钢结构直接分析法在设计软件中的应用

Application of direct analysis method of steel structure in design software

钢结构设计中的直接分析法在结构力学模型中引入整体和杆件初始缺陷,在分析过程中考虑P-△和P-δ效应,并以求取的内力作为校核构件的依据,该方法具有概念清晰等优点。对比了常用设计软件的直接分析法应用方式,并基于SAP2000软件提供的OAPI接口,开发了可快速施加杆件初始缺陷的插件,并通过多个案例探讨了直接分析法的应用要点。通过对超静定结构进行弹塑性全过程分析,得到了结构的承载力设计值与承载力极限值,获得了结构系统杆件失稳→塑性开展→卸载的全过程响应。同时分别采用传统的一阶弹性分析法与直接分析法,求取结构达到承载力设计值时杆件内力分布,对比了两种方法求得内力的差异,并分析了产生差异的原因。所采用的编译方法和技术途径可为直接分析法在SAP2000等有限元软件中的应用提供参考。

In the direct analysis method of steel structure design,integral and initial defects of members were introduced into the structural mechanics model.The P-△ and P-δ effects were taken into account in the analysis process.The internal forces were obtained as the basis for checking components,this method had the advantages of clear concepts.The application of direct analysis method in common design software was compared.Based on the OAPI interface provided by SAP2000 software,a plug-in that could quickly apply the initial defects of members was developed.The application points of direct analysis method were discussed through several cases.Through the elastic-plastic whole process analysis of statically indeterminate structures,the design value and ultimate value of bearing capacity of structures were obtained, and the whole process response of structural system member instability→plastic development→unloading was ob,tained.At the same time,the traditional first-order elastic analysis method and direct analysis method were used to calculate the internal force distribution of members when the structure reached the design value of bearing capacity.The differences between the two methods were compared and the reasons for the differences were analyzed.The compiling method and technical approach adopted could provide reference for the application of direct analysis method in finite element software such as SAP2000.