Shock-Sensitivity in Shell-Like Structures: With Simulations of Spherical Shell Buckling
Shock-Sensitivity in Shell-Like Structures: With Simulations of Spherical Shell Buckling
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DOI：
10.1142/s0218127416300032
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发表时间：
2016-02-01
影响因子：
2.2
通讯作者：
Sieber, Jan
中科院分区：
文献类型：
--
作者：
Thompson, J. Michael T.;Sieber, Jan
在压力增加的情况下，未屈曲的壳体处于亚稳态，随着接近屈曲载荷，该状态变得越来越不稳定。因此，为了引起过早屈曲，横向扰动必须克服逐渐减小的能量势垒，该能量势垒在屈曲时达到零。表现出这种行为的严重形式的两个典型问题是轴向压缩圆柱壳和外部加压球壳。针对圆柱体，最近提出了一种无损技术，使用横向探头测量非线性负载偏转特性来估计实验室样本的“冲击敏感性”。如果在路径上遇到对称性破坏的分叉，计算机模拟将显示如何通过受控的辅助探针来抑制这种情况。在这里，我们通过一般性评估单个控件如何捕获远程鞍点解来扩展我们的理解：特别是对称探针如何定位非对称解。然后，更具体地说，我们用点探针和环探针分析球壳，在具有挑战性的条件下测试该程序，以评估其适用范围。球壳不是分叉，而是在探头的严格控制下提供不稳定折叠（极限点）的挑战。
Under increasing compression, an unbuckled shell is in a metastable state which becomes increasingly precarious as the buckling load is approached. So to induce premature buckling, a lateral disturbance will have to overcome a decreasing energy barrier which reaches zero at buckling. Two archetypal problems that exhibit a severe form of this behavior are the axially-compressed cylindrical shell and the externally pressurized spherical shell. Focusing on the cylinder, a nondestructive technique was recently proposed to estimate the "shock-sensitivity" of a laboratory specimen using a lateral probe to measure the nonlinear load-deflection characteristic. If a symmetry-breaking bifurcation is encountered on the path, computer simulations showed how this can be suppressed by a controlled secondary probe. Here, we extend our understanding by assessing in general terms how a single control can capture remote saddle solutions: in particular, how a symmetric probe could locate an asymmetric solution. Then, more specifically, we analyze the spherical shell with point and ring probes, to test the procedure under challenging conditions to assess its range of applicability. Rather than a bifurcation, the spherical shell offers the challenge of a destabilizing fold (limit point) under the rigid control of the probe.