单轴对称截面压杆考虑剪力滞效应的临界荷载

以单轴对称工字截面压杆为对象,针对截面几何尺寸不同的上、下翼缘分别设定相应的剪滞翘曲函数,利用能量变分原理并结合微分方程组降阶法,推导了单轴对称截面压杆考虑剪力滞效应的临界荷载的闭合解,由此考察了欧拉临界荷载公式的可靠性和适用条件.结果表明,欧拉公式高估了薄壁压杆的临界荷载;翼缘惯性矩与全截面惯性矩之比和跨宽比对临界荷载有一定影响,其中后者的影响更明显;欧拉临界荷载公式只适用于跨宽比较大的压杆.

Critical load for compressive bar with monosymmetric section considering the shear lag effect

The compressive bar with monosymmetric section was taken for an example,the corresponding shear lag warping functions were set respectively to top and bottom flange which have different section geometry sizes,closing solution,that critical load for compressive bar with monosymmetric section considering the shear lag effect was gotten,by means of energy variational principle and the reduced order method of differential equations.Thus the reliability and applicable conditions of Eular critical load formula was examined.The results show that Eular formula overestimates the critical load of thin-walled compressive bar;The ratio of the inertia of flange section and the whole section as well as the ratio of span and width have some influenecd on the critical load,but the influence of the latter is more obvious.Euler critical load formula is only applied to the compressive bar wit big ratio of span and width.