论文标题
随机多孔各向同性材料的产量标准和有限应变行为
Yield criterion and finite strain behavior of random porous isotropic materials
论文作者
论文摘要
基于快速的傅立叶变换模拟，对最初球形空隙的随机分布进行了随机分布的各向同性弹性材料的机械响应。恒定应力三轴性的数值极限分析模拟允许确定屈服表面，特别是确定了代表性的体积元素大小，用于合并 /不均匀屈服的发作。此外，观察到两个不同的聚结状态因剪切的存在而有所不同。发现屈服表面与文献中提出的两个模型的组合是一致的，该模型是一种校准的GTN型模型，用于均质的随机多孔材料，而无与伦比的屈服模型，占合并有或没有剪切的融合的不均匀屈服模型。在轴对称载荷条件下，针对不同硬化模量和应力三轴进行的有限应变模拟证实了在不均匀屈服开始之前的rve。对于随机多孔材料而言，合并菌株的合并菌株明显小于空隙的周期性分布。最终提出了一个均质模型，该模型可定量地重现各向同性弹性塑料材料的行为，该材料含有有限菌株下的空隙的随机分布。
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.
