt

t = des igned propertyi = index to indicat e which property conta ins the des ig n

parameter and the des ig n response = respons e quant i t y , such as st ress = a rea l number (0 .0 < 1.0)

( ‘old ’ and ‘ new ’ superscr i pt s refer to before and af ter res iz in g)


MSC Software

MSC Nastran - Sizing OptimizationFully Stressed Design


No Approximate Analysis

MSC Software

• The user specifies a list of „acceptable‟ values for design variables.

‒ Applicable to any design variable.

• The discrete solution is obtained by post-processing the

continuous optimal solution.

• Discrete optimization methods

‒ Design of Experiments (DOE)

• Picks the best discrete design from a set of candidates by evaluating the approximate

objective and constraints. The candidate set is determined using DOE methods.

‒ Conservative Discrete Design (CDD)

• Obtains a conservative solution based on the continuous optimal design by using sensitivity information

‒ Round up

• Simply rounds up to the nearest discrete value

‒ Round off

• Simply rounds off to the nearest discrete value

MSC Nastran - Sizing OptimizationDiscrete variable optimization


MSC Software

MSC Nastran - Sizing OptimizationDiscrete variable optimization


***************************************************************

S U M M A R Y O F D E S I G N C Y C L E H I S T O R Y

***************************************************************

(HARD CONVERGENCE ACHIEVED)

NUMBER OF FINITE ELEMENT ANALYSES COMPLETED 5

NUMBER OF OPTIMIZATIONS W.R.T. APPROXIMATE MODELS 3

NUMBER OF DISCRETE PROCESSING ANALYSES COMPLETED 1

OBJECTIVE AND MAXIMUM CONSTRAINT HISTORY

---------------------------------------------------------------------------------------------------------------

OBJECTIVE FROM OBJECTIVE FROM FRACTIONAL ERROR MAXIMUM VALUE

CYCLE APPROXIMATE EXACT OF OF

NUMBER OPTIMIZATION ANALYSIS APPROXIMATION CONSTRAINT

---------------------------------------------------------------------------------------------------------------

INITIAL 6.614414E+02 1.102773E-01

1 5.662242E+02 5.662401E+02 -2.791767E-05 9.536743E-06

2 5.474170E+02 5.474160E+02 1.783949E-06 2.966779E-03

3 5.474160E+02 5.474160E+02 0.000000E+00 2.966779E-03

3D 5.291842E+02 5.291818E+02 4.613550E-06 3.849362E-02

---------------------------------------------------------------------------------------------------------------

0

DESIGN VARIABLE HISTORY

----------------------------------------------------------------------------------------------------------------------------------

INTERNAL | EXTERNAL | |

DV. ID. | DV. ID. | LABEL | INITIAL : 1 : 2 : 3 : 3D : 4 :

----------------------------------------------------------------------------------------------------------------------------------

1 | 1 | X1 | 2.0000E+00 : 1.0000E-01 : 1.0000E-01 : 1.0000E-01 : 1.0000E-01 :

2 | 2 | X2 | 2.0000E+00 : 2.0166E+00 : 2.0266E+00 : 2.0266E+00 : 2.0000E+00 :

3 | 3 | X3 | 2.0000E+00 : 2.8267E+00 : 2.9868E+00 : 2.9868E+00 : 3.0000E+00 :

4 | 4 | X4 | 2.0000E+00 : 1.0000E-01 : 1.0000E-01 : 1.0000E-01 : 1.0000E-01 :

5 | 5 | X5 | 2.0000E+00 : 3.5169E-01 : 1.0000E-01 : 1.0000E-01 : 1.0000E-01 :

6 | 6 | X6 | 2.0000E+00 : 7.8165E-01 : 6.8127E-01 : 6.8127E-01 : 7.0000E-01 :

7 | 7 | X7 | 2.0000E+00 : 1.7342E+00 : 1.6301E+00 : 1.6301E+00 : 1.5000E+00 :

8 | 8 | X8 | 2.0000E+00 : 2.8171E+00 : 2.6749E+00 : 2.6749E+00 : 2.5000E+00 :

Discrete Optimization Cycle Based on previous Standard Optimization Cycle

MSC Software

• Useful when eigenvalues (e.g. first roof bending, first torsional,

etc.) are being designed

• Modes are “tracked” based on a cross-orthogonality check:

where i and i-1 are the eigenvectors relative to two consecutive optimization cycles

‒ If the mode order is not changed after the last optimization cycle the

diagonal term of the resulting matrix is non-null (with corresponding null

out of diagonal terms

‒ If the mode order is changed the off-diagonal term is non null, highlighting

which modes are involved

‒ In this condition the program updates automatically the response entry to

follow the mode to which we are interested

• The user must only define the modes to be tracked

Sizing OptimizationMode Tracking Features

iii

T

i tM 1


MSC Software

• Topology optimization determines the optimal shape of a part

• The design variables are the effectiveness of each element

Topology Optimization within the Design Process

FE ModelBasic Topology Result

Results With Manufacturing ConstraintsSmoothed and RemeshedFinal CAD Geometry

CAD Definition of Design Space

Topology OptimizationBrief Introduction

What Can I Use Topology

Optimization For?

• Static Load Path

‒ Multi-subcase

• Frequency Constraint

• Frequency Response

• Multidisciplinary

‒ Static + Modes + Freq

Response + sizing

• Benefits

‒ Used in early design to obtain component designs and shapes

‒ Used to redesign existing components

S p a r e t i r e m o u n t


MSC Software

Cyclic Symmetry constraint

• Motivation for Manufacturing Constraints

‒ Topology optimized designs may require major modifications for production or are not producible at all

Casting Extrusion

Without restriction

Design Space


Topology OptimizationManufacturability Constraints

• Common issues with unrestricted topology optimization

‒ Thin beams

‒ Cavities which are not achievable by casting or machining process

‒ Tapered sections

‒ Unsymmetric design even when loads, boundary conditions and design space are fully symmetric

‒ Etc.

MSC SoftwareVECOM 2012 – Firenze Feb 9, 2012

Optimization at AUDIOptimization and correlation NVH in the Full Vehicle Analysis

MSC Software

Topology optimization of the threshold profile (extruded Al.)


Optimization at AUDIOptimization and correlation NVH in the Full Vehicle Analysis

MSC Software

• Topology can be combined with other types of optimization classes

Design model

• Maximize the 15th natural frequency

• Red: topology design region with

extrusion + mirror symmetry constraints

• Green: sizing (thickness) variables

• Topology mass saving 50% & sizing

mass no change

15th natural frequency

Initial Design 27.316

Topology only 28.174

Combined Topology/Sizing 29.210

Topology only

Combined sizing/topology

Topology optimizationCombined Sizing/Topology optimization


MSC Software

• The main objective is to minimize the compliance of the front

mount beam of the engine

The areas highlighted in blue (relative to the constraints regions) should not be touched by the process of topology optimization

DESIGN SPACE

14 loading conditions

relative to different load

combinations acting in the

holes of the connection in

case of the most critical

maneuvers

XYZ Displ. constraints at 5

selected Grids:

- 6. < Δu > + 6.

Topology optimization – Aircraft Engine MountProblem definition


MSC Software

• It shows the structure obtained as result of topology optimization

Topology optimization – Aircraft Engine MountAnalysis of the results – Patran Post-Processing


Optimized Geometries ‘SMOOTHED’

Solution withoutmanufacturing constraints

Solution in case ofcasting constraints

DESIGN SPACE

MSC Software

• Element-by-element sizing optimization

• Topology/ Topometrycomparison

‒ Topology optimization is a “0” or

“1” discrete element-by-element

optimization methodology

‒ Topology optimization can be

used to decide which element

should be retained and which

element should be discarded

from the design space

‒ On the other hand, topometry

optimization aims to get a

continuous variation of the

designed properties

• Benefits

• It is good to identify critical design

regions

• It is good to locate where to add or

remove material to improve

structural performance.

• Topometry optimization is good for

finding the optimal location of spot

welds. In particular, topometry

optimization is very useful for some

properties that are not supported in

topology optimization; for example,

PDAMP, PELAS, PMASS,

PBUSH, PVISC, PGAP, PACBAR,

and PFAST

Topometry optimizationBrief introduction


MSC Software

BIW model correlation /application of topometry optimization


Optimization at AUDI Optimization and correlation NVH in the Full Vehicle Analysis

MSC Software

BIW model correlation /application of topology-topometry optimization



MSC Software

BIW model correlation /application of topology-topometry optimization



MSC Software

• The Finite Element model used in the optimization

at Volvo Cars is a fully trimmed sedan model

– The overall model size is about 12M structural DOFs

– The air in the passenger compartment is modelled with solid

elements and coupled to the structure using ACMODL

automatic coupling

• The part of the body set up as design variables is

a BIW except roof and side outer panels.

– The total number of elements in design space is 418148

(number of design variables)

• Eigenfrequencies are solved up to 750 Hz for both

fluid and structure using ACMS

• Case study 1

Optimization of Noise Transfer Functions (NTF)

• Case study 2

Optimization of Road noise level

20

Example trimmed body (TB) model – windows

removed for interior visibility

Example part of a BIW constituting optimisation

set of 418148 shell elements

Optimization at Volvo Car Corporation NVH CAETopometry optimization for noise reduction


MSC Software

Optimization set up:

• Minimize the sum of sound pressure in

Driver‟s and front passenger‟s ear position

• Excitation is applied in rear subframe front

mounts in vertical direction

– this is one of the known major transfer paths

for road noise

• Frequency interval is 20-250 Hz

• Constraint is set on the mass to keep it

unchanged

• The thickness in the design space is

allowed to increase a factor of 2 and

reduce to a factor of 0.5 of its original

thickness

• The lowest allowable thickness is 0.6 mm

• This jobs is run both in MSC Nastran 2008

using BIGDOT and in MSC Nastran 2011

using IPOPT and the results are

comparable

Optimization at Volvo Car Corporation NVH CAE

Case study 1 - Optimization of Noise Transfer Functions (NTF)

Results:

• The NTFs after optimization show a

significant reduction compared to the

original

• More that 10 dB reduction is seen at

high peaks, which is very impressive

• Although NTF curves are a bit different,

both BIGDOT and IPOPT show similar

reduction

Lo

we

r is

be

tte

r


MSC Software

Post-processing thickness

distribution after design cycle 6

• Red means thicker and blue means

thinner elements and is relative to the

original thickness of the panel

• Significant difference between BIGDOT

and IPOPT in thickness distribution

22

Thickness distribution with MSC Nastran 2008 + BIGDOT

Thickness distribution with MSC Nastran 2011 and IPOPT


Case study 1 - Optimization of Noise Transfer Functions (NTF)

• Studying this area more in detail

• Both optimizers find similar critical areas

• IPOPT seems to make a more continuous distribution

with less checkerboard effect

• The results from IPOPT are also more symmetric (at

least for this model) which makes more sense since

the loading and response is symmetric

• This is also appreciated by designers since the car

body is normally as symmetric as possible


Rear floor panel

MSC Software

Optimization set up:

• Minimize the sum of sound pressure in

Driver‟s and front passenger‟s ear position

• Excitation is applied in all chassis

attachment points in one load case

• The forces have magnitude and phase and

come from measurements and vehicle

simulations in proprietary software

• Frequency interval is 50 to150 Hz and 200

to 250 Hz

• Constraint is set on the mass to keep it

unchanged

• The thickness in the design space is

allowed to increase a factor of 2 and reduce

to a factor of 0.5 of its original value

• The lowest allowable thickness is 0.6 mm

• This jobs is run only in MSC Nastran 2011

using IPOPT23


Case study 2 - Optimization of Road noise level

Results:

• Significant reduction in the range 70-150 Hz

• Also large reduction at the tyre resonance

at 230 Hz

• The overall reduction in the front seats are

about 2 dBA

• Reduction is also noticed in the rear seat,

even though not included in optimization

• 2 dBA can be the difference between an

average car and a silent car

5 dB


MSC Software

Postprocessing element distribution


Case study 2 - Optimization of Road noise level


Red means thicker and blue means thinner elements

and is relative to the original thickness of the panel

• The suggestions are fairly clear and also

rather symmetric which helps in designing

realistic reinforcements

• Suggestions from the optimizer are to increase

gage for floor and C-pillar area

• Reduction in gage can be done in A-pillar,

B-pillar and front area

• Reductions, however, are always a compromise

with other attributes such as safety and

durability

MSC Software

• Also called Bead or Stamp Optimization

• Generate an innovative design proposal for reinforcement bead

pattern with a given allowable bead dimension (minimum bead

width, maximum bed height, and draw angle).

• Topography optimization is particularly powerful for sheet metal

parts

• It is treated as a special shape optimization and built on SOL 200

shape optimization technology

– New algorithms were developed to generate shape design variables and

shape basis vectors automatically based on the user's provided bead

dimension

• Many design variables are generated in the topography optimization

– The adjoint design sensitivity analysis method and large scale optimizer play

key roles in solving topography optimization problems

• All the analysis supported in SOL 200 can be used

Topography OptimizationGeneral Information


MSC Software

• The user can provide allowable bead

dimension

• Grids associated to loads and

boundary conditions are skipped

• Remove and/or add designable grids

• Support PSHELL, PCOMP (PCOMPG),

and PSHEAR

• Sizing, shape, topometry, topology

and topography can be combined in

a single job

Non-design elements

MW

MH

ANG

Non-design elements

Design elements

No buffer zone

Buffer zone

Topography OptimizationTopography Optimization Features


MSC Software

Maximize 1st Frequency‒ Des ign the base on ly

MW

MHANG

If needed the position of

some grid points in the

design region can be fixed

by:

– Defining the affected region

– Declaring it in the Topology

Optimization control entry

After Optimization

1th frequency: 654 Hz

Before optimization

1th frequency: 582 Hz

Min imum wid th (MW )= 10 .0

Max imum he igh t (MH)= 20 .0

Draw ang le (ANG) = 70 .0

Gr ids descr ib ing the ho les a re f ixed

Topography OptimizationModal Analysis Example


MSC Software

Conventional Design‒ Weight=11.39; F1 = 79.5Hz

- Case 1 -

Object ive: Max Freq

Constraint: none

F1=61.0 Hz

Wt = 10.91

13 cycles

Initial Design is ‘Flat’ PanelR=90., Θ=28.6°

Z=30., t=.08

Wtinit=10.78,

F1init=16.8Hz

- Case 2 -

Object ive: Min Wt

Constraint: F1>35Hz

F1 = 36.0 Hz

Wt = 10.81

6 cycles

Topography OptimizationReal life example


MSC Software

• Standard Practice (Manual Procedure)

– The model is manually partitioned into

designed and non-designed parts

– The non-designed part is treated as an

external superelement while the designed

part is treated as the residual

– Component Modes Synthesis is applied to

the external superelement and boundary

matrices are stored in the database

– A separate assembly run is performed that

assembles the boundary matrices into the

residual model for solving system solution

– Efficient in terms of CPU time, but tedious

in data manipulation

• AESO automates the tedious manual

partition process by identifying and

partitioning the whole model into the

designed part and non-designed parts,

and performing CMS reduction for non-

designed parts

• Designed part consists of:

• Grid/elements that are designed and constrained

• Grids/elements that are associated with applied loads

• Rigid elements and MPC equations that are touched

by designed grids

• Two separate Nastran runs

• An AESO creation run

• Automatic partition in designed and fixed parts

• Assembly file creation

• Boundary matrices generation

• An AESO assembly run

• The original design task is performed on the reduced

residual structure

Advantages of AESO Technique

Efficiency

- Design task solved in a reduced residual model

- Smaller Residual (10% or less) higher Speed Up

Easy-to-use

- Removes possible user errors

- Minimal knowledge and experiences in superelements

utomatic xternal uperelement ptimization AESO General Information


MSC Software

Dynamic Optimization of A car body

Analysis model statistics

‒ 207098 grid points

‒ 1.24 million DOFs

‒ 209079 elementsVehicle model

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9

Design Cycle

Clo

ck T

ime

(Min

ute

)

Total Time (Single Run)

Total Time (AESO)

utomatic xternal uperelement ptimization AESO sample - Performance

Design task statistics

‒ Design variables: vary the height and width

of some box cross sections of 183 beam

elements

‒ Objective: minimize the structural weight

‒ Constraints: maintaining 1st, 2nd and 3rd

modes above given limits

The final objective by AESO matches that of a single shot run within a relative error of 1%

Speed up is 4+ fold


MSC Software

Analysis Domain Design Domain

Update

Displacement Field

Multiple Loading Condition

The optimization process is subdivided in two domains:Analysis Domain and Design Domain

Non linear static analysis is performed in the analysis design

The displacement field is evaluated and the equivalent load sets are derived from it

The equivalent load sets are transmitted to the design domain

Linear static response optimization is performed by using the equivalent static loads as external loads

The design variables are updated in the design domain and non linear static analysis is performed again with the updated design variables


Nonlinear Response OptimizationEquivalent Static Loads Method (ESLNRO)

MSC Software

Nonlinear Response OptimizationEquivalent Static Loads Method (ESLNRO)

MSC Software

Topology Optimization with Contact

• What is supported

‒ Sizing, shape and topology optimization

task

‒ Nonlinear static analysis response

(ANALYSIS = NLSTAT)

‒ Geometric and Material Nonlinearities

‒ Response type like displacement (DISP),

STRESS, WEIGHT and VOLUME

‒ Also synthetic responses are supported

(DRESP2)

‒ Contact Conditions and further responses

like reactions (SPCFORCE), fraction of

mass (FRMASS) and compliance (COMP)

Nonlinear Response OptimizationGeneral Behaviors


MSC SoftwareVECOM 2012 – Firenze Feb 9, 2012

Nonlinear Response OptimizationImplementation

• The ESLNRO is implemented in MSC

NASTRAN Implicit Nonlinear Solution

(SOL400)

• The single user input file includes

‒ The nonlinear analysis model

‒ The design model with its design variables and

nonlinear response constraints and objective.

• A multiple Nastran invocation strategy

works behind the scenes to harness the

strengths of SOL400 (MSC Nastran

Nonlinear Implicit Solution) and SOL200

(MSC Nastran Optimization Solution)

together to provide an integrated

solution to the design task.

• The submitted job runs to one of the

termination criteria with no need for user

intervention or manual file transfer.

MSC Software

Nonlinear Response OptimizationCase Study – Joined-Wing Aircraft


“ The joined wing design is currently being

considered for application to high altitude long

endurance Unmanned Aerial Vehicles (UAVs).”

Consider starboard wing

The length from the wing-tip to the

wing-root is 38 meters and the length

of the chord is 2.5 meters

MSC Software

Nonlinear Response OptimizationCase Study – Joined-Wing Aircraft

Significant nonlinear behavior

– Large displacement

– Critical Physics: snap over buckling behavior at approx 50% load

Normalized Results

– Max Deflection

• Optimized: 1.0, Initial 5.96

– Max VonMises

• Optimized: 1.0, Initial 23.3

O p t i m i z e d S o l u t i o n

0

1000

2000

3000

4000

5000

6000

7000

8000

0 10 20 30

Design Cycle

Weig

ht

- B

lue

0.01

0.10

1.00

10.00

100.00

Max C

on

str

ain

t (

Red

)

(Lo

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cale

)


MSC Software

Opt imizat ion Process

Optimization using different design modelsMulti-Model Optimization Process

This enables support for the ability to perform design optimization when the design conditions are produced by two or more MD Nastran design models

The M u l t i O p t application initiatesservers that start the processing of theseparate design models up to the pointwhere the optimization is to occur

At this point, a new server is invoked to merge the design information, perform the optimization and partition the results

The servers running the individual models are then resumed in a design loop that is terminated when either convergence is achieved or the maximum design cycles are reached


MSC Software

Model 2 – Built for stress AnalysisGrids = 19411Elements = 19640Design Variable = 9

Model 1 – Built for Torsional Stiffness AnalysisGrids = 5613Elements = 5970Design Variables = 10

Model 3 – Built for Acoustic Analysis (FRF)Grids = 13761Structural Elements = 5970Fluid Elements = 7829Design Variables = 10

Each model is built according to the

request of the specific type of analysis

Optimization using different design modelsTest Case using three different input models

Results

The design overcame a violated

constraint while reducing the

weight from 643. to 573.


MSC Software

Structural OptimizationOpen Architecture - SCA Framework Overview

• The Simulation Component Architecture (SCA),

enables the delivery of MSC‟s core simulation

technology, as well as user developed

technologies, as reusable software components

• Nastran components wrapped in SCA, are MSC

Nastran functionalities packaged as reusable

services, known as components

MSC Nastran

SCA

…

MSC components

SCA

Inp

ut

File

Pro

cess

or

(IFP

)

SCA

Load

Man

ager

SCASo

luti

on

Man

ager

…

SCA

OU

TPU

T FI

LE P

roce

sso

r

(IFP

)

SCA

Use

r D

efin

ed S

ervi

ce(U

DS1

)

SCA

Use

r D

efin

ed S

ervi

ce(U

DS2

)

…

User components

• SCA framework

utilized CORBA as

the communication

protocol between

services

• „Open‟ Optimization

‒ External Response

‒ OpenMDO

MSC Software

• MSC Insight is an Adams tool originally built for performing parametric

analysis with Adams.

• MSC Insight structure allows to drive Design of Expriment (DoE) of most

popular MSC simulation engines

• In order to investigate :

‒ Parametric sensitivity and coupling (design understanding, test / analysis correlation)

‒ Optimisation strategies (model updating, design improvement)

‒ Robustness of operating points (manufacturing tolerances)

• Related investigations are based on the identification of polynomial

approximations

• After Design of Experiment phase, the same tool can drive a complete

optimisation of the fully non-linear simulation model (instead of using the

polynomial approximation) .

A different approach to OptimizationDoE : the process through MSC Insight

MSC Software

A different approach to OptimizationDoE : the process through MSC Insight

MSC Software

Seal cross section

Body

Door seal has 2 types

of solicitations

Objectives : behavior between

Min/max and mass reduction

A different approach to OptimizationOptimization demonstrator of Car door seal

MSC Software

External thickness =

nominal +/- 0.8 mm

Internal thickness =

nominal +/- 0.5 mm Height =

Nominal +/- 1 mm

A different approach to OptimizationAutomation process and Parametric modeling: Factors (Inputs)

MSC Software

This document is the property of MSC.Software : it can not be copied or given to a 3rd party without MSC.Software written agreement . Page 48

Total mass

Compression

loads

Min / Nom / Max

Horizontal

Radial

A different approach to OptimizationResponses (outputs)

MSC Software

A different approach to OptimizationInvestigations

This document is the property of MSC.Software : it can not be copied or given to a 3rd party without MSC.Software written agreement .

!

Clearance body/door

Compression loads

This values are under min curve

Statistics

Response Surface

Coupling &

robustness

Optimization

MSC SoftwareThis document is the property of MSC.Software : it can not be copied or given to a 3rd party without MSC.Software written agreement .

Result of optimisation

Optimized parameters on response surface

Surface de

réponse

Calcul de

vérification

Marc

Diff %

EP_INT_CENT 1,0 1,0 0,0%

EP_EXT_CENT -0,8 -0,8 0,0%

HAUTEUR_CENT -0,7 -0,7 0,0%

Mass_gram 27,6 27,6 0,0%

Mass_tube_gram 9,9 10,0 -0,6%

H_F_min 6,6 6,6 0,7%

H_F_nom 8,2 8,3 -0,2%

H_F_max 8,8 8,9 -1,0%

H_LSQR_norm 0,39 0,30 27,9%

H_LSQR 3,5 2,9 21,2%

R_F_min 4,6 4,6 1,1%

R_F_nom 6,9 6,7 3,7%

R_F_max 7,7 7,6 1,6%

R_LSQR_norm 0,39 0,33 18,6%

R_LSQR 3,4 3,5 -2,0%

Optimum

A different approach to OptimizationOptimization: starting from DOE

MSC Software

Structural OptimizationConclusions

You can …

Improve performance of existing projects

Combine designers experience to less intuitive

analytical solutions in the preliminary phase of the

project

Take advantage of nonlinear analysis results in design

optimization

Improve efficiency and easy-to-use

Access to in-house/third-party results or optimizers by

taking advantage of the MSC Nastran Open

Architecture

Use stochastic procedure to optimize or check the

robustness of a project

MSC Software

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STRUCTURAL OPTIMIZATION and its application in AUTOMOTIVE ... · ‒The shape of the structure can be modified to satisfy the defined design constraints and to minimize/maximize the