空间支撑钢框架结构的三重非线性分析

为了探讨三维结构的高等分析方法,本文将有限单元法与梁柱法相结合,建立了空间支撑钢框架结构的三重非线性分析方法,该法综合考虑了几何、材料和连接非线性效应。文中基于非线性连续介质力学理论和考虑剪切效应的稳定插值函数建立的严格三维梁柱单元刚度矩阵,包含了轴向、剪切、双向弯曲与扭转及其各耦合效应。三维单元简化塑性区模型可模拟塑性扩展,利用单元两端抗转弹簧和考虑支撑效应的节点域剪切变形模型来模拟连接非线性。使用包括几何、材料和连接非线性的数值算例来检验本文方法和所编计算机程序的可行性、有效性与精确度。算例表明,利用本文方法,每个构件只需一个单元即可准确预测三维结构的极限荷载与失稳模态,可提高结构非线性空间性能的分析效率。

A triple nonlinear analysis approach for braced space steel frame

For exploring the advanced analysis approach of three dimension structures, a triple nonlinear analysis approach for braced space steel frame is proposed based on the combination of finite element method and traditional beam column method, in which geometric, material and connection nonlinear effects are considered. The stiffness equation for stringent three dimension beam column element was derived using nonlinear continuum mechanics and stability interpolation function considering shear effects, and the coupling effects between axial, flexural and torsional displacements were considered in the equation. A simplified plastic zone model for three demension beam column element and a joint panel zone model of braced space steel frame considering brace effects were established. Numerical examples including triple geometric, material and connection nonlinearites were given to demonstrate the robustness, accuracy and efficiency of the proposed analytical method and computer program. The developed computer program can be used to predict accutrately the ultimate strength and instability modality of three dimension structures by one element per member in most cases.