基于极限分析的下限定理 ,利用伽辽金边界元方法对二维结构进行离散 ,建立了结构极限 (下限 )分析的计算格式。利用弹塑性增量算法中同一增量步上不同迭代步的应力差作为基矢量构造了自平衡应力场 ,然后通过复合形法直接求解该非线性规划问题 ,得到了二维结构极限载荷下限乘子。计算结果表明了本文采用的方法的有效性 Based on the lower bound theorem of limit analysis, the two-dimensional structure is discretized using the Galerkin Boundary Element Method, and the computational format of the structural limit (lower bound) analysis is established. The self-balance stress field is constructed by using the stress difference of different iteration steps on the same incremental step in the elasto-plastic incremental algorithm as the base vector. Then the complex programming method is used to solve the nonlinear programming problem directly. The lower bound of the limit load of two- child. The calculation results show the effectiveness of the proposed method