The Mechanisms of Fatigue-Improvement Fasteners in High Quality Shear Loaded Joints

The mechanics whereby fatigue-improvement fasteners give rise to increased joint fatigue resistance is examined using the results of both analytical and experimental studies. The inferences of a brief review of the mechanisms of fatigue damage are used to demonstrate how each of the interference fit, cold work, and coupled cold work-interference fit systems improve fatigue resistance. Experimentally developed fatigue data for standard joint test configurations are then analyzed using the so-called critical location approach to fatigue life analysis. The results of this study are interpreted in the context of joint designs used in the automobile industry.