Characterization of dynamic tensile and shear strength of safety bolts in light collision safety devices of a train

Abstract

This paper introduces design strategy to develop safety bolts in the light collision safety devices under dynamic tensile and shear loading conditions. The light collision safety device is an energy absorbing one for low speed collision of a train. An energy absorbing scenario in the device has several sequential stages. Tension and shear bolts are the key components which make the sequential energy absorbing scenario operated by a series of failures at the specific collapse load. Exact failure loads of tension and shear bolts at crash conditions were determined in aid of finite element analysis considering the dynamic material properties of component materials. Failure loads of tension and shear bolts designed were verified with experiments using tension and shear type jig sets at quasi-static and dynamic loading conditions. Strain gages were attached to both the parallel section of tension bolts to measure the load response acting on tension bolts and the jig set to measure the load responses acting on shear bolts. The quasi-static and dynamic experiments as well as the numerical analysis explained above predicted the load capacities of tension and shear bolts accurately for the crashworthiness design.