Research On Numerical Simulation Of Collision Of Falling-beams And Structures During Earthquake

It has been proved by many damage investigations of devastating earthquakes that, the genesis of great property losses and casualties lies in the structure damage,and impact is an important factor resulting in the structure damage. So study of structure impact has been promoted to an important topic in seismic engineering. In order to avoid collapses and control collisions, structure impacts must be studied. This paper makes such an attempt, which is limited to collision of falling-beams and structures during earthquake.There are two major difficulties in numerical simulation of structure impact: the selection of impact model and the establishment and solution of dynamic equation for impact system. By summarizing the existing data of research on impact, the paper introduces the cogency of various models and selects Hertz-damp model, which can account for non-linearity associated with impact as well as the energy dissipated during collision. First, the mode superposition method, which can solve the elastic problem exactly, is used to build the dynamic equation for collision of seismal falling-beams and structures after introducing Hertz-damp model. The cogency of Hertz-damp model is well validated by comparisons with existing date after numerical solving the equation with Duhamel integral. Then, based on finite element method, constraint conditions on displacement imposed by collision are deduced, and the dynamic equation for impact system of general structures can be established finally. As for the large displacement and small rotation problem of free member, the paper applies the hybrid algorithm of rigid body motion and finite element, and gains simply visual results of collision of seismal falling-beams and structures through program.By research on collision of falling-beams and structures during earthquake, the paper provides methods and theories for study of structure collapses and some reference suggestions for reduction of earthquake disasters.