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针对弹性基底上板的局部稳定问题,应用能量法推导了非均匀荷载作用下矩形加劲板的局部屈曲非线性特征方程,建立了考虑弹性基底接触和纵向加劲肋作用的屈曲板迦辽金表达式;基于牛顿迭代法,建立了局部屈曲的非线性特征方程的增量迭代格式与屈曲荷载特征值的附加迭代方程。分析结果表明:屈曲系数计算结果与有限元分析结果误差小于2%,并且避免了有限元模拟的接触分析过程,计算效率较高;当荷载梯度为1时,设置加劲肋的偏心构件的局部稳定性明显增强,临界屈曲系数增加到51.1,是普通板件的2.5倍;加劲板件的纵向鼓曲波的长宽比约为0.6,鼓曲波纵向排列相对密集,而普通板件每个鼓曲波的长宽比约为1.0;在不增加加劲肋材料用量的前提下,设置纵向加劲肋的最优位置为距离板件受压侧边缘的2/5板宽处,临界屈曲系数增加为78.9,是普通板件的4倍;加劲肋的设置可将矩形钢管混凝土壁板的宽厚比增加到172,将界限值提高2倍以上。可见,在矩形钢管混凝土管壁设置纵向加劲肋能够有效提高偏压作用下管壁的局部稳定性,改善矩形钢管混凝土的截面尺寸。
In order to solve the problem of local stability of elastic base plate, the local buckling nonlinear characteristic equation of rectangular stiffened plate subjected to nonuniform load was deduced by energy method. The Buckling plate Galerkin expression with elastic substrate contact and longitudinal stiffener was established. Based on the Newton iteration method, an additional iteration equation of incremental iteration scheme and buckling load eigenvalue of nonlinear buckling characteristic equation is established. The results show that the error between the calculation results of the buckling coefficient and the finite element analysis is less than 2%, and the contact analysis process of the finite element simulation is avoided and the calculation efficiency is high. When the load gradient is 1, the local stability of the eccentric component The critical buckling coefficient is increased to 51.1, which is 2.5 times that of the ordinary plate. The aspect ratio of the longitudinal buckled curve of the stiffened plate is about 0.6, and the longitudinal distribution of the drum curve is relatively dense. However, The aspect ratio of the Qu Bo is about 1.0. Without increasing the amount of the stiffener, the optimal position of the longitudinal stiffener is set to be 2/5 of the width of the pressure side edge of the plate, and the critical buckling coefficient increases to 78.9, which is 4 times that of the ordinary plate. The stiffener is set to increase the width-thickness ratio of the rectangular CFST wall to 172 and increase the threshold more than 2 times. It can be seen that the longitudinal stiffeners on the rectangular CFST pipe wall can effectively improve the local stability of the pipe wall under bias and improve the cross-sectional dimensions of the concrete.