随机杆件初弯曲对K6型网壳稳定承载力的影响研究
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摘要
单层网壳属于缺陷敏感型结构,初始缺陷对其稳定承载力影响较复杂。为研究随机杆件初弯曲对网壳整体承载力的影响,以K6型单层球面网壳为对象,推导了实现具有杆件随机初弯曲网壳的相关公式,并详细阐述了其在有限元程序中的实现方法,分别研究了杆件初弯曲幅值、弯曲方向角及二者耦合作用对网壳结构稳定承载力的影响程度。主要得出如下结论:当初弯曲幅值δ取为确定值l/1 000时,与理想网壳相比,承载力下降5%左右;当δ取为确定值l/250时,承载力下降14%左右。与随机初弯曲幅值相比,初弯曲方向角对网壳结构稳定承载力的影响较小。同时考虑弯曲幅值与弯曲方向角的随机性时,杆件初弯曲对网壳稳定承载力的影响更为显著。推导的建模公式及其有限元方法可推广至其它类型的空间网格结构中。
Single-layer reticulated shell is sensitive to imperfections,due to its complex effects on the stability of reticulated shell.To evaluate on the influence of random initial curvature of members on the load-carrying capacity of K6 reticulated shell,the related formulas establishing K6 reticulated shell with random initial curvature of members are widely developed,and the realization method of these formulas in finite element package is illustrated in details.The influences of initial curvature amplitude,angle and both of them on load-carrying capacity of K6 reticulated shell are investigated.The main conclusions are summarized as follows.Compared with perfect shell,limit load reduction of reticulated shell with amplitude δ=l/1 000 and δ=l/250 is about 5% and 14%,respectively.Amplitude of member curvature has larger effect on load-carrying capacity than angle of member curvature.The effect of initial curvature of member becomes more obvious when their randomness is taken into consideration.Developed related formulas and its realization method in finite element package can be extended into other space frame structures.
Single-layer reticulated shell is sensitive to imperfections,due to its complex effects on the stability of reticulated shell.To evaluate on the influence of random initial curvature of members on the load-carrying capacity of K6 reticulated shell,the related formulas establishing K6 reticulated shell with random initial curvature of members are widely developed,and the realization method of these formulas in finite element package is illustrated in details.The influences of initial curvature amplitude,angle and both of them on load-carrying capacity of K6 reticulated shell are investigated.The main conclusions are summarized as follows.Compared with perfect shell,limit load reduction of reticulated shell with amplitude δ=l/1 000 and δ=l/250 is about 5% and 14%,respectively.Amplitude of member curvature has larger effect on load-carrying capacity than angle of member curvature.The effect of initial curvature of member becomes more obvious when their randomness is taken into consideration.Developed related formulas and its realization method in finite element package can be extended into other space frame structures.
引文
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[3]FAN F,YAN J C,CAO Z G.Stability of reticulated shells considering member buckling[J].Journal of Constructional Steel Research,2012,77(10):32-42.DOI:10.1016/j.jcsr.2012.04.011.
[4]严佳川,范峰,曹正罡.杆件初弯曲对网壳结构弹塑性稳定性能影响研究[J].建筑结构学报,2012,33(12):63-71.DOI:10.14006/j.jzjgxb.2012.12.011.YAN Jiachuan,FAN Feng,CAO Zhenggang.Research on influence of initial curvature of members on elasto-plastic stability of reticulated shells[J].Journal of Building Structures,2012,33(12):63-71.DOI:10.14006/j.jzjgxb.2012.12.011D.(in Chinese)
[5]FAN F,YAN J C,CAO Z G.Elasto-plastic stability of singlelayer reticulated domes with initial curvature of members[J].Thin-Walled Structures,2012,60:239-246.DOI:10.1016/j.tws.2012.01.012.
[6]田伟,赵阳,董石麟.考虑杆件失稳的网壳结构稳定分析方法[J].工程力学,2012,29(10):149-156.TIAN Wei,ZHAO Yang,DONG Shilin.Stability analysis method for lattice shells accounting for member buckling[J].Engineering Mechanics,2012,29(10):149-156.(in Chinese)
[7]田伟,董石麟,干钢.网壳结构考虑杆件失稳过程的整体稳定分析[J].建筑结构学报,2014,35(6):115-122.DOI:10.14006/j.jzjgxb.2014.06.014.TIAN Wei,DONG Shilin,GAN Gang.Stability analysis method for lattice shells accounting for buckling of members[J].Journal of Building Structures,2014,35(6):115-122.DOI:10.14006/j.jzjgxb.2014.06.014.(in Chinese)
[8]丁阳,齐麟,杨律磊,等.考虑杆件失稳的初始缺陷单层网壳极限承载力分析[J].天津大学学报,2011,44(12):1070-1074.DING Yang,QI Lin,YANG Lülei,et al.Ultimate bearing capacity analysis of single layer latticed shell with initial imperfection considering member buckling[J].Journal of Tianjin University,2011,44(12):1070-1074.(in Chinese)
[9]丁阳,葛金刚,李忠献.考虑损伤累积及杆件失稳效应的网壳结构极限承载力分析[J].工程力学,2012,29(5):13-18,30.DING Yang,GE Jingang,LI Zhongxian.Analysis on ultimate bearing capacity of reticulated shell considering cumulative damage and instability of member[J].Engineering Mechanics,2012,29(5):13-18,30.(in Chinese)
[10]CHEN W F,ATSUTA T.Theory of beam-columns volume1:in-plane behavior and design[M].New York:McGrawHill,Inc.,1976.