Critical contact stiffness concept and simulation of crack generation in particle models of large length-scales
Critical contact stiffness concept and simulation of crack generation in particle models of large length-scales
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DOI：
10.1016/j.compgeo.2008.03.001
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发表时间：
2009
影响因子：
5.3
通讯作者：
Chong-bin Zhao;B. Hobbs;A. Ord;S. Peng
中科院分区：
文献类型：
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作者：
Chong-bin Zhao;B. Hobbs;A. Ord;S. Peng
当用粒子模拟方法模拟大尺度问题时，如地质学中的地壳尺度问题，需要在粒子模型中考虑重力效应。为了适当地考虑重力效应，对颗粒的接触刚度有一个最小值要求，从而可以避免意外的颗粒重叠。这个最小值被称为由于重力效应的颗粒的临界接触刚度。本文利用二维颗粒模型底部颗粒的垂直力平衡条件，成功地导出了确定颗粒临界接触刚度的理论公式。对于由单位厚度的圆形颗粒组成的二维颗粒模型，当任意两个颗粒之间使用线弹性接触模型时，颗粒的临界接触刚度与颗粒材料的临界弹性模量之间存在关系。由于大多数地壳岩石的弹性模量都大于相应的颗粒材料的临界弹性模量，因此，理论上证明了基于任意两个颗粒之间的线弹性接触模型的颗粒模拟方法适合于在大尺度的颗粒模型中模拟重力效应。有关模拟结果表明，粒子模拟方法在模拟脆性地壳岩石中的自发裂纹产生模式方面是有效的。
When the particle simulation method is used to simulate large length-scale problems, such as crustal length-scale problems in the field of geology, it is necessary to include gravity effect into the particle model. To consider gravity effect appropriately, there is a minimum value requirement for the contact stiffness of a particle so that unexpected particle overlap can be avoided. This minimum value is called the critical contact stiffness of a particle due to gravity effect. Using the vertical force equilibrium condition of a particle at the bottom of a two-dimensional particle model, a theoretical formula has been successfully derived for determining the critical contact stiffness of the particle in this paper. For the two-dimensional particle model consisting of circular particles of unit thickness, there is a relationship between the critical contact stiffness of a particle and the critical elastic modulus of the particle material when a linear-elastic-contact model between any two particles is used. Since the elastic moduli of most crustal rocks are greater than the corresponding critical elastic modulus of the particle material, it has been theoretically demonstrated that the particle simulation method, which is based on the linear-elastic-contact model between any two particles, is suitable for simulating gravity effect within the particle model of a large length-scale. The related simulation results have demonstrated the usefulness of the particle simulation method for simulating spontaneous crack generation patterns within brittle crustal rocks.