空间杆系结构的弹塑性大位移分析  

ELASTO-PLASTIC LARGE DISPLACEMENT ANALYSIS OF SPATIAL SKELETAL STRUCTURES

作　　者：叶康生[1] 吴可伟[1] 

机构地区：[1]清华大学土木工程系,清华大学土木工程安全与耐久教育部实验室,北京100084

出　　处：《工程力学》2013年第11期1-8,共8页Engineering Mechanics

基　　金：国家自然科学基金项目(51078199);长江学者和创新团队发展计划项目(IRT00736)

摘　　要：为适当降低杆系结构弹塑性分析的计算量,该文假设单元塑性变形集中于单元端部。在单元端部截面上,将截面分割为若干小块面积,用小块面积中心处材料的弹塑性性能代替整个小块面积的弹塑性性能。通过对小块面积弹塑性性能的分析,得出端部截面的弹塑性刚度,再将其与单元内部弹性部分的截面刚度沿杆长进行Gauss-Lobatto积分,由此获得梁单元的弹塑性刚度矩阵。该文对小面积中心点采用基于材料应变等向强化的弹塑性本构关系,为准确分析杆端截面小块面积的弹塑性应力状态,该文提出了有效的应力调整算法以修正计算过程中偏离屈服面的应力值。数值算例表明,该文方法准确、高效、可靠。In order to reduce the computational amount of the elasto-plastic analysis on skeletal structures appropriately, the plastic deformation is assumed being concentrated on both ends of an beam element. The end cross-sections of the beam element are discretized into several small areas. The elasto-plastic behavior of each small area is represented by the elasto-plasticity on its center which is analyzed to form the elasto-plastic stiffness of the end cross-section. The element＇s elasto-plastic tangent stiffness is obtained from the integration of cross-section stiffness along the element by using Gauss-Lobatto quadrature scheme. The incremental constitutive relationship between the small areas is set up, which includes the isotropic hardening of material, and an effective algorithm is presented to correct the stresses which drift from the yield surface during material nonlinear analysis. Numerical examples show that this method is accurate, efficient and reliable.

关 键 词：空间杆系结构 弧长法 大位移 弹塑性 稳定 

分 类 号：TU318[建筑科学—结构工程]