中文摘要：

一根合成盒子横梁滑倒可以减少它的僵硬，扩大它的变丑并且影响它的表演。在这个工作，管理微分方程和合成盒子横梁的边界条件被建立。联合微分方程的分析答案也被建立。自由的部分度被采用建立三维的横梁的一个新 FEA 元素，考虑 slip 效果。滑倒并且它的一阶的衍生物被介绍进概括了自由的度的合成盒子横梁的节点。横梁元素的僵硬矩阵和负担数组被建立。一个三维的非线性的计算节目被得出。结果证明元素可靠、容易划分并且对大跨度的合成盒子横梁的特殊非线性的分析合适。

英文摘要：

Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.