Digital Repository, ECF15, Stockolm 2004

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Redistribution of stresses from manufacturing operations during service loads and the effect on fatigue life of built-up structures
L. Josefson, J. Ringsberg

Last modified: 2013-02-08


When manufacturing built-up structures different operations like joining, forming and castingwill introduce residual stresses, which will interact with subsequent service loads applied tothe structure and also influence growth of cracks in critical locations. This overviewaddresses the fatigue design of structures considering the effects of residual stresses causedby manufacturing.The redistribution of residual stresses during operation, the derivation of stress-intensityfactors for cracks in residual stress fields and techniques to study growth of cracks instructures containing residual stress fields will be discussed. Joining of components bywelding will be discussed in detail. Welding will introduce residual stresses in the structuredue to localized plastic deformation caused by strong temperature gradients, with normally,tensile peaks in the welded region where cracks often are initiated due to the stressconcentration. The presence of tensile residual, mean, stresses in regions with stressconcentrations make welds susceptible to fatigue crack growth, which has lead to thedevelopment of special design codes for welded joints. The background for such codes anddifferent strategies for the fatigue design will be addressed.Some recent applications will be discussed in detail, growth of cracks in spot welded carcomponents, in flash butt welded railway rails and in stress coined holes in plates.

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