初始几何缺陷对网壳结构线性动力反应的影响初探

摘要

The phenomenon of mode localization will be induced by the intensive distribution of natural frequencies and inevitable initial geometrical imperfections for reticulated shell structures, and mode localization will induce structural vibration localization. The induction factors of mode localization are analyzed by the matrix perturbation theory. The size and distribution pattern of initial geometrical imperfections are discussed and determined. Using a single spherical reticulated shell as an example, structural linear dynamic response under the same grotnd movement are calculated and analyzed by considering 50 groups of different initial geometrical imperfections. The results show that: initial geometrical imperfections can make linear dynamic response of reticulated shell structures change remarkably, so it should be considered adequately in the seismic calculation of reticulated shell structures.%自振频率的密集分布和不可避免的初始几何缺陷,将导致网壳结构出现模态局部化现象,而模态局部化将导致结构振动呈现局部化.通过矩阵摄动理论分析并给出了模态局部化现象发生的诱因,讨论并确定了初始几何缺陷的大小和分布模式.以一个单层球面网壳为例,进行了同一地面运动激励下,50个包含不同初始几何缺陷网壳结构的线性动力反应分析,结果表明,初始几何缺陷对网壳结构线性动力反应的影响是不可忽略的,建议在网壳结构的抗震计算中予以重视.