Buckling analysis, design and optimisation of variable-stiffness sandwich panels
Buckling analysis, design and optimisation of variable-stiffness sandwich panels
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DOI：
10.1016/j.ijsolstr.2016.06.007
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发表时间：
2016-10-01
影响因子：
3.6
通讯作者：
Weaver, Paul M.
中科院分区：
文献类型：
--
作者：
Coburn, Broderick H.;Weaver, Paul M.
近年来，变刚度（VS）技术已被证明提供显着的潜在重量节省和/或性能增益的整体和加筋板结构时，屈曲是一个驱动因素。到目前为止，很少有关于VS三明治结构的工作报道。因此，半解析模型的基础上的里兹能量法的纤维转向VS面板的夹层板的屈曲。该模型捕捉全球和剪切卷曲不稳定性，并解释两种类型的屈曲响应观察到的模式切换之间。定量协议详细的三维有限元分析被发现是在13%以内。随后的参数和优化研究，这是许多实际的几何形状使用开发的模型进行，揭示了，虽然VS夹层板显示出显着的改善，在全球屈曲性能，他们遭受减少剪切卷曲性能相比，他们的直纤维同行。这种行为被认为是由于VS面板创建一个预屈曲载荷重新分布的区域局部超过临界剪切卷曲载荷，并诱导在减少面板水平载荷的短波长不稳定性。对于芯材横向剪切模量适中至较低的VS夹层板，剪切卷曲可能成为关键模式，从而降低相对于直纤维配置的性能优势。具有足够刚度的芯，从而防止剪切卷曲，当使用VS时，临界屈曲载荷显示出约80%的改善，然而，随着芯横向剪切模量的降低，这种改善减少到可以忽略的量。因此，在夹层板的设计中，横向剪切柔性和载荷重分布是必须仔细考虑的两个关键参数，以便在这种新颖的结构配置中充分利用VS的益处。(C)2016爱思唯尔有限公司版权所有
In recent years variable-stiffness (VS) technology has been shown to offer significant potential weight savings and/or performance gains for both monolithic and stiffened plate structures when buckling is a driving consideration. As yet, little work has been reported on VS sandwich structures. As such, a semi analytical model is developed based on the Ritz energy method for the buckling of sandwich panels with fibre-steered VS face-sheets. The model captures both global and shear crimping instabilities and is shown to explain both types of buckling responses observed and the mode switching between them. Quantitative agreement with detailed three-dimensional finite element analysis was found to be within 13%. Subsequent parametric and optimisation studies, which were performed for many practical geometries using the developed model, reveal that, whilst VS sandwich panels show a significant improvement in global buckling performance, they suffer a reduction in shear crimping performance when compared to their straight-fibre counterparts. This behaviour is found to be due to the VS face-sheets creating a pre-buckling load redistribution where regions locally exceed the critical shear crimping load and induce the short wavelength instability at a reduced panel level load. For VS sandwich panels with modest to low transverse shear moduli of the core, shear crimping can become the critical mode diminishing performance benefits relative to straight-fibre configurations. Cores with sufficient rigidity, thus preventing shear crimping, showed improvements in critical buckling load in the order of 80% when using VS, however this improvement reduces to a negligible amount with decreasing core transverse shear moduli. The transverse shear flexibility and load redistribution are thus two key parameters that must be considered carefully in the design of sandwich panels, in order to exploit the benefits of VS fully in this novel structural configuration. (C) 2016 Elsevier Ltd. All rights reserved.