Visual Simulation Of Earthquake Collapse And Evacuation Of Building Structure And Occupants Casualty Assessment

The collapse of building structure often causes a lot of casualties and property losses.The collapse process under the action of huge earthquake has the characteristics of strong nonlinearity and media discontinuity.It is difficult to get the accurate result of structure collapse by theoretical analysis.Full scale or scale model test needs a lot of manpower,material and financial resources,while the finite element method can only give the judgment of building collapse,which is difficult to solve Because of the large deformation in the process of collapse,it is of great significance to realize the whole process simulation of structure collapse.Most of the existing simulation of people’s escape and evacuation under the action of earthquake adopts the "one size fits all" evacuation mode.Without considering the actual situation,the bottom members are often the first to collapse and damage,resulting in the outlet blocking,resulting in the phenomenon that people can’t continue to evacuate.The simulation results are quite different from the actual situation.After the collapse of the structure,if people can not be evacuated to the outdoor in time,it will cause casualties.Most of the existing assessment methods of casualties under the earthquake action are based on historical earthquake damage data or building vulnerability.These methods are mainly aimed at the rapid assessment of regional earthquake damage,which is not suitable for the refined assessment of casualties in a single building.In order to solve these problems,in Chapter 2,based on the basic principle of discrete element method,the building structure is divided into beam plate column elements,and the stress and deformation between elements are simulated by the connection of generalized constraint and spring constraint.Based on the physical engine bullet,the complex motion and collision process between discrete rigid bodies are calculated,and the real-time updating of the motion state of discrete rigid bodies is realized.The complete collapse process of the building is obtained,and the collapse mechanism of the structure is analyzed.In the third chapter,the shortcomings of the traditional social force model are analyzed firstly,and the social force model is improved by considering the influence of panic psychology and earthquake induced falling debris on the evacuation speed.Secondly,based on the improved social force model,the evacuation simulation considering the evacuation behavior is proposed to realize the evacuation of people in a single building when the earthquake strikes Process simulation.In the fourth chapter,based on the collapse process and debris distribution of the second chapter and the simulation results of evacuation in the third chapter,the refined assessment of casualties in a single building is given.The simulation results of this paper can be used to analyze and study the collapse mechanism of the structure under the action of earthquake and the anti collapse ability of the structure itself,find out the relatively weak layer of the structure and the distribution of the falling debris of the components induced by the earthquake in advance,provide guidance for the seismic design of the structure and the evacuation of the personnel,and realize the refined assessment of the casualties of the single building.In addition,compared with the traditional "one size fits all" evacuation simulation,the evacuation process in this paper is more consistent with the actual situation,and the simulation results are more real and accurate.