overview of weldment fatigue life...
TRANSCRIPT
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F. V. LawrenceUniversity of Illinois
At Urbana
Overview of Weldment Fatigue Life Prediction
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The fatigue-prone machine
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Lecturer
Professor Frederick LawrenceCivil and Environmental EngineeringUniversity of Illinois at [email protected]
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Outline
I IntroductionII Fatigue FundamentalsIII Fatigue ModelsIV Modeling Weldment Fatigue BehaviorV Predicted Weldment Fatigue BehaviorVI Classifications of WeldmentsVII Improving the Fatigue Life of Weldments
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Overall objective
To understand the factors which control the fatigue life of weldments.
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Underlying ideas…
No two weldments are alike!The fatigue of weldments is a complex, non-linearproblem.Weldment fatigue life is strongly dependent upon initial conditions.Models help us understand what may happen and how to control it!Fatigue is caused by the fluctuation of local stresses and strains.There is nothing more practical than a good theory!
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I Introduction
Fatigue of Weldments
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AM - Cracked Hsg 1
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AM - Front Axle
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AM - Rear weld overall
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AM - Front weld
AM 11/03 12AM - MVC
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What to do?Reduce the local stresses and strains.
Redesign componentReduce stress concentrations.
Avoid lousy weld geometries.Make the weld toes nice.Control weld distortions.
Avoid tensile residual stresses.Avoid high strength materials.
Calculate, don’t guess.Use fatigue life improvement techniques.