考虑弯扭形变的薄壁箱形梁的非线性后屈曲

Nonlinear post-buckling of thin-walled box beams considering bending and torsion

在大位移和扭转的前提下,通过一中等弯曲扭转的位移场描述了薄壁箱形梁在偏心载荷作用下的静稳定性问题。该非线性公式可用于分析简支薄壁箱形梁在不同载荷作用下的屈曲和后屈曲行为。采用伽辽金方法将非线性微分系统离散,并通过牛顿-拉普森增量迭代法求解得代数方程组。数值计算结果表明,当前屈曲位移不可忽略时,经典的横向屈曲预测是保守的,而非线性屈曲的分析解更为可靠。其中考虑了载荷高度参数对非线性屈曲性能的影响,并将计算的屈曲响应结果与采用壳单元的有限元结果(ANSYS)进行了比较。

In this paper, the static stability of thin-walled box beams under eccentric loads is described by using a displacement field with medium bending-torsion under the premise of large displacement and small torsion.The nonlinear formula is applied to the pre-buckling and post-buckling behavior of simply supported box beams under different loads.Galerkin method is used to discretise the nonlinear differential system.The incremental Newton-Raphson method is used to solve the algebraic equation.The numerical results show that when the current buckling displacement is not negligible, the classical lateral buckling prediction is conservative and the nonlinear buckling solution is more reliable.In this paper, the effect of load height parameters on the analysis results is considered, and the calculated post-buckling response is compared with the finite element result(ANSYS) using shell elements.