基于多尺度模型的RC框架撞击倒塌响应数值分析

为了在保证计算精度的同时提高撞击荷载作用下RC框架结构连续倒塌分析的计算效率，本文基于有限元软件LS-DYNA，建立了撞击响应分析的多尺度模型。针对该模型分别采用拆除构件法和撞击全过程分析法分析了撞击荷载下框架结构的连续倒塌动力响应。结果表明：拆除构件法在分析撞击作用下结构的连续倒塌时，由于忽略了撞击力及其对周围结构造成的初始损伤、初始位移和初始速度，低估了结构的动力响应，不能合理反映撞击作用下框架结构的破坏模式；多尺度模型能够准确模拟撞击作用下框架结构的动力响应和破坏模式，同时计算时间仅为精细模型的三分之一，满足整体结构系统撞击倒塌分析的需要。

NUMERICAL ANALYSIS ON THE COLLAPSE REPONSE OF A RC FRAME SUBJECTED TO IMPACT LOADING BASED ON MULTI-SCALE MODEL

In order to guarantee the accuracy and improve the computational efficiency of numerical analysis on the progressive collapse of the RC frames under impact loading, a multi-scale finite element model is established based on the finite element software LS-DYNA. The structural progressive collapse response of a RC frame subjected to impact loading is analyzed by using the alternative path (AP) analysis and the impact analysis respectively. The results show that the structural dynamic response is underestimated and the wrong collapse mode is obtained via the AP method in which the impact loading and its consequences, i.e. the initial damage, displacement and velocity of the structural members adjacent to the impacted column, are neglected. On the other hand, the dynamic response and the damage mode of the RC frame can be accurately simulated via the multi-scale finite element model with high computational efficiency. The computation time when using the multi-scale model is only about one third of that by using the detailed model which is suitable for the impact analysis for the entire structural systems.