Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

Abstract

In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime.However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints.

Fatigue life evaluation of an ultrafine-grained pure aluminum

“…The S – N curve of notched specimen can be obtained by repeating this process for the applied remote load values. According to Figure 16, the volumetric method results were found to agree very well with the obtained results from experimental fatigue tests and presents good and reasonable results which were also reported in the literature 22,29,31,57 for different notched specimens, the multi-resistance spot welded joints and simple bolted plates. It can be concluded that the volumetric method provides a good prediction of the fatigue behavior of the notched components.…”

“…It should be noted that the fatigue life predictions via the volumetric method demonstrated good agreement with the experimental results of different notched components, spot welded joints, simple, and hybrid (bolted-bonded) double lap joints 28–31 and gives a relative good description of notch effect. In addition, the behavior of notched specimens was also studied by other researchers.…”

“…It is worth mentioning that in this method the average stress within the critical distance near the notch root is defined as the critical distance stress which is the main parameter in evaluating fatigue life via the volumetric method. 27 It should be noted that the fatigue life predictions via the volumetric method demonstrated good agreement with the experimental results of different notched components, spot welded joints, simple, and hybrid (bolted-bonded) double lap joints [28][29][30][31] and gives a relative good description of notch effect. In addition, the behavior of notched specimens was also studied by other researchers.…”

Weld arrangement effects on the fatigue behavior of multi friction stir spot welded joints

“…According to Ref. [24], the volumetric approach has been successfully employed for fatigue life assessment of the multi resistance spot welded joints. However, although the vital parameters of this method are finite element analysis and the values of fatigue strength reduction factor and fatigue life of smooth specimens, the essential prerequisite of this procedure is to realize the direction of the fatigue crack path of the notched specimens.…”

“…For example, Adib et al [23] and Hassanifard et al [24] looked into the fatigue life of multi-spot welded stainless steel joints by employing the volumetric method. In the present study, an attempt is made to investigate the arrangement effects on fatigue behavior of multi friction stir spot welded joints of aluminum 7075-T6 alloy.…”