optimization centers a systematic deployment of structural optimization in large enterprises

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SAWE Paper No. 3563Track No. LCM

Category No. 16

Optimization Centers - a systematic deployment of structural optimization in large enterprises

Dr.-Ing. Lars Fredriksson, Director Altair ProductDesign

Altair Engineering GmbH

For Presentation at the

71th Annual Conference

of

Society of Allied Weight Engineers, Inc.

Bad Gögging and Manching – Bavaria, Germany –

05-10, May, 2012

Permission to publish this paper in full or in part, with credit to the author and the Society, may be obtained by

request to:

Society of Allied Weight Engineers, Inc.

P.O. Box 60024, Terminal Annex

Los Angeles, CA 90060

The Society is not responsible for statements or opinions in papers or discussions at the meeting.

This paper meets all regulations for public information disclosure under ITAR and EAR.



Page i

Table of Contents

Page

1. Introduction ....................................................................................................................................................1 2. CAE Structural Optimization – delivering optimized Design Concepts and Designs ...................................1 3. The Optimization Center - going from Tactical to Strategic Execution of Optimization ..............................3 4. Different Integration Levels ...........................................................................................................................4 5. CAE Weight Management Support ................................................................................................................5 6. Early Integration .............................................................................................................................................5 7. The real Value of an Optimization Center .....................................................................................................6 8. Implementation Examples ..............................................................................................................................7 9. Summary and Outlook ....................................................................................................................................9

ABSTRACT

In current product development processes, mass targets often have to stand back for functional targets in conceptand early product development stages. The focus on satisfaction of mass targets thus takes place later and it has

been proven difficult to fulfill the mass targets at this late stage without compromising the functional

requirements. Late “firefighting” activities, which are frequent in both the automotive and aerospace industries,

confirm this development dilemma.

In both aerospace and the automotive industry, dedicated weight managers have responsibilities related to weight

targets and their fulfillment. As of today, weight managers act predominantly based on experience, bench

marking and information regarding future usage of advanced materials in the products. CAE is today not as

widespread a tool to support the recommendations issued by weight managers.

An optimization center is a centralized structure within an OEM which allow for strategic execution of

optimization within the product concept and development processes. Differences between the current widespreadusage of optimization within OEMs and an optimization center are; 1) the direct (strategic) connection to

program management of product development, 2) the usage of optimization early to help propose baseline load

carrying structures which show potential to fulfill both functional and weight targets, 3) the consideration of

multiple (the important) functional requirements during concept optimization and 4) the application on larger

product subsystems in order to provide possibility to rearrange the load carrying topology between parts and/or

systems. An optimization center can additionally support weight managers with information gained from CAE

studies. This information would enhance the basis for decisions and could thus help to make better judgments of

realistic weight goals and about the distribution of weight on systems, subsystems and parts.

The optimization center is a competence center of excellence, where optimization knowledge relevant to the

products is concentrated, preserved and enhanced. The optimization center will assure 1) the creation and

compliance to standards for performing simulations and optimization within the OEM, 2) the continues build-upof knowledge and improvement of methods and processes, 3) the training of new center members to assure

continuation and redundancy of knowledge and 4) a flexible integration with standard development processes of

the OEM.

This paper and presentation will discuss how optimization centers work and can be created to fit requirements of

different OEMs. Advantages of optimization centers are presented and examples are shown how optimization

centers are used today to improve product development in the Aero and Auto industries.



Page - 1

1. Introduction

General standard product development processes of larger OEMs are predominantly focused to provide

satisfaction of functional requirements. Furthermore, the development process towards fulfillment of functional

requirements is often distributed, i.e. different teams or departments handle different attributes. This is common

practice in the CAE part of product development, where durability, stiffness and strength as well as NVH

attributes are commonly handled by different parts of the organization.

As a consequence of this approach, it has proven to be challenging to find the optimal tradeoff for the satisfaction

of the functional attributes. Tradeoff solutions acceptable for all attributes may consequently lead to mass

increases during the development. At later stages of the development process, demanding mass reduction targets

might be enforced by program management or weight management, leading to a reduction of structural

performance and a non-fulfillment of structural targets. At this stage of the development process, due to the

maturity of the design and the high costs associated with design changes, the tradeoffs available are not as

beneficial as tradeoffs made during the early part of development or during concept phase. Figure 1 shows a

principal development situation at two different times during the development process. At an early time in

development (Figure 1, left), a solution with reduced mass might be found without performance degradation.Later during development, (Figure 1, right) the same mass reduction might lead to performance degradation.

Figure 1: The available design space decreases during development caused by decreased development freedom

due to development constraints (costs, time, manufacturing, packaging, etc) during late development stages.

The current focus on environment (CO2) and the intense competition force companies to improve their

development processes for saving weight in the future. The automotive industry has set challenging goals for the

next 8 – 10 years [1]. For the aerospace industry, weight focus has a longer tradition. However, improvements in

the development process are still possible also in aerospace development.

2. CAE Structural Optimization – delivering optimized Design Concepts and Designs

Computer aided engineering (CAE) methods, such as structural optimization, are currently being generallyapplied in both aerospace and automotive industries to find and exploit weight saving potential. The industrial

usage of numerical optimization started off by applying optimization technology on existing designs and by

finding improvements to such designs with the goal to make them lighter, better performing or both. A further

development step of optimization has been the utilization on larger groups of parts, modules and subsystems. By

working on larger structures, load carrying functions can be redistributed from parts to other parts of the system,

thus utilizing the mass in a more optimal way. An important milestone in the usage of numerical optimization is

the multi-attribute optimization, where different global functional requirements (e.g. NVH, durability, crash, etc)

are considered simultaneously. Today, linearization techniques are available that allow experienced optimization

experts to consider nonlinear load cases in order to find new design concepts using gradient optimization

techniques such as topology optimization.

Realistic Design Limit

Current Design

Point

Weight P e r f o r m a n c e

New Weight Target

New Weight Target

Current Design

Point

P e r f o r m a n c e

Weight

RealisticDesign Limit



Page - 2

Today, numerical optimization methods are successfully used not only to improve existing parts and designs but

to find completely new design concepts during early development stages for large systems with different

functional requirements. These designs can be fundamentally different compared to designs proposed using

traditional methods. This phenomenon can be looked upon as an increase of the available design space with given

limits of time and costs. This is also explained and depicted in Figure 2. Thus, numerical optimization is to tool

to enhance the space of possible designs or a tool to exploit the available solution space better. These two

statements are different ways to look at the same phenomenon.

Figure 2: Using numerical optimization, solutions can be found (within acceptable costs and time limits) that are

not found without using this technique.

Comparable costs

Comparable costs

optimization improved designtraditional design

3 Months development3 Weeks optimization

(17% lighter, same stiffness)

optimizationdriven design

Design Space(CAD)

Requirements

Topology Optimization

(FEM)

Concept Design

(CAD)

Size/Shape Optimization

(FEM)

Final Optimized

Design (CAD)

Design Space

(CAD)Requirements


(FEM)

Concept Design

(CAD)

Size/Shape Optimization

(FEM)

Final Optimized

Design (CAD)

Figure 3: Optimization Driven Design compared to Traditional Design

New Weight Target

PhysicalDesign Limit

Realistic Design Limit

Current Design

Point

Weight

P e r f o r m a n c e



Page - 3

3. The Optimization Center - going from Tactical to Strategic Execution of Optimization

The concept of an Optimization Center (OC) has been developed to simplify the access to, and to enhance the

benefit of CAE optimization. Initially introduced to reduce the mass of individual components by changing their

form, OCs has developed into a generalized execution model for functional concepts and material decisions on an

assembly level. The concept of OCs provides close cooperation of optimization experts (including topology,

topography, form and parameter optimization), who are made available to work on-site at the OEM site and offer

individual services on an exclusive basis. These optimization experts work closely with existing representatives

for both design, packaging, functional attributes and weight. Every OC is scalable as it is possible to add

additional resources to every team as needed. Depending on the integration level (see below) and scale, different

number of “connector points” with the existing development organization will be created. The main differences

between the classical usage of optimization and an OC are depicted in Figures 4 and 5.

Figure 4: Classical tactical usage of CAE optimization by individual performance attributes teams

Figure 5: Optimization strategically hooked up to program management and weight management

Performance Attributes

Design Departments

CAE OPTIMIZATION

Tactical

P r o g r a m m e M a n a g e m e n t

Performance Attributes

M A N A G E M .

M A N A G E M . Optimization

Center

CAE CONCEPT DESIGN

Design Departments

CAE OPTIMIZATION / METHODS

Strategic

Weight Management

SCREENING & FEASIBILITY

CAE WeightSupport

P r o g r a m m e M a n a g

e m e n t



Page - 4

The Optimization Center addresses the fundamental questions of applying optimization, i.e.:

1) How should optimization be applied?

Optimization should be applied in a strategic manner, integrated with the standard development process.

2) When should optimization be applied?

Starting as early as possible in the design process where design freedom is still available to find solutions

which lead to minimal compromise in the tradeoff between functional requirements and weight.

Optimization should accompany the design process all the way until product release

3) Who should perform the optimization?

A dedicated team of experts hooked up to program management or similar functions within the OEM.

A dedicated team can build up, conserve and enhance knowledge and release this in form for processes

and methods in an optimal way.

The Optimization Center is the logical answer to these basic questions. The connection to program management

helps to integrate optimization technologies as part of the standard product development process, thus to applyoptimization driven product design.

4. Different Integration Levels

Although the optimization center will deploy all its advantages optimal when used on the product level and

connected to development program management, smaller scale centers can be introduced on a subsystem or

systems level, as depicted in Figure 6.

The first level of an Optimization Center is the direct cooperation with individuals or small groups responsible

for components and smaller subsystems. Usually, since the components' material and production processes are

already pre-defined, the experts can directly search for unused and removable material. An overall assessment of

cost effectiveness of components to control resources by importance is not done at this level.

The next level of method integration is based on cooperation with the OEM’s project managers of larger systems

or of the full vehicle. Those teams have the power to change functionality within the system or vehicle, which

offers a higher potential for optimization since it is not necessary that each component becomes lighter to reach

the system’s optimum. It is possible that single components – due to a change of function – might even be

heavier, but with an overall optimization of the system, this can be more than compensated for in other areas. At

this level of method integration, it is to do an overall assessment of cost effectiveness. Since the entire system is

analyzed, the engineers can apply advanced selection processes to prioritize certain topics.

SystemVerantwortung

1 2

3

System

Responsibility

ProductResponsibility

Funktions-gruppen

PartResponsibility

Larger strategic importance

OptimizationCenter

„WeightManagement“

Integration into

Program

Figure 6: Integration Levels of an Optimization Center



Page - 5

5. CAE Weight Management Support

The direct support of the weight management department of an OEM is in this paper denoted “CAE Weight

Management Support“. With the implementation of “CAE Weight Management Support” into existing weight

management functions, the existing weight teams and individuals will gain direct access to available knowledge

of the CAE studies performed in the OC (concept optimization, feasibility studies, robustness analysis and

stochastic assessments) and can also request these types of studies to be made, to gain as much information on

weight and performance as possible. In this way, the weight managers can draw better and more reliable

conclusions regarding the development progress and direction, and can be more precise on the input requirements

needed to reach the weight targets. Information that an OC can deliver to the weight management includes:

• an early understanding of the optimized basic structure and the associated mass,

• an early understanding of the impact on weight when using carry-over parts or systems, and

• an early understanding of the impact on weight of different concepts and design directions.

Figure 7 shows an idealized organizational structure for integrating an optimization center of the highest level

into an existing product development process.

Programme

Centre Manager (Weight Team)

Engineer 1 (Functional Attribute Team 1)



Senior Optimisation Exp ert

Optimisation Expert(s)

Weight Manager

Attribute Department Leaders

CAE Process Manager

Customer (Programme)

Owner – VP Product Development

In-House

Optimisation Centre

Steering Committee

Optimisation Lead

Consultants

Sof tware Developers

Process Experts

Expert Consultants

Figure 7: Idealized Structure of Top-Level Optimization Center

6. Early Integration

The earlier and more broadly an OC is integrated into a development process, the more efficient the results will

be, as described in the introduction. This rather simple formula describes the principal of the success of an OC.

Early in the development process of an aerospace or a vehicle structure, the engineers are usually still highly

flexible in their design. This should be leveraged, because at this stage it is decided if cost and timing, in relation

to the defined functionality and weight goals, can be kept until later in the development process.



Page - 6

Figure 8: Early Deployment of Optimization will help utilize existing Design Freedom

In this phase, weight management still has every possible design freedom and can make use of it by applying the

OC and the CAE Weight Management Support strategy to reach optimum results. If the engineers can make

reliable predictions on the system‘s weight and direct weight savings early, they will be able to save up to the

same amount in secondary weight [2] (automotive structures). The further the development process proceeds, the

less it can be positively influenced. The probability that compromises in function and weight have to be made, or

that the cost or time frame has to be adjusted, is higher at a later stage in the development process.

7. The real Value of an Optimization Center

What is the actual added value an OC brings to a development process? The benefit lies within the detailed

knowledge of the OC team, in a profound prediction of the consequences of decisions that need to be made early

in the development process and in the standardized approach of an OC. Properly applied, the OC will check the

outcome of the options that have to be evaluated as early as possible and detects the available weight reduction

potential. All suggestions the OC makes will consider the robustness of the predictions. An OC will constantly

work with the customer’s engineering staff to streamline methods and processes.

CAE Weight Management Support offers an improved understanding of the development progress, as the results

of the CAE analysis and the intensive exchange with weight functions will provide the project management with

predictions concerning performance, cost, and timing. As the project management is able to react earlier to

erroneous development directions and can lead the project into the desired direction, development risks are

minimized.



Page - 7

8. Implementation Examples

Successful implementations of optimization centers are found in both the Aerospace and Automotive industries.

The aerospace industry has led the way and OCs has been successfully established both at Boeing [3] and at

Airbus [4] in recent years.

A/C

Subsystem 1

Part 1.1

Part 1.2

A/C ConceptBaseline

SubsystemArchitecture

Part config.

MDO andGlobal Sizing

OptimizationDriven ConceptDesign

OptimizationDriven Design

MDO andGlobal Sizing

OptimizationDriven Design

A/C Level

Part

Optimization DrivenConcept Design

Sub-system

Subsystem arch itectureFeasibilityPreliminary mechanical propertiesPreliminary definition of parts

Requirements and specs.Design spaceBound ary conditions

Detailed p art configurationDetailed mechanical propertiesStress report

Requirements and specs.Design spaceBound ary conditions

Figure 9: Optimization Strategy used in the Aerospace industry.

Figure 8 shows how optimization can be used at different development levels in the Aerospace industry. In the

current OC implementations, the work is mainly performed on subsystem and on parts level.


Geometry Extraction


Package Space Definition


Material Layout

Automatic optimum sizing

Buckling and StressPrototype

Figure 10: Optimization Process for Substructures as executed in an Optimization Center

As a comparison, the automotive industry has adopted the concept of OCs during the last two to three years.

Three automotive Optimization Centers have been established recently in Europe:



Page - 8

Renault [5]: Power Train Optimization Centre - The optimization centre applies KPI (key performance

indicator) analysis in order to screen and select part and systems for optimization in a structured

manner. Optimization is performed on parts from both the standard development process, from

concept development and from research projects.

OEM 2: Body-in-White Optimization Centre - Focused on optimization driven concept design.

Investigation on big BIW sub-structure has shown a high confidence estimate of 15 – 20 %

weight reduction on that particular structure. The new layout show new unique features to the

design. Center is expanding.

OEM 3: Body-in-White Optimization Centre - Center hooked up high in the development organization and

works with part and substructure optimization on multiple platforms. Weight opportunities in

range of 10 % of investigated parts identified.

Figure 12: Idealized optimization centre structure for OEM 3

Programme

Centre Manager (Weight Team)




Senior Optimisation Expert

Optimisation Expert(s)

Weight Manager

Attribute D epartment Leaders

CAE Process Manager

Customer (Programme)

Owner – VP Product Development

In-House

Optimisation Centre

Steering Committee

Optimisation Lead

Consultants

Software Developers

Process Experts

Expert Consultants



Page - 9

9. Summary and Outlook

To receive profitable material savings and to truly meet CO2 emission targets and internal cost targets, weight

goals consequently have to be followed up even more intensively. Based on the Optimization Center concept, an

OEM can be supported to reach weight reduction goals with several levels of integration. The OC finds the

weight potential, combines them with the necessary changes of material and requirements on production

processes, and enables the assessment of cost and value. For existing weight management functions at the OEM,

the CAE Weight Management Support program is a valuable addition to enhance the knowledge for weight

related decisions within the OEM. To exploit the maximum potential of weight reduction, it is important to

include the OC as centrally as possible within the product development team, to have explicit support from

program management and to deploy optimization as early as possible. But even if implemented at a later point in

the development process, an OC can still deliver significant successes.

Current optimization center implementations show that the OC environment provides focus and momentum to

maximize the benefits of optimization for the product design. The OC execution model provides an opportunity

to integrate the optimization technology into existing standard product design processes. The OC execution

model additionally provide an excellent environment to improve, verify and release methods and processes whichlater can be used on a broader basis within the OEM. Thus, the OC is a center of excellence where best practice

is developed, educated and executed.

References:

[1] Lutsey, N., 2010. Survey of Vehicle Mass-Reduction Technology Trends and Prospects. PowerPoint

Presentation, El Monte, California.

[2] Bjelkengren, Catarina, 2008. The Impact of Mass Decompounding on Assessing the Value of Vehicle

Leightweighting. Thesis Dual Degree of Master of Science, Massachusetts Institute of Technology.

[3] Amorosi; Steve, 2006. Application of Topology, Size and Shape Optimization on the 787 Wing Leading

Edge Structure. HyperWorks Technology Conference.

[4] Marasco, Andrea-Ivan 2010. The Airbus A350XWB Optimization Centre: An Optimization Deployment

Model. European HyperWorks Technology Conference.

[5] Hähnel, Anthony, 2011. Introduction of Weight Management Technology into an Established Design

Process. Altair Event, New Technology, New Engineering Delivery Models.

optimization centers a systematic deployment of structural optimization in large enterprises

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