Investigation on Behaviours along Weak Axes of Steel Beam under Low Velocity Impact Loading: Experimental and Numerical

Abstract

This study examines the behaviors of structural members in their most vulnerable state (fixed along their weak axes) against sudden loads such as impact loads. To do so, eight supported rectangular hollow steel beam samples were constructed, and a circular head hammer weighing 75 kg was dropped as a free fall along the weak axes of these beams. Each fall had a different drop height (ranging from 250 mm to 2000 mm) and different amounts of energy (ranging from 183 J to 1471 J) in order to compare the structural behaviors of the beams against low velocity impacts with different drop heights and energy levels. Additionally, finite element analyses were conducted to investigate the performances of the rectangular hollow steel beams against impact loading along the weak axes numerically as well as experimentally. Initially, six model verification and mesh convergence analyses were performed to determine the optimum mesh size. After that, eight finite element models were developed with verified data in order to calculate the displacements, accelerations, plastic denting values, distributed stresses, and plastic equivalent strains. Consequently, impact load factors for static analysis were calculated mathematically and compared with the experimental and numerical results. Overall, the results obtained from the FE analyses were in line with the results obtained from experimental and mathematical studies. To sum up, the increases in the drop height of the impact force and the amount of energy in beams placed along their weak axes will increase the amounts of acceleration, maximum deflection, internal stress, residual displacement, and plastic denting in such beams.