考虑材料损伤累积单层柱面网壳在强震下的失效研究

采用考虑钢材损伤累积的本构模型,对跨度15米单层柱面网壳在强震下的失效进行了系统的研究。在大量算例的基础上,考察了屋面质量、矢跨比、初始几何缺陷和长宽比等结构几何参数的变化对柱面网壳失效特征和失效极限荷载的影响,探讨了结构的强震失效模式及失效机理。对大量强度破坏算例在失效时刻的特征响应进行统计分析,建立了考虑材料损伤累积的单层柱面网壳动力损伤模型,可对结构在不同荷载强度下的损伤程度进行评估;提出了单层柱面网壳强震失效判别准则,用于判别单层柱面网壳在强震下的失效极限荷载。

Failure of single-layer reticulated cylindrical shells subjected to earthquakes

This paper addresses the study on failure mechanism of single-layer reticulated cylindrical shells subjected to severe earthquakes.Two failure modes,the dynamic instability collapse of single-layer reticulated cylindrical shells subjected to severe earthquake and strength failure resulted from excessive development of plastic deformation are described.With the consideration of the damage accumulation of steel material realized according to user subroutine(UMAT) of FEA program ABAQUS,a comprehensive numerical analysis of some single-layer reticulated cylindrical shells is carried out with the following primary parameters:different dead loads on the roof,initial geometric imperfection,and various geometric or structural parameters,such as rise-to-span ratios,length-to-width ratios.The failure characteristic and the ultimate load of single-layer reticulated cylindrical shells subjected to severe earthquakes are described,and the response regularity and failure mechanism with the change of analytic parameters are discussed.According to characteristic responses of single-layer reticulated cylindrical shells at strength failure state,the damage model indicating damage level of reticulated shells is fitted.The seismic failure criterion based on the damage model is proposed,which is used to distinguish the ultimate load of earthquake failure.