Evaluation and Validation of Bolt Shear Fatigue Under Constant Amplitude Sinusoidal Loading Through Simulations

This paper strives to obtain and validate fatigue life of hex head bolts in shear under constant amplitude sinusoidal loading. Paper focusses on developing a simulation methodology which will help identify bolts’ fatigue life in shear. Two case studies have been simulated using this simulation methodology. These case studies encompass variabilities with respect to connected joints, load paths, and distribution of moment of inertia. This paper also describes effect of bolt pretension and its effects on systems’ frequency which in turn derives shear stresses. Shear S–N curves are obtained from international journal of fatigue. The maximum shear stress dictates the fatigue life of fasteners with threads in shear plane. In the later part of the paper, simulation results are verified with physical tests. A very good correlation was obtained to consolidate the simulation methodology as a routine to understand the fatigue behavior of bolts under shear. Various useful conclusions have been drawn such as bolt shear prediction, vulnerability according to bolts’ position, and direction of excitation detrimental to structural integrity.