Numerical analysis of strain rate sensitivity in ball indentation on cohesive powder Beds
Numerical analysis of strain rate sensitivity in ball indentation on cohesive powder Beds
复制标题
粘性粉末床上球压痕应变率敏感性的数值分析
DOI：
10.1016/j.ces.2014.10.026
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发表时间：
2015
影响因子：
4.7
通讯作者：
Pasha M
中科院分区：
文献类型：
--
作者：
Pasha M
在粉末床的剪切变形超过准静态制度的剪切应力是依赖于应变率。大量的工作已经报道了大颗粒的快速斜槽流，但中间状态尚未得到广泛解决，特别是在粘性粉末的情况下。然而，在工业粉末工艺中，粉末流通常处于中间状态。在本工作中，试图调查的应力在一个组装的粘性球形颗粒的应变率在球压痕使用的离散单元法的敏感性。该技术最近被提出作为一种快速简便的方法来评估粘性粉末的流动性。结果表明，在自由表面上进行球压痕的床层内的硬度、偏应力和静水应力取决于压痕应变率。这些应力在无量纲应变率为1时几乎是恒定的，这与传统剪切单元测试方法的趋势一致，尽管波动开始从无量纲应变率0.5开始增加。对于大于1的无量纲应变速率，这些应力增加，其中硬度的增加是最显著的。这些趋势与文献中确定的Couette器械相关。然而，由于剪切变形带的几何形状的差异，制度的应变率边界的定量值不同。然而，这表明了压痕技术在捕获内聚粉末流的动力学方面的能力。
In the shear deformation of powder beds beyond the quasi-static regime the shear stress is dependent on the strain rate. Extensive work has been reported on the rapid chute flow of large granules but the intermediate regime has not been widely addressed particularly in the case of cohesive powders. However in industrial powder processes the powder flow is often in the intermediate regime. In the present work an attempt is made to investigate the sensitivity of the stresses in an assembly of cohesive spherical particles to the strain rate in ball indentation using the Distinct Element Method. This technique has recently been proposed as a quick and easy way to assess the flowability of cohesive powders. It is shown that the hardness, deviatoric and hydrostatic stresses within a bed, subjected to ball indentation on its free surface, are dependent on the indentation strain rate. These stresses are almost constant up to a dimensionless strain rate of unity, consistent with trends from traditional methods of shear cell testing, though fluctuations begin to increase from a dimensionless strain rate of 0.5. For dimensionless strain rates greater than unity, these stresses increase, with the increase in hardness being the most substantial. These trends correlate well with those established in the literature for the Couette device. However the quantitative value of the strain rate boundary of the regimes differs, due to differences in the geometry of shear deformation bands. Nevertheless, this shows the capability of the indentation technique in capturing the dynamics of cohesive powder flow.
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影响因子：
5.2
作者：
M. Pasha;C. Hare;A. Hassanpour;M. Ghadiri
通讯作者：
M. Pasha;C. Hare;A. Hassanpour;M. Ghadiri
单轴压实试验机与剪切试验机表征粉末流动性的比较
影响因子：
4.1
作者：
Luca Parrella;D. Barletta;R. Boerefijn;M. Poletto
通讯作者：
M. Poletto
通过测试少量弱压块来表征粘性粉末的流动性
影响因子：
3.5
作者：
Chuan Ting Wang;A. Hassanpour;M. Ghadiri
通讯作者：
M. Ghadiri
影响因子：
3.5
作者：
Luding, Stefan
通讯作者：
Luding, Stefan
影响因子：
5.2
作者：
A. Hassanpour;U. Zafar;M. Pasha;C. Hare;M. Ghadiri
通讯作者：
M. Ghadiri