Abstract Cavitation in rubber-like materials is commonly known as sudden void growth under hydrostatic tension till material failure occurs. Experimental investigations of adhesives, e.g. structural silicones accounting for cavitation in combination with the numerical treatment of this phenomenon are rare. Accordingly, this paper presents a micro-mechanically motivated constitutive model accounting for isotropic void growth. It was developed based on numerical homogenization schemes of a cube with an incompressible matrix containing a single, vacuous void in the center. To differentiate whether an initial void is growing, a new developed void growth criterion is presented. The void growth criterion was coupled with the new developed volumetric Helmholtz free energy function to extend the classical volumetric-deviatoric split to large volume strains. Experiments were performed with a structural silicone under uniaxial tension as well as so-called pancake tests and compared with the new developed volumetric constitutive model accounting for isotropic cavitation. To observe qualitatively cavitation during experiments, a new testing device was developed, which enables one to characterize this damaging effect of the adhesive bonding. The numerical validation shows a good approximation of the experimental results. In order to improve the simulation results, an optimization study on the constitutive parameters was conducted.

中文翻译：

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解释有限应变下各向同性空化的新型体积亥姆霍兹自由能函数

摘要 橡胶类材料中的气穴现象通常是指在静水张力作用下空隙突然增大直至材料失效。粘合剂的实验研究，例如考虑空化的结构有机硅，结合这种现象的数值处理是罕见的。因此，本文提出了一种解释各向同性空隙增长的微观机械本构模型。它是基于立方体的数值均匀化方案开发的，该立方体具有不可压缩的矩阵，中心包含一个单一的空洞。为了区分初始空隙是否在增长，提出了一个新开发的空隙增长标准。空隙增长标准与新开发的体积亥姆霍兹自由能函数相结合，将经典的体积偏分分裂扩展到大体积应变。在单轴拉伸下使用结构硅树脂进行实验以及所谓的煎饼测试，并与新开发的体积本构模型进行比较，以解释各向同性空化。为了在实验过程中定性地观察空化现象，开发了一种新的测试设备，它可以表征粘合剂粘合的这种破坏作用。数值验证显示了实验结果的良好近似。为了改善仿真结果，对本构参数进行了优化研究。在单轴拉伸下用结构硅树脂进行实验以及所谓的煎饼测试，并与新开发的体积本构模型进行比较，以解释各向同性空化。为了在实验过程中定性地观察空化现象，开发了一种新的测试设备，它可以表征粘合剂粘合的这种破坏作用。数值验证显示了实验结果的良好近似。为了改善仿真结果，对本构参数进行了优化研究。在单轴拉伸下用结构硅树脂进行实验以及所谓的煎饼测试，并与新开发的体积本构模型进行比较，以解释各向同性空化。为了在实验过程中定性地观察空化现象，开发了一种新的测试设备，它可以表征粘合剂粘合的这种破坏作用。数值验证显示了实验结果的良好近似。为了改善仿真结果，对本构参数进行了优化研究。这使人们能够表征粘合剂粘合的这种破坏性影响。数值验证显示了实验结果的良好近似。为了改善仿真结果，对本构参数进行了优化研究。这使人们能够表征粘合剂粘合的这种破坏性影响。数值验证显示了实验结果的良好近似。为了改善仿真结果，对本构参数进行了优化研究。