Finite element simulation of the pressure dip in sandpiles
Finite element simulation of the pressure dip in sandpiles
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DOI：
10.1016/j.ijsolstr.2012.12.006
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发表时间：
2013-03
影响因子：
3.6
通讯作者：
Jun Ai;Jian-Fei Chen;Jin Y. Ooi
中科院分区：
文献类型：
--
作者：
Jun Ai;Jian-Fei Chen;Jin Y. Ooi
许多工业散装固体通常储存在通过从上方沉积而逐渐形成的开放式堆料中。关于这种简单桩的一个经典现象是观察到顶点下方的基底上的垂直压力中的显著压力下降，这是违反直觉的，因为这是可能预期最大压力的位置。在过去的几十年里，已经进行了大量的实验，分析和数值研究来调查这个问题，但对这个问题的全面理解仍然是难以捉摸的。成桩过程中产生的力学各向异性最近被认为是压力下降的主要原因。然而，最近的有限元法（FEM）的研究预测的压力下降下的顶点使用各向同性材料模型。文献回顾表明，缺乏了解的潜在机制和各种因素的作用，预测的压力下降，如渐进的网格激活，应力依赖性的模量和塑性破坏参数。本文的目的是研究这些因素的影响，通过模拟一组锥形沙堆实验形成的刚性基础上集中沉积。结果表明，在不考虑材料各向异性的情况下，可以预测显著的压力下降。然而，在研究的弹塑性模型的范围内，似乎预测压力倾向需要考虑施工过程和相关的塑性变形的模型。增强的应力硬化弹性显著地增强了倾斜的程度。结果表明，一个更大的动员的基础剪切牵引是一个重要的机制，在增强的反作用，导致一个显着的中心压力下降。
Many industrial bulk solids are commonly stored in open stockpiles that are progressively formed by depositing from above. A classic phenomenon concerning such simple piles is the observation of a significant pressure dip in the vertical pressure on the base underneath the apex which is counter-intuitive as this is the location where a maximum pressure might be expected. Numerous experimental, analytical and numerical studies have been conducted to investigate this problem over the last few decades, but a comprehensive understanding of the problem remains elusive. Mechanical anisotropy developed during pile formation process has recently been suggested to be the main cause of the pressure dip. However, more recent finite element method (FEM) studies have predicted a pressure dip beneath the apex using isotropic material models. The review of the literature shows a lack of understanding of the underlying mechanism and the roles of various factors on the prediction of the pressure dip, such as the progressive mesh activation, stress dependency of modulus and plastic failure parameters. The aim of this paper is to investigate the effects of these factors by modelling a set of conical sandpile experiments formed on a rigid base by concentrated deposition. The results show that significant pressure dip can be predicted without considering material anisotropy. However, within the realm of elasto-plastic models investigated, it appears that the prediction of pressure dip requires a model considering the construction process and the associated plastic deformation. Incorporating stress-hardening elasticity enhances significantly the extent of the dip. The results demonstrate that a greater mobilisation of the base shear traction is an important mechanism in enhancing the arching effect that leads to a significant central pressure dip.