爆破振动作用下砌体房屋结构动态响应与损伤分析

摘要

A three-dimensional solid model was built for an authentic four-storey masonry building,and the in-herent frequency and vibration mode were obtained by modal analysis.The dynamic response and damage of masonry structures under blasting vibration were analyzed with ANSYS/LS-DYNA.The calculation results indicate that the degree of structural response increases with the increasing of velocity amplitude,diminishes with the increasing of fre-quency.Under the effect of blasting vibration,the stress concentration produced on the first floor at the corners of the door and window,and horizontal cracks were formed accordingly.But the largest inter-storey drifts were lower than the masonry structural design code control values,which show that structure suffers brittle failure due to tensile stress.A conclusion can be drawn that it is not accurate to evaluate building's damage under blasting vibration with earthquake engineering evaluation criteria such as ductility and inter-storey drift angle.%以实心砌体房屋为研究对象,建立了四层砌体房屋仿真模型,应用有限元软件ANSYS/LS-DYNA通过模态分析获取其固有频率及振型,根据模态分析结果设计非一致爆破地震波激励加载模型,分析砌体房屋在爆破振动作用下动态响应和变形特点.计算结果表明:结构响应随地震波振速幅值增大而增大,随主频的增大而减小;爆破地震波作用下底层门窗角落易形成集中应力而产生水平裂缝,但砌体产生破坏时其最大层间位移均未达到砌体结构设计规范控制值和各类文献建议值,说明结构是由于受拉导致的脆性破坏.由此可见,采用延性、层间位移角等地震工程常用的结构损伤评估指标来评价爆破地震对建筑物的破坏是不准确的.