局部火灾下钢框架结构整体性能的非线性分析

本文用有限元法对局部火灾下钢框架结构的整体性能进行了分析，分析中考虑了包含温度变形影响的几何非线性、随温度升高材料性能的不断变化以及杆件截面温度分布不均匀等因素的影响。基于虚功原理，文章导出了温度荷载矩阵、温度几何刚度矩阵等概念，并编制了用于计算任意温度状态下结构的极限承载力或任意荷载状态下结构的温度极限值的有限元程序。同国外试验结果的比较验证了本文分析的正确性。

Nonlinear Analysis of the Overall Behavior of Steel Frames under Localized Fire Conditions

In this paper, the overall behavior of steel frames under localized fire conditions has been ana-lyzed by the finite element method. The effects of geometric nonlinearity including temperature deformatiofy the temperature - dependent variation of nonlinear material property and the nonuniform temperature distribution in each member are considered in the analysis. Based on the principle of virtual work, the temperature load vector and the temperature geometric stiffness matrix are derived. A finite e1ement program for calculating either the ultimate load of structure under a specified temperature or the critical temperature of a structure under any load level is also developed. The accuracy of the method has been verified by comparison with test results available abroad.