基于二阶梁柱单元的精细塑性铰算法

A Refined Plastic Hinge Method Based on Second-Order Beam-Column Elements

采用精细塑性铰法考虑残余应力和逐步塑性,并引入弓形效应来提高计算精度,同时基于截面组合法建立的工字形或H形截面的屈服面方程进行严格推导,提出一种单元恢复力迭代算法,减少了半理论半经验公式的使用。此外,所采用的梁柱单元还可以考虑梁构件剪切变形和几何初始缺陷的影响。相比之前的方法,该方法能在进行塑性铰分析的同时,在单元的轴力表达式中考虑二阶效应,更全面地考虑非线性因素影响。最后,通过两个经典算例的对比,证明了该方法具有高效率和高精度的特点。

This paper adopts the refined plastic hinge method with considering residual stress and gradual plasticization,and the bowing effect is also introduced to improve the computational accuracy.The proposed iterative force recovery method is strictly derived by the yield function of an I or H section based on the section assemblage concept,which reduces the application of empirical formulas.Besides,the adopted second-order beam-column element allows the shear deformation and the initial geometric imperfection of members.Compared with previous methods in the literatures,the proposed method can consider the second-order effect in the expression of axial force of element when performing the plastic hinge analysis.Therefore,the nonlinear factors can be considered more comprehensively.Finally,two classical examples are given to demonstrate the accuracy and efficiency of the proposed method.