荷载初偏心对K6型网壳稳定性的影响研究  

Effect of Random Initial Load Eccentricity on Stability of K6 Reticulated Shell

作　　者：李会军[1] 饶颢 肖姚 LI Huijun;RAO Hao;XIAO Yao(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：《建筑钢结构进展》2019年第3期56-63,共8页Progress in Steel Building Structures

基　　金：国家自然科学基金(51408490);大学生创新创业训练计划项目(201710712046)

摘　　要：为研究荷载初偏心对单层球面网壳整体稳定承载力的影响,首先提出了初偏心荷载的施加方法及其在有限元程序中的实现步骤;接着以K6型单层球面网壳为研究对象(矢跨比f/L分别为1/3、1/4、1/5、1/6和1/7),考虑了5种荷载工况(满跨对称荷载,半跨非对称荷载p/G分别为0.75、0.50、0.25、0),系统地研究了不同初偏心荷载(μe分别为0、5mm、10mm、15mm、20mm、25mm、30mm和35mm)对网壳稳定承载力的影响规律;然后探讨了网壳在初偏心荷载作用下的失效机理。通过200例网壳算例分析,结果表明:对于矢跨比为1/4~1/7的网壳,随着荷载初偏心的增大,网壳的稳定承载力近似线性降低;当荷载初偏心较小时,满跨荷载作用下大矢跨比网壳的稳定承载力低于不对称分布的情况;当荷载初偏心较大时,情况正好相反。随着荷载初偏心的增加,矢跨比愈大的网壳,稳定承载力的降低愈明显,表明大矢跨比网壳对荷载初偏心更加敏感。提出的初偏心荷载施加方法与分析思路可推广至其它类型的空间网格结构中。To study the influence of random initial eccentric loads on the stability bearing capacity of reticulated shells,initial eccentric loads are applied on reticulated shells in finite element analysis.Then,considering five load cases(including full-span distributed load and asymmetric half-span distributed load,i.e.,p/G=0.75,p/G=0.50,p/G=0.25 and p/G=0),the influence of different random initial eccentric loads(μe=0,μ_e=5 mm,μ_e=10 mm,μe=15 mm,μe=20 mm,μe=25 mm,μ_e=30 mm and μe=35 mm)on stability bearing capacity of K6 single-layer reticulated shells(riseto-span ratio f/L=1/3,f/L=1/4,f/L=1/5,f/L=1/6 and f/L=1/7)is systematically studied.Furthermore,the failure mechanism of reticulated shell under random initial eccentric loads is investigated.The results obtained from200 numerical examples show that stability bearing capacity of reticulated shell with rise-to-span ratios 1/4~1/7 decrease almost linearly with the increase of initial eccentric load.The stability bearing capacity of reticulated shells with large rise-to-span ratio under full-span distributed load is less than that under asymmetric half-span distributed load when the initial load eccentricity is small,and the situation is just the opposite when the initial load eccentricity is large.The stability bearing capacity of reticulated shells with large rise-to-span ratio decreases significantly with the increase of initial load eccentricity.The proposed method of realizing initial load eccentricity and application procedures can be applied into other spatial lattice structures.

关 键 词：球面网壳 矢跨比 稳定承载力 荷载初偏心 随机缺陷 非线性 

分 类 号：TU311.2[建筑科学—结构工程] TU399