荷载非对称分布下单层球壳的动力倒塌振动台试验研究

DYNAMIC COLLAPSE OF SPHERICAL SHELL UNDER UNSYMMETRICAL LOAD DISTRIBUTION AND STUDY OF SHAKING TABLE TEST

为验证荷载非对称分布下网壳结构的动力倒塌机理,对一个单层球面网壳缩尺模型进行了振动台试验。选用三条地震波对网壳结构的动力特性、弹塑性阶段的动力响应(位移、加速度和应变等)、倒塌阶段的破坏过程进行了研究。通过ANSYS/LS-DYNA,以显式动力分析方法为基础,模拟了荷载不对称分布下网壳结构的倒塌全过程,并进行了倒塌机理的分析。结果表明,当网壳受半跨荷载时,形成塌陷区域的节点位于荷载作用区内,中部主肋屈曲产生了较大的动力效应并导致结构荷载作用区内局部塌陷形成、扩大使结构最终倒塌。有限元分析结果与实测结果吻合较好,验证了数值计算方法的正确性。

To understand the dynamic collapse mechanism of a spherical shell under an unsymmetrical load distribution, a shaking table test on a single-layer spherical shell was conducted. The dynamic characteristics of the spherical shell, dynamic response(displacement, acceleration and strain, etc.) and failure process due to both small and strong earthquake actions were studied through three seismic waves. By the Explicit dynamic analysis method in ANSYS/ LS-DYNA, the collapse process and mechanism under unsymmetrical loading distributions were carried out for the testing models. The result shows that the nodes of collapse area are in the loading zone under the unsymmetrical load distribution. Central main ribs buckling caused the larger dynamic effect and led to the formation of partial collapse, which were expanded and eventually led the building to be collapsed. The numerical model is also proved to be reasonable by comparing the theoretical and experimental results.