Technical Paper
Multiaxial Fatigue Criteria for Spot Welds
1992-02-01
920668
One of the problems commonly associated with fatigue life prediction of various spot welded geometries has been the need to test each geometry. Various high strength low alloy and low carbon spot welded specimen geometries have been tested. Even for the same nugget diameter, specimen width and sheet thickness, the fatigue resistance in terms of the either the maximum or range of remote load differed from one specimen type to another. This could be attributed to the fact that the weld nugget region is associated with multiaxial stress fields, which are neglected in the remote load analyses. An initial attempt to incorporate multiaxiality involved converting remote loads into nominal stresses in the vicinity of the spot weld using geometrical factors such as nugget eccentricity. Findley's parameter, a shear based multiaxial critical plane approach, was employed to evaluate the fatigue performance of the various geometries.