空间钢框架结构的改进双重非线性分析

为了探讨三维结构的高等分析方法,给出基于UL法的严格三维单元虚功增量方程,详细推导了考虑剪切变形影响的三维梁柱单元的几何非线性切线刚度矩阵和基于三维单元简化塑性区模型的双重非线性刚度方程,并编制空间钢框架结构的双重非线性分析程序。使用包括几何与材料双重非线性的数值算例来验证方法和计算机程序的可行性、精确度与有效性。利用该程序,只需一个单元/构件即可准确预测空间钢框架结构的极限承载力与失稳模态,提高了结构的非线性分析效率。

MODIFIED DUAL NONLINEAR ANALYSIS OF SPACE STEEL FRAME STRUCTURES

To explore the advanced analysis approach of three-dimensional structures, an incremental virtual work equation for the stringent three-dimensional element is proposed based on the UL method. The stringent geometric nonlinear tangent stiffness matrix for three-dimensional beam-column element is derived in detail using interpolation functions cosidering shear effects. The dual nonlinear incremental stiffness equation is deduced besed on the proposed simplified plastic zone model for three-dimensional beam-column element. A dual nonlinear analysis computer program for space steel frame structures is developed. Numerical examples including both geometric and material nonlinearites are used to demonstrate the robustness, accuracy and efficiency of the proposed analytical method and the computer program. The developed computer program can be used to predict accurately the utmost resistance capability and instability mode of three-dimensional columns and space frames by modelling each physical member as one element in most cases.