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The Value of Early Analysis (Part 1)by Gregory Roth

Senior Engineering Specialist, Eaton Corporation Innovation Center, Detroit, Michigan

Business DriverOne of the driving forces inmanufacturing companies is thecontinuing demand for reduction inproduct development time and cost tomaintain profitability andcompetitiveness. Over the years, thisrequirement has promptedorganizations in a wide range ofindustries to find different ways ofmaking product development moreefficient. Advancements in the entire

spectrum of CAD/CAM/CAE tools inparticular have automated manydesign, engineering, and analysistasks to shorten development cycles,mostly as a labor savings to minimizeoverhead costs.

Progressive manufacturers are nowinvestigating ways to further reducedesign cycle-time by evaluating andchanging the product developmentprocess itself. The goal here is not so

much economic savings in theengineering department but rather abroad business advantage in gettingproduct innovations to customersfaster and thereby increasing acompanys market share. Efforts atthe Eaton Corporation InnovationCenter, for example, are being directedtoward studying the benefits ofdistributing analysis activitiesthroughout product developmentinstead of waiting to face designproblems just before a product isreleased to manufacturing.

Interactive Feedback ProcessOne approach now under investigationis called the interactive feedback CAD/CAE process, where basic analysistools for first-pass studies are tightlycoupled with CAD software. Thisallows designers and engineers toquickly iterate back and forth inperforming basic conceptual what-ifstudies to evaluate the merit of different

ideas, compare alternatives, and filterout design weaknesses before moredetailed analysis, prototype testing,and production planning.

Evaluation ImplementationPilot studies are underway using toolssuch as DesignSpace software fromANSYS Inc.. These tools are tightlyintegrated to different commercial CADpackages normally run by designersand engineers. Ongoing studies havefocused on components andassemblies manufactured by Eaton asa major supplier to the automotiveindustry, providing a wide range ofmechanical products such as

transmissions, differentials andclutches as well as completemechatronic systems including thosefor air management, valve sets andsuperchargers.

Case StudiesIn a redesign of a heavy duty trucktransmission, for example, engineersused up front CAE to conduct basicstress studies to minimize stresseson the transmission housing. The

program allowed for evaluation ofpossible design modifications of thegear mounts to weed out inefficientapproaches quickly and validatecorrect ones before tooling was built.The analysis indicated that designchanges originally proposed would nothave solved the problem and enabledengineers to soon find a suitable gearmount configuration, saving thecompany the cost of tooling, testing,and another redesign cycle.

In another project, interactive CAE wasused for analysis of a heavy duty truckclutch housing to evaluate stress/strain concentrations prior to empiricaltesting. This process quickly identifiedproblem areas early in the developmentcycle and enabled engineers to modifyand verify the design before tooling wasbuilt.

Work on the various pilot projects hasshown impressive savings. Using the

dynamic interactive CAD/CAEfeedback process has resulted in timeand cost savings ranging from 30% to50% in the CAD/CAE/CAM phase of

product development. Projects thatformerly took eight weeks of design andanalysis can now be completed in fourto five weeks, for example. Moreover,even greater savings can be achievedin the later stages of productdevelopment when designs passprototype testing the first time, thuseliminating costly and time-consumingiterations done to fix last-minuteproblems.

Key StrategyStreamlining the product developmentprocess using interactive feedbackCAD/CAE is part of Eatons continuingglobal strategic efforts to maintain itsstrong market leadership position byimplementing the most advanced toolsand processes for developinginnovative, quality highly-engineeredproducts. Eaton Corporation is a globalmanufacturer of highly engineeredproducts that serve industrial, vehicle,

construction, commercial andsemiconductor markets. Principalproducts include electrical powerdistribution and control equipment,truck drivetrain systems, enginecomponents, hydraulic products, ionimplanters and a wide variety ofcontrols. Headquartered in Cleveland,the company has 49,500 employeesand 155 manufacturing sites in 25countries around the world. Sales for1998 were $6.6 billion.

Automotive Supply Chain PressuresManufacturers in nearly all industriestraditionally have faced the samepressure to reduce time and costs whileimproving product quality andperformance. Primarily to achieve laborsavings, astute engineering managersand supervisors tried to squeeze all thework they could from their staffs to helpthe department bottom line. Shorternumbers of hours to create engineering

drawings, complete design projects,and get the product released tomanufacturing translated directly intolower costs. Similarly, initiatives with

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acronyms such as JIT, TQM, SPC,and CIM were used in manufacturingto minimize production time socompanies could move finishedproducts out the door as fast aspossible. Generally in the past, these

efforts were motivated by efforts toimprove Return On Investment (ROI)and increase profits by minimizingoverhead costs.

A growing number of companies nowrecognize that, although running atpeak operating efficiency is admirable,this alone does not guarantee successin the marketplace. Instead, a majorfactor now being focused on by manymanufacturers is time to customer,since market share is sooverwhelmingly determined by whogets to buyers first with productinnovations and features. A growingnumber of manufacturers nowrecognize that being late in releasingproducts has a direct correlation withlost market share. This trend isespecially strong in recent years withcustomer preferences changing sorapidly.

The impact of this trend has been felt

particularly in the automotive industryfor passenger cars as well as a varietyof over-the-road trucks and off-highway

vehicles including constructionequipment and agricultural machinery.The fiercely competitive nature of thesemarkets means manufacturersabsolutely must consider time tocustomer as a critical factor in doing

business, all while maintaining qualityof design and production. As a result,shortening the product developmenthas become not just a matter oftrimming time to save money but offinding major ways to radicallycompress the product developmentcycle for the survival of the company.Whereas automakers currently require48 to 37 months to develop a new carplatform, for example, their goal is tocompress this time to 24 months. (SeeFig. 1)

Supply Chain Re-EngineeringAt the same time this movement isoccurring, automotive OEMs are alsochanging the way they work withsuppliers such as Eaton. Led by themajor automakers, a growing numberof companies in many industries aredelegating increasing levels of designresponsibility to suppliers that formerlymade parts according to the OEMsspecifications. Suppliers are thus

being placed in the position ofconfiguring geometry, selectingmaterials, analyzing stresses,

evaluating reliability, and otheraspects of product development ofcomponents, assemblies andsubsystems based on performance,

function, and size. By allowingengineers at the Tier 1 and Tier 2 levelfocus on their areas of specializationwhile those at the OEM levelconcentrate on overall productintegrity, this approach increasesefficiency and improves designs.

Opportunity & Enhanced ResponseThis shift in design responsibility downthrough the supply chain presentssupplier companies with tremendousbusiness opportunities. But as more

and more product development isdelegated, pressure on suppliersincreases not only to create designsthat work properly but also meetincreasingly strict standards andrequirements. Moreover, deadlines forgetting designs completed andproducts delivered are tightened to giveOEMs time to review the suppliersconfigurations and ensure they all fittogether and function properly in theoverall end product. As a result, the

automakers goal of reducing productdevelopment time for the overall vehicleby half means suppliers often mustcomplete their work in less thanperhaps 25% the time formerlyrequired to design a vehicle assemblyor subsystem.

Tools for Product DevelopmentManufacturers have a wide range ofcomputer-based tools available tosupport the product development

process. Rapid prototyping systemsquickly convert CAD models intophysical prototype parts so users canhold, handle, fit together, and evaluatethe appearance of components.Knowledge-based engineeringcaptures technical standards,procedures, and other information insoftware to automate routine designtasks. Empirical testing systemsutilize state-of-the-art software-driveninput equipment for duplicating real-world conditions, sensor technology for

accurately measuring responses, andstatistical methods for interpretingresults. Solid modeling enables

Figure 1: The goal of many automotive manufacturers is to reduce product

development times by half.

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engineers to define parts andassemblies in 3D space and utilize thisgeometric and associated product datain a variety of downstream

applications. Computer-aidedengineering (CAE) includes simulationand analysis technologies includingfinite-element analysis (FEA) used tostudy stress, deformation, vibration,temperature distribution, and otherbehavior in structures.

These tools do not act alone in isolationbut rather work together in supportingthe product development process,much like the underlying pillars of abridge. Each has individual tasks and

defined areas, but all are necessaryfor the total support needed. No singletool can effectively solve the entireproblem, rather they all must be usedin conjunction with one another toshave excess time and expense fromthe product development process.

So work done with one tool mustalways be performed with the othersin mind. Otherwise, efforts are oftencounterproductive, delays are

introduced, and important benefits areoften negated. All the tools should beused in a coordinated manner to avoiddelays, redundant efforts, andinefficiencies.

Traditional Analysis BottleneckOf all the tools in the productdevelopment process, FEA is one ofthe most valuable in analyzingstructures to detect areas the mightundergo excessive stress,deformation, vibration, or otherpotential problems. Since the earlydays of the technology in the 1960sand 1970s, FEA has become one ofthe most widely used methods forstudying structural integrity.

FEA systems now have powerfulgraphics capabilities, automatedfunctionality, and advanced userinterfaces that make the technologyconsiderably faster and easier to use

compared to early programs. Theseimprovements notwithstanding,however, full-blown advanced FEA stillrequires considerable time and the

expertise of a dedicated analyst withthe knowledge necessary to applyproper mesh densities, element types,and boundary conditions. Theseexpert analysts also must know howto go about translating CAD geometry

into the proper format for building theFEA model as well as correctlyinterpreting plots and other outputinformation.

Because of the skills, training, andbackground required, therefore,experienced FEA analysts aregenerally in short supply and usuallycongregated in centralized groups thathandle analyses tasks for the entireorganization. Traditionally, engineersand designers develop partconfigurations and then throw thedesigns over the wall to the analysts,who then assign a priority to the projectand get to it when they can after otherwork is completed. Days, weeks ormonths usually go by before analystscan provide results andrecommendations.

In most manufacturing companies,this exchange between designers andanalysis is so slow and cumbersome

that FEA is typically reserved for criticalcomponents with identified risks. Forother components, it is applied in the

final phases of product development,often only if hardware has failed somestep of testing. Engineers thenreconfigure parts and send the newdesign back through the cycle again.

Such traditional build-test-fail cyclesexpend considerable time and effort inmodifying designs, changing drawings,issuing engineering changedocumentation, and getting appropriateapprovals. Also, designs may be farless than optimal due to quick-fixesinserted hurriedly to meet release-to-manufacturing deadlines. In manycases, parts may be overdesigned,resulting in added size, weight, andmaterials and increased manufacturing

complexity. And solving isolatedproblems late in development also maydetract from the overall design of theentire product.

Benefits of Up-Front Analysis

In efforts to shorten the productdevelopment cycle, manymanufacturers are re-orienting theprocess itself so that analysis isperformed much earlier in productdevelopment. This moves CAE forwardinto conceptual design where changes

are much more easy and economicalto make in correcting poor designsearlier.

Figure 2: Focusing greater analysis effort in the initial stages of

design avoids many problems later.

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Experience of manufacturers in manyindustries has shown that 85% of thetotal time and cost of productdevelopment are committed in the earlystages of product development, whenonly 5% of project time and cost havebeen expended. This is because in

the early concept stages, fundamentaldecisions are made regarding basicgeometry, materials, systemconfiguration, and manufacturingprocesses. Further along in the cycle,changes get harder to make.

Essentially, the time and cost tocorrect problems increase ten-fold witheach step of the product developmentcycle: concept definition, detaileddesign, prototype manufacture,prototype testing, and production. Soa relatively minor change not made inthe concept definition stage that wouldhave cost a few dollars could end upcosting hundreds of thousands ofdollars in the production stage, ormillions if flawed products are shipped.

One of the major benefits of up-frontanalysis is the ability to perform what-if simulations that enable engineersand designers to evaluate alternativeapproaches and explore options early

I the design cycle to arrive at a superiordesign. Through this process,engineers and designers can quicklyinvestigate many design variations and

evaluate numerous ideas that wouldnot be practical to test in hardware.Moreover, computer analysis helpsthem determine trouble sources thatotherwise would be extremely difficultto find in the jumble of complexinterrelated variables.

Caution Longer Design Phase !Because more resources are focusedin the early design stages, costsduring this phase will higher thantraditional initial stages of productdevelopment. Also, designs may takesomewhat longer to release asconcepts are being virtually proven outup front, rather that later by empiricaltesting. However, this added time andcost is more than offset later throughsavings in prototype testing and fewerengineering changes. (See Fig. 2)

The use of up-front CAE supports thecompression of the productdevelopment cycle by changing themanner in which errors are found andthe design refined. A typical effortwithout CAE is an iterative cycle inwhich the design is created, prototypesare made through soft tooling, and testsare run. In most initial testingsequences, parts usually fail, resulting

in another cycle of redesign, softtooling, and testing. This can berepeated numerous times untilsatisfactory performance is reached.

In using up-front analysis, CAD andCAE are jointly conducted in aninteractive feedback loop up-front inproduct development. As soon as a

basic CAD model is configured, apreliminary analysis is run and theCAD model modified and re-analyzeduntil it performs optimally. Ideally, theresulting prototype design wouldsuccessfully pass all empirical teststhe first time. (See Fig 3)

Alternative Implementations

To inject CAE up-front, somecompanies have attempted to dedicatea group of analysts to perform initialevaluation studies on designs in the

early stages of product development.Generally, these are relatively simplelinear-static analyses on individualparts that are done to find approximatein the ballpark answers. Basically,the intent at this stage is to filter outbad designs early. Then in the laterstages of design, analysts wouldperform more in-depth advancedanalysis involving nonlinearmultiphysics and dynamic studies.

The trouble with this procedure,however, is that analysts quicklybecome overwhelmed with performingthese rough conceptual studies inaddition to their already heavy workloadof full engineering analyses. Theresulting long delays defeat thepurpose of early analysis, promptingmany engineers to circumvent thesystem and forego up-front analysisentirely.

Eaton Corporations Innovation Center

is piloting some solutions to thisdilemma. Central to them is a relativelynew class of first-pass FEA that iseasy enough for designers andengineers to use themselves and istightly integrated with the CADsoftware they are using.

Editors Note:

In the next issue Greg Roth will look at

the criteria for selecting a sytem, theorganisational and cultural issues and the

metrics used to monitor performance

improvements. For organisationsconsidering similar strategies attending

the NAFEMS course The Fundamentals

of FEA for Design Engineers would be a

sound investment.

Figure 3: Up-front interactive CAE/CAD can streamline the product

development cycle by filtering out poor designs and perfromance

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