杆件去除与内力变更时空间网架结构的简捷计算法

A Simplified Method for Analysis of Space Grid Structures due to the Removal of Members or Modification of Members' Internal Force

本文采用矩阵位移法,引入初内力的概念,提出并建立了初内力准则方程式,再运用线性叠加原理来简化分析计算杆件去除与内力变更时的空间网架结构。这种简捷计算法在所讨论的工况下只要一次性的建立、分解和应用网架结构的总刚度矩阵,无须重复多次建立和分解总刚度矩阵,从而使计算工作量成倍地甚至几十倍地大幅度减少。特别是当网架结构多根杆件同时断杆、依次先后断杆、预应力及分期分批施加预应力时,采用本文方法可更方便地求得各工况全过程的网架内力、变位及其变化规律。文中附有多个算例,计算结果表明本文提出的简捷计算法是正确、可靠和有效的。

Based on the matrix displacement method and the principle of linear superposition, the conception of initial internal force is put forward and the standard equations of initial internal force are established in this paper, which can be used for analysis of space grid structures due to the removal of members or modification of members' internal force. With this simplified method, the global stiffness matrix of structure is set up and decomposed only by one time under discussed load conditions and the computation rate is greatly improved. The internal force, displacement and their change regularity of space structures can be calculated conveniently, especially when the load conditions happen such as multi members are cut off at same time or one after another, and members are pre - stressed in turns. The results of numerical examples show that the proposed simplified mehtod is correct, reliable and effective.