Spatial chaos as a governing factor for imperfection sensitivity in shell buckling
Spatial chaos as a governing factor for imperfection sensitivity in shell buckling
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DOI：
10.1103/physreve.100.032205
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发表时间：
2019-09-06
影响因子：
2.4
通讯作者：
Pirrera, Alberto
中科院分区：
文献类型：
--
作者：
Groh, Rainer M. J.;Pirrera, Alberto
壳体屈曲对初始缺陷极为敏感。一般认为，这种敏感性是由亚临界（不稳定）屈曲引起的，即初始几何缺陷迅速侵蚀理想壳体的理想屈曲载荷。然而，人们很少意识到，亚临界状态也会产生强烈的空间局部屈曲模式倾向。局部化的空间多样性意味着一个大的可能的轨迹不稳定，也被称为空间混沌，每个轨迹仿射到一个特定的缺陷。使用一个玩具模型，即软化弹性基础上的链接系统，我们表明，空间混沌导致一个大的传播屈曲载荷，即使是看似不可区分的随机缺陷等幅值。通过施加一个主要的缺陷，强敏感性的随机缺陷得到改善。通过主要缺陷或弹性剪裁控制平衡轨迹屈曲的能力为设计对屈曲不敏感的壳体创造了有趣的可能性。
Shell buckling is known for its extreme sensitivity to initial imperfections. It is generally understood that this sensitivity is caused by subcritical (unstable) buckling, whereby initial geometric imperfections rapidly erode the idealized buckling load of the perfect shell. However, it is less appreciated that subcriticality also creates a strong proclivity for spatially localized buckling modes. The spatial multiplicity of localizations implies a large set of possible trajectories to instability-also known as spatial chaos-with each trajectory affine to a particular imperfection. Using a toy model, namely a link system on a softening elastic foundation, we show that spatial chaos leads to a large spread in buckling loads even for seemingly indistinguishable random imperfections of equal amplitude. By imposing a dominant imperfection, the strong sensitivity to random imperfections is ameliorated. The ability to control the equilibrium trajectory to buckling via dominant imperfections or elastic tailoring creates interesting possibilities for designing imperfection-insensitive shells.