Castellated steel beams under impact load

This study explored the impact of irregular dynamic loads on castellated steel beams (CSBs) by conducting drop weight impact tests and establishing a numerical model using the nonlinear finite element method. The numerical simulation results were compared with the test results of the impact to verify its validity and analyze the buckling process and stress development of the CSB under impact load. Results showed that during the impact process, the maximum shear force was achieved first, followed by maximum bending moment and maximum deflection, respectively. It was observed that the increase in impact velocity and impact mass were unfavorable to the deflection of the CSBs, and resulted in an increase in the time required to dissipate impact energy. Furthermore, the ratio of spacing between openings to beam height exhibited a minor impact on the deflection in the range of 1.083-1.75. The ratio of opening height to beam height mainly affected the deflection near the midspan of the CSBs in the range of 0.5-0.7. The impact location significantly influenced the shape of the deflection curve. The larger the span-height ratio was, the more unfavorable it was for the CSBs to resist the impact. In addition, while the clamped support boundary condition reduced CSB deflection, it resulted in a rather substantial bending moment at the CSB ends. Based on the support rotation value as the damage evaluation index, a damage assessment curve with impact velocity and impact mass as the main control parameters was established.