Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
European Journal of Mechanics – A/Solids, Volume 33, May–June 2012, Pages 67-74
J.H. Hattel, K.L. Nielsen, C.C. Tutum
Department of Mechanical Engineering, Manufacturing Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
Abstract
The post-welding stress state, strain history and material conditions of frictionstir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence the weld performance. The objective of this paper is to discuss some of the main conflicts that arise when taking both the post-welding material conditions and stress–strain state into account in a subsequent structural analysis. The discussion is here based on a preliminary numerical study of the possible effect of the post-weldingconditions when subjecting a frictionstirweld to loading transverse to the weld line. The numerical model of the frictionstir welded joint, employs a step-wise modeling approach to combine an in-situweldsimulation with a post-weldingfailure analysis. Using the commercial software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is made by mapping the post-welding stress–strain conditions predicted in ANSYS to the in-house code by using re-meshing techniques. The study indicates a noticeable influence of the post-welding stress–strain condition when subjecting the welded plate to tension. E.g. an increase of the tensile curve prior to plastic flow localization was observed, with a substantial influence on the specimen elongation at the onset of localization and thereby failure. This influence is, however, shown to be strongly affected by the applied boundary conditions. Specimens cut from the welded plate, transverse to the weld line, showed the largest influence of the post-weldingconditions, even though significant relaxation of the residual stress state was predicted.
