Research on influence of initial curvature of members on elasto-plastic stability of reticulated shells
Research on influence of initial curvature of members on elasto-plastic stability of reticulated shells
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发表时间：
2012
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通讯作者：
Jiachuan Yan;Fan Feng;Z. Cao
中科院分区：
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作者：
Jiachuan Yan;Fan Feng;Z. Cao
为研究杆件初曲率对单层网壳结构弹塑性稳定性的影响，采用多梁法模拟杆件初曲率，基于ANSYS有限元软件，提出了两种杆件初曲率的引入方法。根据构件初曲率的随机性，提出了随机缺陷模态法。以Kiewitt-8型网壳为例，阐述了随机缺陷模态法的模拟过程，并研究了杆件初曲率方向角和幅值随机变量对网壳结构稳定性的影响。根据随机缺陷模态法的计算结果，建立了修正的一致缺陷模态法。基于该方法，对Kiewitt-6、Kiewitt-8和短程线单层网壳结构进行了考虑杆件初曲率影响的稳定性分析。对于节点无偏差和有偏差的结构，定量地得到了构件初曲率对结构承载力的影响。结果表明，对于节点无偏差和节点有偏差的结构，构件的初曲率会明显降低结构的承载力，改变结构的塑性发展程度。杆件初曲率对单层网壳结构弹塑性稳定性的影响不可忽略，修正的一致缺陷模态法可以有效地估计考虑杆件初曲率影响的网壳结构的下限承载力。
To investigate the influence of initial curvature of members on the elasto-plastic stability of single-layer reticulated shell structures, the multi-beam method was adopted to model the initial curvature of members, and based on the FEA package ANSYS, two methods were proposed to introduce the initial curvature of members of reticulated shells. According to the randomness of initial curvature of members, the random imperfection mode method was presented. Taking a Kiewitt-8 dome as an example explained the simulation process of the random imperfection mode method, and investigate the influence of direction angle and amplitude random variables of initial curvature of members on the stability of the reticulated shell structure. From the result of the random imperfection mode method, the modified consistent imperfection mode method was established. Then, based on this method, the stability of the Kiewitt-6, Kiewitt-8 and geodesic single-layer reticulated shells considering the influence of initial curvature of members were analyzed. For the structure without and with nodes deviation, the influences of initial curvature of members on the bearing capacity of the structures were obtained quantitatively. The results show that, for the structure without and with nodes deviation, the initial curvature of members can decrease the bearing capacity of the structure obviously, and change the degree of plasticity development of the structure. The influence of initial curvature of members on the elasto-plastic stability of single-layer reticulated shells cannot be neglected, and the modified consistent imperfection mode method is effective to estimate the lower bearing capacity of the reticulated shell structures considering the influence of initial curvature of members.