超弹性薄膜与可压缩基底双层结构表面失稳分析
发布时间：2019-03-15 13:59
【摘要】：当上层超弹性硬质薄膜和下层可膨胀基底构成的双层结构受压时,薄膜的自由表面可通过形成褶皱降低系统能量.研究表明,上下两层的模量比不同时,上层弹性硬质薄膜将表现出不同的表面失稳模式.本文提出了一种新颖的方法可有效抑制双层软材料的表面失稳,即改变基底材料的泊松比,这种方法同时适用于不具有应变硬化的软材料.首先基于Neo-Hookean模型发展了小变形条件下双层结构表面失稳的理论模型,通过半解析的方法得到了表面失稳的临界应变;然后通过有限元计算与模拟,进一步验证了负泊松比基底可延缓表面失稳.结果表明:(1)当双层结构基底泊松比为正且趋于0.5(不可压缩)时,双层结构在较小的压缩应变下出现表面失稳;(2)当基底的泊松比为负且趋于-1时,可被压缩至46%而不出现表面失稳,即可膨胀基底能有效抑制薄膜的表面失稳.本文发展的方法及主要结果可为延展性电子器件的设计提供指导.
[Abstract]:When the superelastic hard film in the upper layer and the double-layer structure composed of the expandable substrate in the lower layer are subjected to compression, the free surface of the film can reduce the energy of the system through the formation of folds. The results show that when the modulus ratio of the upper and lower layers is different, the elastic hard films in the upper layer will exhibit different surface instability modes. In this paper, a novel method is proposed to effectively suppress the surface instability of double layer soft materials, that is, to change the Poisson's ratio of substrate materials. This method is also suitable for soft materials without strain hardening. Firstly, the theoretical model of surface instability of double-layer structures under small deformation is developed based on Neo-Hookean model, and the critical strain of surface instability is obtained by semi-analytical method. Then through the finite element calculation and simulation, it is further verified that the negative Poisson ratio substrate can delay the surface instability. The results show that: (1) when the Poisson ratio of the double-layer structure is positive and tends to 0.5 (incompressible), the surface instability of the double-layer structure appears under small compression strain; (2) when the Poisson ratio of the substrate is negative and tends to-1, it can be compressed to 46% without surface instability, so the expansive substrate can effectively restrain the surface instability of the thin film. The development method and main results of this paper can provide guidance for the design of extendable electronic devices.
【作者单位】： 重庆大学航空航天学院;
【基金】：国家自然科学基金资助项目(11472065)
【分类号】：O343.9
，
本文编号：2440695
[Abstract]:When the superelastic hard film in the upper layer and the double-layer structure composed of the expandable substrate in the lower layer are subjected to compression, the free surface of the film can reduce the energy of the system through the formation of folds. The results show that when the modulus ratio of the upper and lower layers is different, the elastic hard films in the upper layer will exhibit different surface instability modes. In this paper, a novel method is proposed to effectively suppress the surface instability of double layer soft materials, that is, to change the Poisson's ratio of substrate materials. This method is also suitable for soft materials without strain hardening. Firstly, the theoretical model of surface instability of double-layer structures under small deformation is developed based on Neo-Hookean model, and the critical strain of surface instability is obtained by semi-analytical method. Then through the finite element calculation and simulation, it is further verified that the negative Poisson ratio substrate can delay the surface instability. The results show that: (1) when the Poisson ratio of the double-layer structure is positive and tends to 0.5 (incompressible), the surface instability of the double-layer structure appears under small compression strain; (2) when the Poisson ratio of the substrate is negative and tends to-1, it can be compressed to 46% without surface instability, so the expansive substrate can effectively restrain the surface instability of the thin film. The development method and main results of this paper can provide guidance for the design of extendable electronic devices.
【作者单位】： 重庆大学航空航天学院;
【基金】：国家自然科学基金资助项目(11472065)
【分类号】：O343.9
，
本文编号：2440695
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