The main popular theoretical method adopted to study end - plate connection is finite element technique under monotonic loading at present . this paper applies nonlinear ( material , geometry and contact ) finite element method to analyze the behaviors of connections under cyclic load at fist time . contact elements are set between end plate and column flange , screw cap and neighborhood plane , bolt bar and hole 对于端板连接的理论分析，目前国内外的研究主要局限在单向加载有限元分析范畴，本文首次采用三维非线性(包括材料、几何与状态非线性)有限元对端板连接进行了循环加载分析，端板与柱翼缘间、螺栓头(帽)与相邻板件间、螺栓杆与孔壁间都设置了反映边界状态的接触单元。
( 3 ) by using an elastic - plastic material model , the nonlinear analysis is taken on the rectangular tube and simply supporte d plate , and the ultimate carrying load capacity pu is obtained . the results show that the buckling mode is in accordance with the assumption of elastic analysis , and so shows the ultimate mode ( 3 )采用弹塑性模型，考虑几何非线性理论，利用ansys软件对矩形钢管考虑板组相关屈曲影响和不考虑相关屈曲影响(将矩形管板件按四边简支板对待)两种情况进行了屈曲后分析，分别得出其极限承载力p _ u ，并分析了矩形管的屈曲过程。
