摘要
单层球面网壳属于缺陷敏感型结构。为研究杆件偏心对单层网壳结构整体稳定承载力的影响,以K6单层球面网壳为研究对象,提出了能够考虑随机杆件偏心的力学简化模型,然后阐述了随机杆件偏心在数值计算中的实现方法,最后研究了不同大小偏心距对300个单层网壳稳定承载力的影响程度与规律,并探讨了网壳的失效机理与破坏过程。计算表明:K6型单层球面网壳的稳定承载力与偏心距的大小紧密相关。当偏心距较小时,如Δyi、Δzi、Δyj和Δzj的绝对值均值为1.064 mm时,与理想网壳相比,极限荷载下降幅度在5%以内,影响不显著;当偏心距较大时,如四者绝对值均值为2.660 mm时,极限荷载下降幅度超过了10%,影响非常显著。随着杆件偏心距的增大,网壳的稳定承载力近似线性地逐渐减小,稳定承载力的离散程度逐渐增大。随着偏心距的增加,极限荷载的概率分布类型由正态分布转变为非正态分布。提出的力学模型可推广至其他类型的空间网格结构中。
Single-layer reticulated shell is a structure sensitive to imperfection.To research on the influence of random member eccentricity on load-carrying capacity of K6 single-layer reticulated shell,a mechanical model of reticulated shell with member’s eccentricity to node is firstly developed,and realization methods and procedures of random member eccentricity in numerical analysis are clearly illustrated.Finally,the influence of different member eccentricities on load-carrying capacity of 300 reticulated shells are comprehensively researched,and the failure mechanism and destructive process are discussed.The numerical results are concluded as follows.The load-carrying capacity of K6 reticulated shell is affected more or less by the eccentricity magnitude of member.Compared with ideal shell,the ultimate load of reticulated shell will decrease within 5% when eccentricity is small.For example,Δyi,Δzi,Δyj and Δzj equal to the absolute mean value 1.064 mm.The ultimate load of reticulated shell will decrease significantly,for instance,the decline will exceed 10% when four parameters equal to the absolute mean value 2.660 mm.With the increment of eccentricity,load-carrying capacity will gradually decrease linearly,and dispersion degree of load-carrying capacity will generally increase.Probabilistic distribution of limit load changes to non-normal distribution from normal distribution with the increase of eccentricity.The developed mechanical model can be applied into other types of space frame structures.
作者
李会军
王超
肖姚
LI Huijun;WANG Chao;XIAO Yao(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China)
出处
《建筑钢结构进展》
CSCD
北大核心
2019年第6期72-79,共8页
Progress in Steel Building Structures
基金
国家自然科学基金(51408490)
国家留学基金(201706305044)
大学生创新创业训练计划项目(201710712046)
关键词
单层球面网壳
随机杆件偏心
离散程度
最大偏心距
稳定承载力
概率分布
single-layer reticulated shell
random member eccentricity
dispersion degree
maximum eccentricity
load-carrying capacity
probabilistic distribution
