郑义凡, 曾滨, 周臻, 许庆. 基于非线性屈曲材料模型的张弦桁架连续倒塌分析[J]. 工程力学, 2022, 39(10): 152-160. DOI: 10.6052/j.issn.1000-4750.2021.06.0437
引用本文: 郑义凡, 曾滨, 周臻, 许庆. 基于非线性屈曲材料模型的张弦桁架连续倒塌分析[J]. 工程力学, 2022, 39(10): 152-160. DOI: 10.6052/j.issn.1000-4750.2021.06.0437
ZHENG Yi-fan, ZENG Bin, ZHOU Zhen, XU Qing. ANALYSIS ON PROGRESSIVE COLLAPSE OF CABLE-STAYED ARCH-TRUSS BASED ON NONLINEAR BUCKLING MATERIAL MODEL[J]. Engineering Mechanics, 2022, 39(10): 152-160. DOI: 10.6052/j.issn.1000-4750.2021.06.0437
Citation: ZHENG Yi-fan, ZENG Bin, ZHOU Zhen, XU Qing. ANALYSIS ON PROGRESSIVE COLLAPSE OF CABLE-STAYED ARCH-TRUSS BASED ON NONLINEAR BUCKLING MATERIAL MODEL[J]. Engineering Mechanics, 2022, 39(10): 152-160. DOI: 10.6052/j.issn.1000-4750.2021.06.0437

基于非线性屈曲材料模型的张弦桁架连续倒塌分析

ANALYSIS ON PROGRESSIVE COLLAPSE OF CABLE-STAYED ARCH-TRUSS BASED ON NONLINEAR BUCKLING MATERIAL MODEL

  • 摘要: 在拉索失效等工况下,张弦桁架连续倒塌时主要破坏形式为压杆的受压屈曲和拉杆的受拉屈服。为考虑受压杆件的屈曲效应,目前分析研究一般采用将每根杆件划分为多个单元并施加初始几何缺陷的方法,分析效率低、耗时长。针对这一问题,在梁柱单元修正混合强化本构模型的基础上,结合梁柱单元非线性屈曲材料模型,提出了张弦桁架连续倒塌快速分析方法,并通过算例验证了材料模型的正确性。利用ANSYS/LS-DYNA编制了所提出材料模型的子程序,基于增量动力分析法,开展了张弦桁架在拉索失效工况下的连续倒塌分析。在此基础上,对三种加强方式的结构进行增量动力分析,研究了加强部分重要杆件对张弦桁架在拉索失效工况下抗连续倒塌能力的影响。开展了张弦桁架连续倒塌易损性研究,综合评估了张弦桁架抗连续倒塌能力。结果表明:快速分析方法比传统分析方法缩短计算耗时39.89%;在加强了部分跨中上弦杆、跨中下弦杆后,张弦桁架的极限承载力最多提高16.67%,达到两种形态所对应的荷载值也均有所提高;基于快速分析方法可有效评估张弦桁架的综合抗连续倒塌能力。

     

    Abstract: Under the conditions such as cable failure, the failure modes of progressive collapse of cable-stayed arch-trusses are the buckling of compression members and tension yielding of tension members. To consider the buckling effect of compressed members, the current analysis generally adopts the method of dividing each member into multiple elements and applying initial geometric defects, which is inefficient and time-consuming. To solve this problem, based on the modified mixed hardening constitutive model of beam-column elements, combined with the nonlinear buckling material model of beam-column elements, a rapid analysis method for progressive collapse of cable-stayed arch-trusseses is proposed, and the correctness of the material model is verified by a calculation example. Using ANSYS/LS-DYNA to compile the subroutine of the proposed material model, based on the incremental dynamic analysis method, the progressive collapse analysis of a cable-stayed arch-truss under the cable failure condition is executed. On this basis, the incremental dynamic analysis of three kinds of reinforced structures is carried out, and the influence of reinforcing critical members on the resistance of progressive collapse under cable failure conditions is investigated. A study on progressive collapse fragility of cable-stayed arch-trusses is executed, and the resistance of progressive collapse is comprehensively evaluated. The results show that: the rapid analysis method shortens the calculation time by 39.89% compared with the traditional analysis method; after strengthening some mid-span upper chord and mid- span lower chord, the ultimate bearing capacity is increased by 16.67% at most, and the load values corresponding to the two forms are also improved. Based on the rapid analysis method, the resistance of progressive collapse of cable-stayed arch-trusses can be effectively evaluated.

     

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