采用不同的动力学模型对比研究扁平加劲薄壳结构的临界状态

目前大多采用Kantorovich逼近算法研究棱柱形平板和加劲薄壳结构的屈曲应力,该方法参考了Von Karman和Koiter-Sanders理论,当预测的屈曲模态涉及平面内和平面外位移的比较时,后者引入了Green-Lagrange应变张量的概念。此外,为了突出Koiter-Sanders模型的非线性特性,进一步考虑了两个中间模型,根据不同的理论方法选择了改进的Von Karman模型和伪似然模型,以简化数值计算。结果表明,至少从实用的角度看来,在所选择的3个模型的计算结果基本相同的条件下,在不能忽视平面内位移的屈曲问题中,Von Karman模型过高地估计了临界荷载。

Critical Behavior of Flat and Stiffened Shell Structures Through Different Kinematical Models: A Comparative Investigation

In the present work buckling stresses of prismatic flat and stiffened shell structures are derived within the framework of the Kantorovich approach, making reference to both Von Karman and Koiter-Sanders theories, the latter exploiting the Green-Lagrange strain tensor which is needed if the expected buckling modes involve comparable in-plane and out-of-plane displacements. Additionally, in order to highlight the contribution of each nonlinear term of the Koiter-Sanders model, two further intermediate choices are also considered, namely an enhanced Von Karman model and a spurious model which collects selected terms from different theoretical approaches, generally adopted in literature with the aim of simplifying the numerical analyses. The obtained results show how in buckling problems where the weight of in-plane displacements cannot be neglected the Von Karman model tends to overestimate the critical load, while the three considered alternative models result substantially equivalent, at least from the practical standpoint.