基于双向渐进结构优化法的钢桥系统失效模式识别

发布时间：2018-06-24 13:40

本文选题：桥梁工程 + 钢桥　；参考：《中国公路学报》2017年03期

【摘要】：准确模拟钢桥系统失效状态,实现结构失效状态的转移是钢桥结构系统主要失效模式识别算法的核心之一。针对钢桥中已屈服的失效杆件在继续强化或卸载情况下可能导致的结构内力重分布现象,以及通过删除失效单元并对失效单元所在节点外施加虚载实现结构拓扑状态转变的简化方法难以精确模拟结构实际受力性能的问题,提出了更全面反映钢材在弹性、屈服、强化、强化后卸载这4个阶段力学性能的受拉弹-塑性材料本构模型,钢材受压时采用考虑屈服应力折减的弹-塑性本构模型,并引入双向渐进结构优化法实现结构分析状态的自动转移;通过应力判断准则确定拉压杆件的弹塑性状态以及是否出现局部卸载现象,在钢桥系统失效模式搜寻过程中完成材料本构模型随单元受力状态的自动转换,直至达到材料极限强度后才予以删除这些杆件。结果表明:该方法充分考虑了钢桥构件间的相互影响关系与结构的内力重分布现象,通过精细化分析与结构状态自动转移,实现钢桥结构系统失效路径的搜寻;结合阶段临界强度分枝-约界法编制的识别钢桥主要失效模式的计算程序,实现了钢桥系统失效树主干和主枝的快速识别和生成,并成功识别出算例钢桁架桥的主要失效模式以及伪失效模式。
[Abstract]:Accurately simulating the failure state of steel bridge system and realizing the transfer of structure failure state is one of the core algorithms for identifying the main failure modes of steel bridge structure system. In view of the phenomenon of internal force redistribution caused by the failure member of steel bridge under the condition of continuous strengthening or unloading, And the simplified method of removing the failure element and applying virtual load outside the node to realize the structural topology state transformation is difficult to accurately simulate the actual mechanical behavior of the structure. A more comprehensive reflection of the elasticity and yield of steel is put forward. The tensile elastic-plastic material constitutive model of the four stages of mechanical properties after strengthening and strengthening is used. The elastic-plastic constitutive model considering the reduction of yield stress is adopted when the steel is under compression. The bidirectional progressive structural optimization method is introduced to realize the automatic transfer of the structural analysis state, and the elastic-plastic state and the local unloading phenomenon are determined by the stress judgment criterion. In the process of searching failure mode of steel bridge system, the material constitutive model is automatically transformed with the stress state of the element, and these members are deleted until the ultimate strength of the material is reached. The results show that the method fully considers the interaction between the steel bridge members and the redistribution of internal force of the structure, and realizes the search of the failure path of the steel bridge structure system through fine analysis and automatic transfer of the structure state. Combined with the calculation program of identifying the main failure modes of steel bridges compiled by the method of critical strength bifurcation and reduction, the fast identification and generation of the main branches and branches of the steel bridge system are realized. The main failure modes and pseudo-failure modes of steel truss bridges are successfully identified.
【作者单位】：长安大学公路学院;长安大学公路大型结构安全教育部工程研究中心;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057706) 国家自然科学基金项目(211021140372) 中央高校基本科研业务费专项资金项目(10821153501,310821153401,310821161021,310821151020)
【分类号】：U448.36

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