采用夹层模型对压杆蠕变屈曲问题的分析

Using the Sandwich Model to Analyze the Creep Buckling of Compressed Columns

基于夹层模型理论,建立了具初始缺陷两端可动铰支压杆的非线性蠕变屈曲控制方程.由于对压杆截面的简化处理,所得控制方程仅含时间函数,极易求得问题的近似解析解或数值解.为验证该方法的正确性和计算精度,基于一般压杆蠕变屈曲理论,对相应问题进行半解析法求解.结果表明,两种解法所确定的屈曲临界时间十分接近,说明当材料非线性较小时,采用本文所提出的简化模型和分析方法,可方便和精确地对压杆蠕变屈曲问题进行定量分析.

By means of the sandwich model, this paper established the nonlinear equations of the creep buckling for a compressed column with two-end movable hinge and initial imperfection. These equations involved only time function and could be easily solved approximately and numerically by simplifying the section of the compressed column. Then, based on the creep buckling theory of the general compressed column, the problem was analyzed with the semi-analytical method in order to validate the correctness and computation precision of the method. The results showed that the critical buckling time determined by these two methods were very close. When the material nonlinearity was small, the creep buckling of the compressed column could be analyzed conveniently and precisely by adopting this simplified model and analytical method.