Numerical analyses on steel beams with fin-plate connections subjected to impact loads

• The paper presents study of progressive collapse of steel frame subject to falling floor impact.
• The accuracy of numerical model is validated against previously reported tests.
• Energy is proposed to evaluate the structural resistance in impact analyses.
• The influences of many factors on dynamic behavior and impact resistance are studied in the paper.

This paper focuses on the dynamic behavior of steel beams subjected to falling floor impact loads, and fin-plate connection was used to connect beams and columns. ANSYS/LS-DYNA was employed to establish detailed 3D finite element models (FEM). The accuracy of finite element models was validated against experimental results. Simulation results indicate that the deflection angle of drop weight significantly affected maximum impact force. In addition, six groups of numerical simulations were conducted to study the influence of different parameters on dynamic behavior and impact resistance. The parameters included impact energy, impact location, strength of material, imposed load, distance of bolt holes and thickness of fin-plate. Energy dissipation, maximum displacement, distribution of plastic deformation and internal force at joints were compared in each numerical group. Parametric studies suggest that energy can be used to evaluate the structural resistance of steel beams in impact analyses. Steel beams show different dynamic behaviors under a certain impact energy but different impact masses and impact velocities. A higher impact velocity can slightly improve the energy dissipation rate. Steel beams develop different impact resistances while impact loads are applied at different locations. Besides, high-strength materials are beneficial to reduce the maximum displacement. Inertial effect plays an important role in dynamic behavior. Moreover, decreasing the distance between steel bolts and the thickness of fin-plate may cause premature failure of specimens under lower impact loads.