effect of sheet thickness on fatigue behavior of friction stir spot weld of al 6061-t6 lap-shear configuration

The effect of three different sheet thicknesses of friction stir spot welding on lap-shear specimens of al 6061-t6 alloy was experimentally analyzed. different fatigue life evaluation models were applied to estimate the fatigue behavior of the friction stir spot welding in different thicknesses. experimental results show a clear correlation between static strength and fatigue behavior of different welding conditions. results of tensile and fatigue tests demonstrated the sheets with 2mm indicated the optimum thickness which were studied in this research. at the same cycles, fatigue results of different thicknesses showed considerable differences in the low cycles in comparison with the higher ones. the evaluation models of pook, zhang and three-dimensional finite element models were investigated in the different sheet thicknesses. the three-dimensional finite element model evaluated fatigue behavior better than the other models at different sheet thicknesses.