基于几何参数的优化对双层柱面网壳结构动力性能的影响

Effect of Optimization Based on Geometrical Parameters on Dynamic Performance of Double-Layer Cylindrical Shell

以双层柱面网壳为研究对象，采用参数化设计语言APDL对ANSYS进行二次开发，实现了任意跨度双层柱面网壳的自动建模、加载、施加约束及求解。借此平台对柱面网壳结构进行模态和地震反应分析。首先，分析了结构自振特性随几何参数变化的特点，研究了结构的基频随矢跨比和网壳厚度的变化规律，结果表明，当矢跨比在1／3．6～1／5该范围内，结构的整体刚度较大；网壳厚度在1，8～2．1m时，网壳整体刚度较大；对于矢跨比一定的网壳，随着厚度的增加，杆件的动内力大多增加，横向弦杆的二维与单维动内力比值有所增加，而纵向弦杆的二维与单维动内力则变化不大。然后，对网壳进行不同几何参数下的地震反应分析，给出了最大节点位移和最大杆件轴应力随几何参数变化的时程响应曲线，揭示了这类网壳的地震反应特点。

Double-layer cylindrical shell was studied. ANSYS was secondarily developed by APDL, and automatically modeling, loading, adding constraints and solving of double-layer cylindrical shell with random span have been carried out. Mode and transient analysis has been analyzed based on it. The characteristics of structural natural vibration was firstly analyzed according to geometrical parameters, and natural frequency＇s rule of structure has been studied according to ratio of rise to span and shell thickness. The result show that the stiffness is larger when ratio of rise to span is between 1/5 to 1/3.6 and thickness is among 1.8 m to 2.4 m; Dynamic internal force of bars will increase along with increasing thickness and constant ratio of rise to span, and the dynamic internal force ratio of two-dimensional to one-dimensional also increase more or less, but the bar＇s force in longitudinal direction changed insignificantly. Time response curves of maximal displacement and axial stress have been drawn under seismic effect, and seismic performance of the shell has been derived.