论文标题

刚性和高度可变形颗粒的混合物的压实:微型机械模型

Compaction of mixtures of rigid and highly deformable particles: a micro-mechanical model

论文作者

Cárdenas-Barrantes, Manuel, Cantor, David, Barés, Jonathan, Renouf, Mathieu, Azéma, Emilien

论文摘要

我们通过非平滑接触动力学方法(NSCD)分析了由刚性和可变形不可压缩颗粒组成的混合物的各向同性压实。使用经典有限元元素使用超弹性的新hookean构态定律模拟可变形的身体。对于从完全刚性到完全可变形颗粒的混合物,我们表征了堆积分数,弹性模量的演变,以及当变化的摩擦粒子间系数变化时,连通性作为所施加应力的函数。我们首先表明,包装分数增加并渐近地趋向于最大值$ ϕ_ {max} $,这取决于混合物比和颗粒间摩擦。批量模量还显示出随着包装的分数而增加,并且在接近$ ϕ_ {max} $时发散。从颗粒应力张量的微型机械表达中,我们开发了一个模型,以描述压实行为是施加压力的函数,可变形颗粒的年轻模量和混合物比的函数。散装方程也来自压实方程。该模型介绍了在压缩下的单个可变形粒子的表征,以及连通性和填充分数之间的幂律关系。由定义明确的物理量设置的压实模型从干扰点提高到非常高的密度,从而使我们能够直接预测$ ϕ_ {max} $,这是混合比率和摩擦系数的函数的直接预测。

We analyze the isotropic compaction of mixtures composed of rigid and deformable incompressible particles by the non-smooth contact dynamics approach (NSCD). The deformable bodies are simulated using a hyper-elastic neo-Hookean constitutive law by means of classical finite elements. For mixtures that varied from totally rigid to totally deformable particles, we characterize the evolution of the packing fraction, the elastic modulus, and the connectivity as a function of the applied stresses when varying inter-particle coefficient of friction. We show first that the packing fraction increases and tends asymptotically to a maximum value $ϕ_{max}$, which depends on both the mixture ratio and the inter-particle friction. The bulk modulus is also shown to increase with the packing fraction and to diverges as it approaches $ϕ_{max}$. From the micro-mechanical expression of the granular stress tensor, we develop a model to describe the compaction behavior as a function of the applied pressure, the Young modulus of the deformable particles, and the mixture ratio. A bulk equation is also derived from the compaction equation. This model lays on the characterization of a single deformable particle under compression together with a power-law relation between connectivity and packing fraction. This compaction model, set by well-defined physical quantities, results in outstanding predictions from the jamming point up to very high densities and allows us to give a direct prediction of $ϕ_{max}$ as a function of both the mixture ratio and the friction coefficient.

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