徐变效应的位移分析法

位移法分析超静定结构徐变效应的关键是求单元的徐变固端力.本文根据徐变分析的力法和虚功原理,推导出杆系结构一次加载的单元徐变固端力计算公式,发现单元的徐变固端力是杆件的徐变系数和弹性杆端力的函数。根据推导出的公式,用FORTRAN语言编制了结构徐变分析的位移法计算机程序,并对一个框架算例进行了徐变分析.结果表明,结构各部分的浇筑时间差和持荷时间对结构的受力和变形影响很大,在实际工程设计中不能忽略徐变对结构的影响.

Displacement Method of Creep Effect Analysis

The key problem of displacement method in the creep effect analysis of statically indeterminate structures is to determinate the fixed-end forces of the element.Based on the ideas of force method and virtual-work principle,the calculation formulas of the fixed-end forces in element-system structures were deduced.It was found that the fixed-end forces of element were the function of the creep coefficient and the elastic fixed-end forces of the element.According to the formulas,a computer program of the displacement method to analyze creep effect was made in FORTRAN language.The creep effect of a frame was analyzed by using this program.It was shown that the construction process and the sustaining time of the loads had great effects on structural mechanical performance.In practical engineering structures,creep effect cannot be neglected.