fea projects lecture

8/12/2019 FEA Projects Lecture

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Major Steps in an FEA ProjectMajor Steps in an FEA Project1.1. Address the initial questions: Address the initial questions:

a.a. Do I really need the FEA?Do I really need the FEA?b.b. Can I use the previous test results or previousCan I use the previous test results or previous

c.c. Is this a standard design, so no analysis isIs this a standard design, so no analysis isnecessary?necessary?

d.d. Are loads, restraints (constraints) and materialAre loads, restraints (constraints) and materialproperties known well enough to make FEAproperties known well enough to make FEAworthwhile?worthwhile?

e.e. Would a simplified analytical model beWould a simplified analytical model besufficient?sufficient?


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f.f. Does my customer demand FEA?Does my customer demand FEA?g.g. What shall I do with the results of FEA?What shall I do with the results of FEA?

h.h.Do I have enough time to implement theDo I have enough time to implement theresults of the FEA?results of the FEA?

i.i. Should the analysis be done inShould the analysis be done in- -house, orhouse, orshould it be contracted out?should it be contracted out?

.. k.k. Do I have enough time and resources inDo I have enough time and resources in- -househouse

to do a completed FEA before designto do a completed FEA before designdecisions must be madedecisions must be made

l.l. Is inIs in--house expertise available?house expertise available?m.m. Is my FEA software what my customer wantsIs my FEA software what my customer wants

me to use?me to use?


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2.2. Establish the scope of analysis: Establish the scope of analysis:

a.a. Is it a standard analysis of a new product fromIs it a standard analysis of a new product froman established product line?an established product line?

b.b. Is it the last check of a productionIs it the last check of a production- -ready newready newdesign before final testing?design before final testing?

c.c. Is it a quick check of a design in progress toIs it a quick check of a design in progress toassis he desi ner?assis he desi ner?

d.d. Is it an aid to an R&D project?Is it an aid to an R&D project?e.e. Is it a conceptual analysis to support a designIs it a conceptual analysis to support a design

at an early stage of development?at an early stage of development?f.f. Is it the simplified analysis to help in making aIs it the simplified analysis to help in making a

design decision?design decision?g.g. What are the estimated number of modalWhat are the estimated number of modal

iterations, load cases, etc?iterations, load cases, etc?


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3.3. Establish a cost Establish a cost- -effective modelingeffective modelingapproach and define the mathematicalapproach and define the mathematicalmodel accordingly.model accordingly.

4.4. Create an FE model and solve it. MeshingCreate an FE model and solve it. Meshingand solution are largely automated stepsand solution are largely automated stepsbut still require input, which depending onbut still require input, which depending onthe software used ma include: the software used ma include:

a.a. Element type(s) to be usedElement type(s) to be usedb.b. Default element size and size toleranceDefault element size and size tolerancec.c. Definition of mesh controlsDefinition of mesh controls

d.d. Type of mesher to be usedType of mesher to be usede.e. Type of solver to be usedType of solver to be used


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5.5. Evaluate the results.Evaluate the results.a.a. Study the overall mode of deformations and animateStudy the overall mode of deformations and animate

deflection to verify restraints definition.deflection to verify restraints definition.b.b. Check for rigid body modesCheck for rigid body modesc.c. Check overall stress levels (order of magnitude) usingCheck overall stress levels (order of magnitude) using

analytical methods to verify applied loadsanalytical methods to verify applied loadsd.d. Check reactions using freeCheck reactions using free- -body diagramsbody diagrams

.. f.f. Analyze stress concentrations and mesh ability toAnalyze stress concentrations and mesh ability to

model them properly.model them properly.g.g. Review the results in difficultReview the results in difficult- -toto--model locations suchmodel locations such

thin walls and high stress gradients.thin walls and high stress gradients.h.h. Investigate the impact of element distortions on theInvestigate the impact of element distortions on the

data of interest.data of interest.


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6.6. Analyze the results.Analyze the results.a.a. Present deformation resultsPresent deformation resultsb.b. Present modal frequencies and associatedPresent modal frequencies and associated

modes of vibrationmodes of vibrationc.c. Present stress results and correspond factorsPresent stress results and correspond factorsof safetyof safety

.. structure to eliminate excessive stresses andstructure to eliminate excessive stresses andto improve material utilization andto improve material utilization andmanufacturabilitymanufacturability

e.e. Discuss results and repeat iterations until theDiscuss results and repeat iterations until theacceptable solution is foundacceptable solution is found


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FEA ReportFEA Report

Reports should be self explanatory andReports should be self explanatory andshould contain all information necessaryshould contain all information necessaryto analyze the results and to recreate theto analyze the results and to recreate the

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The following are major components of a typicalThe following are major components of a typicalFEA report and its contents:FEA report and its contents:Executive summaryExecutive summary

Objective of the project, part number, projectObjective of the project, part number, projectnumber, essential assumption, results andnumber, essential assumption, results andconclusions, software used including softwareconclusions, software used including softwarerelease, information on where the projectrelease, information on where the project

ac up s store .ac up s store .IntroductionIntroductionDescribe the problem. Why did it require FEA?Describe the problem. Why did it require FEA?

What kind of FEA was used (e.g static, contactWhat kind of FEA was used (e.g static, contact

stress, vibration analysis?) What were the datastress, vibration analysis?) What were the dataof interest? of interest?


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Load and RestraintsLoad and RestraintsDescribe the loads and restraints, inlcude loadDescribe the loads and restraints, inlcude load

diagram (eg FBD) discuss any simplificationsdiagram (eg FBD) discuss any simplifications

and assumptions.and assumptions.Model GeometryModel Geometry

Describe the model geometry and how it wasDescribe the model geometry and how it was

create e.g rom geometry n ntegratecreate e.g rom geometry n ntegrateCAD CAD- -FEA software, from CAD through anFEA software, from CAD through aninterface, created in FEA software); describeinterface, created in FEA software); describeand justify any geometry cleanup, defeaturingand justify any geometry cleanup, defeaturing

and idealization, justify the modeling approachand idealization, justify the modeling approach(eg solids, shells, beams)(eg solids, shells, beams)


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MeshMeshDescribe the type of element, global element size,Describe the type of element, global element size,

any mesh control applied, number of elements,any mesh control applied, number of elements,number of degrees of freedom, type ofnumber of degrees of freedom, type ofautomesher used and type of solver used,.automesher used and type of solver used,.Justify why this mesh is adequate to model theJustify why this mesh is adequate to model thedata of interest.data of interest.Analysis of ResultsAnalysis of Results

Present the displacement and stress results,Present the displacement and stress results,including plots and animations. Justify the stressincluding plots and animations. Justify the stressmeasure used to present results (eg maximummeasure used to present results (eg maximumprinciple stress, von Mises stress, maximumprinciple stress, von Mises stress, maximumshear stress). Discuss errors in the results, andshear stress). Discuss errors in the results, andpresent applicable safety factors consideringpresent applicable safety factors consideringanalysis errors. Discuss the applicability of theanalysis errors. Discuss the applicability of thesafety factor in use.safety factor in use.


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ConclusionsConclusionsMake recommendations to the requester regardingMake recommendations to the requester regarding

structural integrity, necessary modifications andstructural integrity, necessary modifications and

further study that might be needed. Recommendfurther study that might be needed. Recommenda testing procedure (eg strain a testing procedure (eg strain- -gauge test, fatiguegauge test, fatiguelife test). Make recommendation on futurelife test). Make recommendation on future

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