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Yield criterion and finite strain behavior of random porous isotropic materials
European Journal of Mechanics - A/Solids ( IF 4.1 ) Pub Date : 2020-10-09 , DOI: 10.1016/j.euromechsol.2020.104143
J. Hure

The mechanical response of isotropic elastoplastic materials containing random distributions of initially spherical voids is investigated computationally based on Fast Fourier Transform simulations. Numerical limit-analysis simulations at constant stress triaxiality allow to determine the yield surfaces, leading in particular to the determination of a Representative Volume Element size for the onset of coalescence/inhomogeneous yielding. Moreover, two different coalescence regimes are observed that differ by the presence of shearing. The yield surfaces are found to be consistent with the combination of two models proposed in the literature, a GTN-type model calibrated for homogeneous yielding of random porous materials and an inhomogeneous yielding model accounting for both coalescence with or without shear. Finite strain simulations performed for different hardening moduli and stress triaxialities under axisymmetric loading conditions confirm the existence of a RVE up to the onset of inhomogeneous yielding. Coalescence strains are found to be significantly smaller for random porous materials than for periodic distribution of voids. A homogenized model is finally proposed that reproduces quantitatively the behavior of isotropic elastoplastic materials containing random distributions of voids under finite strains.



中文翻译:

随机多孔各向同性材料的屈服准则和有限应变行为

基于快速傅里叶变换模拟,对包含初始球形空隙随机分布的各向同性弹塑性材料的机械响应进行了研究。恒定应力三轴性下的数值极限分析模拟可以确定屈服面,特别是可以确定开始发生聚结/不均匀屈服的代表体积单元尺寸。此外,观察到两种不同的合并方案,它们因剪切的存在而不同。发现屈服面与文献中提出的两个模型的组合相一致,GTN型模型针对随机多孔材料的均匀屈服进行了校准,而非均匀屈服模型则考虑了在有或没有剪切作用下的聚结。在轴对称载荷条件下对不同的硬化模量和应力三轴性进行的有限应变模拟证实,直到不均匀屈服开始,RVE的存在。发现对于随机多孔材料,聚结应变明显小于空隙的周期性分布。最后提出了一个均质模型,该模型定量地再现了各向同性弹塑性材料在有限应变下包含随机分布的空隙的行为。

更新日期:2020-10-12
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