基于应变能密度的单层球面网壳结构失效判定准则

Criterion for judging failure of single-layer latticed dome based on strain energy density

进行基于应变能密度的单层球面网壳地震作用下工作行为分析,意在给出一个合理且较为精确的判断结构动力失效准则。首先,对理想单层球面网壳结构的对数应变能密度(LSED)、以及有初始缺陷的单层球面网壳结构的指数应变能密度(ESED)与加速度幅值(A)关系进行理论推导,给出单层球面网壳应变能密度的表达式,奠定判定其失效的理论基础。然后,应用通用有限元程序对典型单层球面网壳在地震荷载作用下的动力反应进行全过程响应分析,并时时提取出各级动荷载幅值下的所有单元的应变能密度。进而,进行结构应变能密度走向特征分析,揭示单层网壳结构的整体塑性应变能密度积累到一定程度时,结构应变能密度-地震加速度幅值曲线产生转折点。最后,据此特征提出基于结构能量密度的失效荷载判定准则,并与现有判定准则进行比较。

In order to establish a reasonable and accurate criterion for judging the structural dynamic failure load, the working behavior of single-layer latticed dome under seismic loading is studied based on the structural strain energy density. Firstly, the expressions of the logarithmic strain energy density （LSED） for the ideal dome and the exponential strain energy density （ESED） for the dome with original defect related to seismic acceleration amplitude （A） are deduced. This provides a theoretical foundation for judging the failure load of single-layer latticed dome. Then, using the finite element general program ANSYS, the whole seismic response process of typical single-layer latticed domes is calculated and simultaneously the strain energy density of all elements is extracted. Next, it reveals that the structural LSED/ESED-A curve will produce a turning point once the structural strain energy density increases to a certain degree. Finally, a new criterion for judging the seismic failure of single-layer latticed dome is proposed based on the structural ESED-A curve feature and compared with the existing criterion.