匀速轴向压力作用下两边简支直杆的动力屈曲

Dynamic buckling of simply supported rod under uniform axial pressure

根据在不同的变形状态下匀速轴向受压的、两边简支的弹性直杆的动力屈曲控制方程,对直杆一阶、二阶形式的动力屈曲利用差分方法和有限元数值模拟方法进行计算和比较,并通过改变加载速度得到相应的数值解。计算结果表明:在保证精度的情况下,加载速度的增加使得两边简支直杆屈曲模态由一阶向二阶发生渐变;在屈曲刚发生阶段,屈曲载荷保持不变,之后屈曲载荷随着加载速度的增加而逐渐增大,且存在临界加载速度使屈曲载荷在该位置发生突变。

According to the governing equation of dynamic buckling of the elastic straight bar which is simply supported subjected to a uniform axial compression under different deformation conditions,the dynamic buckling of first and second order of a straight bar is calculated and compared by means of difference method and finite element numerical simulation.Also,the corresponding numerical solution is obtained by changing the loading speed.It is shown that the increase of the loading speed makes the buckling mode of the straight rod that is simply supported gradually change from one order to the second order when the precision is guaranteed.The buckling load remains the same in the beginning.After that,the buckling load is gradually increased with the increase of the loading speed.And also,there exists the critical loading speeds that make the mutation occurs.