Micromechanical analysis of cohesive granular materials using the discrete element method with an adhesive elasto-plastic contact model
Micromechanical analysis of cohesive granular materials using the discrete element method with an adhesive elasto-plastic contact model
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DOI：
10.1007/s10035-014-0506-4
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发表时间：
2014-06-01
期刊：
影响因子：
2.4
通讯作者：
Ooi, Jin Y.
中科院分区：
文献类型：
--
作者：
Thakur, Subhash C.;Morrissey, John P.;Ooi, Jin Y.
为实现粘性粉末流动性的定量预测，提出了三维非球形颗粒的粘性弹塑性接触离散元模型。模拟已经进行了单轴固结，然后无侧限压缩破坏使用该模型。该模型已被证明是能够预测的实验流动功能（无侧限抗压强度与先前的固结应力）的石灰石粉已被选为参考固体在欧洲广泛的PARDEM研究网络。模型中的接触塑性显着影响的流动性，从而产生令人满意的计算的粘性颗粒材料的行为是必不可少的。该模型预测了归一化无侧限抗压强度与配位数和固相分数的乘积之间的线性关系。这种线性关系符合颗粒团聚体拉伸强度的Rumpf模型。即使当接触粘附力被迫保持不变，增加无侧限强度所产生的应力固结仍然是预测，这有其起源的接触塑性导致微观结构的演变的配位数。填充的孔隙率预计将增加的接触粘附力的增加。在侧限压缩下，孔隙率降低更逐渐为负载依赖的粘附相比，恒定的粘附。结果表明，粘结力对极限摩擦力的贡献对体积无侧限强度有显著影响。结果提供了新的见解，并提出了一个基于微观力学的措施，用于表征粘性颗粒材料的强度和流动性。
An adhesive elasto-plastic contact model for the discrete element method with three dimensional non-spherical particles is proposed and investigated to achieve quantitative prediction of cohesive powder flowability. Simulations have been performed for uniaxial consolidation followed by unconfined compression to failure using this model. The model has been shown to be capable of predicting the experimental flow function (unconfined compressive strength vs. the prior consolidation stress) for a limestone powder which has been selected as a reference solid in the Europe wide PARDEM research network. Contact plasticity in the model is shown to affect the flowability significantly and is thus essential for producing satisfactory computations of the behaviour of a cohesive granular material. The model predicts a linear relationship between a normalized unconfined compressive strength and the product of coordination number and solid fraction. This linear relationship is in line with the Rumpf model for the tensile strength of particulate agglomerate. Even when the contact adhesion is forced to remain constant, the increasing unconfined strength arising from stress consolidation is still predicted, which has its origin in the contact plasticity leading to microstructural evolution of the coordination number. The filled porosity is predicted to increase as the contact adhesion increases. Under confined compression, the porosity reduces more gradually for the load-dependent adhesion compared to constant adhesion. It was found that the contribution of adhesive force to the limiting friction has a significant effect on the bulk unconfined strength. The results provide new insights and propose a micromechanical based measure for characterising the strength and flowability of cohesive granular materials.