fatigue life evaluation of single and two riveted coach peel joints using strain- life criteria

In this paper, experimental investigation was performed to estimate fatigue life of single and double riveted coach peel joints of 2024 aluminum alloy. load controlled fatigue tests were conducted with load ratio and frequency of 0.1 and 10 hz, respectively. failure of the specimens revealed three major modes of folded region fracture (a-type), fracture from edge of the rivet hole (b-type) and mixed mode fracture (a & b). although all failure modes contributes equally in single riveted joint, mixed mode fracture was observed as dominant mode in two riveted ones. a numerical approach is applied to estimate fatigue life of riveted coach peel joints. finite element analysis was implemented by abaqus as the first step of this approach to estimate stress distribution, stress concentration factor, stress and strain amplitude. fatigue lives were then calculated using three fatigue life theories of monson-hirschberg, smith-watson-topper and morrow. finally, good accordance between numerical and experimental results revealed that the finite element approach combined with fatigue life theories is capable for fatigue life prediction. it is concluded that adding a rivet in longitudinal direction to the single riveted coach peel joint decreases the life cycles by increasing the stress concentration factor. moreover, results of finite element approach showed that monson-hirschberg and experimental data has the best agreement in compare with swt and morrow.