汤宏伟, 钟宏志. 考虑杆件初弯曲的网壳弹塑性稳定性的弱形式求积元分析[J]. 工程力学, 2019, 36(1): 165-174. DOI: 10.6052/j.issn.1000-4750.2017.11.0842
引用本文: 汤宏伟, 钟宏志. 考虑杆件初弯曲的网壳弹塑性稳定性的弱形式求积元分析[J]. 工程力学, 2019, 36(1): 165-174. DOI: 10.6052/j.issn.1000-4750.2017.11.0842
TANG Hong-wei, ZHONG Hong-zhi. ELASTO-PLASTIC STABILITY ANALYSIS OF LATTICED SHEELS WITH INITIALLY CURVED MEMBERS BY WEAK-FORM QUADRATURE ELEMENTS[J]. Engineering Mechanics, 2019, 36(1): 165-174. DOI: 10.6052/j.issn.1000-4750.2017.11.0842
Citation: TANG Hong-wei, ZHONG Hong-zhi. ELASTO-PLASTIC STABILITY ANALYSIS OF LATTICED SHEELS WITH INITIALLY CURVED MEMBERS BY WEAK-FORM QUADRATURE ELEMENTS[J]. Engineering Mechanics, 2019, 36(1): 165-174. DOI: 10.6052/j.issn.1000-4750.2017.11.0842

考虑杆件初弯曲的网壳弹塑性稳定性的弱形式求积元分析

ELASTO-PLASTIC STABILITY ANALYSIS OF LATTICED SHEELS WITH INITIALLY CURVED MEMBERS BY WEAK-FORM QUADRATURE ELEMENTS

  • 摘要: 初始缺陷是影响网壳稳定性的主要因素之一。技术规程建议的一致缺陷模态法综合考虑了结点的位置偏差与杆件的初弯曲,但现有计算方法难于便捷地单独全面体现初弯曲的影响。该文基于几何精确梁理论构造了一种弱形式求积元模型。通过引入纤维模型模拟材料非线性,结合柱面弧长法实现了对空间曲梁结构的弹塑性大位移分析,通过算例验证了提出模型的有效性。该模型构建不需具体指定位移形函数,避免了使用有限元软件中的复杂建模过程。运用该模型计算了几类典型网壳在杆件初弯曲方向随机分布,不同弯曲挠度下的极限承载力。计算结果表明,在现有钢结构生产工艺下杆件初弯曲的缺陷对于网壳稳定性的影响较小,不起控制作用。通过与一致缺陷模态法的计算结果和空间网格结构技术规程计算的承载力进行对比,对规范的承载力计算公式提出了考虑特殊网壳形式及材料屈服强度的改进建议。

     

    Abstract: Initial imperfection is one of the major influential factors for the stability of a latticed shell. The consistent imperfection mode method recommended by current technical specifications consider both nodal deviation and initial curvature of members, but the sole influence of initial curvature cannot be easily identified. In this study, a weak form quadrature beam element model was formulated based on the geometrically exact beam theory. Incorporating the fiber model for material nonlinearity and the arc length algorithm, elasto-plastic large displacement analysis of spatial curved beam structures was conducted. Examples were examined to verify the effectiveness of the proposed model. By the use of the proposed model, displacement shape functions are not necessarily designated and delicate modeling of curved beams in other finite element software can be avoided. In the analysis, ultimate loads of several typical latticed shells consisting of members with random initial curvature were obtained. It is found that the member defect of initial curvature had little effect on the load-carrying capacity of a latticed shell and therefore was not the main factor for stability under the circumstances of current steel-production quality control technique. Results were compared with those from the consistent imperfection mode approach and the technical specification for space frame structures. It is suggested that the yield strength of material and the specific form of a latticed shell should be considered in the formula of the technical codes and standards.

     

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