随机初始缺陷对单层球面网壳承载力的影响研究  

RESEARCH ON EFFECT OF RANDOM INITIAL IMPERFECTIONS ON BEARING CAPACITY OF SINGLE-LAYER SPHERICAL RETICULATED SHELL

作　　者：李会军[1] 王超[1] 韩健 LI Huijun;WANG Chao;HAN Jian(College of Water Resources and Architectural Engineering, Northwest A＆F University, Yangling 712100, China)

机构地区：[1]西北农林科技大学水利与建筑工程学院

出　　处：《工业建筑》2018年第4期112-119,143,共9页Industrial Construction

基　　金：国家自然科学基金项目(51408490)

摘　　要：单层球面网壳属缺陷敏感型结构。为研究杆件初弯曲、节点偏差及二者耦合作用对单层球面网壳整体稳定承载力的影响,首先推导了实现杆件初弯曲的相关算式,并阐述了其有限元实现方法;然后采用3种建模方法,分别研究了随机杆件初弯曲、随机节点偏差及二者耦合作用对网壳稳定承载力的影响程度。计算结果表明：随机杆件初弯曲对网壳的稳定承载力有显著影响,与理想网壳相比,当δ=l/1 000（l为杆件长度）时,极限荷载平均下降了约16.3%,且服从正态分布;随机节点偏差越大,网壳的极限荷载越小,离散性越大;杆件初弯曲与节点偏差耦合作用对网壳稳定承载力影响显著,对于所考虑的最大初弯曲幅值与节点偏差,极限荷载下降了17.8%~27.2%;权衡精度与计算量,研究具有杆件初弯曲网壳的稳定承载力时,宜采用8~10根等代直梁等代每根初弯曲杆件。Single-layer lattice shell is sensitive to imperfections. To research the influence of random initial curvature of members,joint imperfections and their coupling on bearing capacity of single-layer lattice shell,formulas for Kiewitt shell with random initial curvature of members were firstly derived,and realization methods of these formulas in finite element software were gradually illustrated. The influence of random initial curvature of members,joint imperfections and their coupling on bearing capacity of lattice shell were researched by using three modeling procedures. The numerical results were concluded as follows： the bearing capacity of reticulated shell was affected evidently by random initial curvature amplitude of members; compared to ideal lattice shell,the bearning capacity declined by 16. 3% and obeyed normal distribution when δ = l/1 000（l is member length）; the bearing capacity declines and its standard deviation increased when the joint deviation increased. The coupling effect of initial curvature and joint deviation remarkably influenced the bearing capacity of shell,and the bearing capacity declined by 17. 8% ~ 27. 2% for mentioned random imperfections; considering accuracy and computation effort,8 ~ 10 straight beams were feasible to substitute member with initial curvature when computing bearing capacity of shell.

关 键 词：球面网壳 稳定承载力 杆件初弯曲 节点偏差 随机缺陷 

分 类 号：TU399[建筑科学—结构工程]