考虑颗粒破碎的粗粒料力学特性数值试验初步研究

发布时间：2018-03-02 03:06

本文关键词： 粗粒料力学特性数值试验颗粒破碎 DDA 计算参数　出处：《长江科学院》2014年硕士论文　论文类型：学位论文

【摘要】：粗粒料是由大小不等、性质不一的岩石颗粒彼此充填而成的散粒集合体，在荷载作用下易发生颗粒破碎。颗粒破碎影响了粗粒料的力学特性。由于试验条件的限制，物理试验结果的准确性和普遍性受到影响。数值试验则不受此限制，可作为物理试验的有效补充手段。本文采用二维非连续变形分析方法（DDA）进行考虑颗粒破碎的粗粒料力学特性数值试验，主要研究工作和研究成果如下：（1）建立了粗粒料力学特性DDA数值试验模型，研究了接触刚度、时间步长、阻尼等计算参数的合理取值。（2）基于ANSYS软件的有限元前处理技术，对粗粒料颗粒进行块体细分，满足了模拟颗粒破碎的需要。（3）考虑到粗粒料力学特性数值试验计算量大，将块雅克比预处理共轭梯度法和并行计算技术用于求解DDA方程组，提高了计算速度。（4）考虑颗粒破碎的数值试验成果与三轴试验成果总体接近，，而不考虑颗粒破碎的应力-应变曲线明显高于考虑颗粒破碎的曲线，且与三轴试验曲线的差异大，说明考虑颗粒破碎是必要的。以上研究工作为DDA在粗粒料力学特性研究中的应用奠定了基础。
[Abstract]:Coarse grain is a granular aggregate filled with rock particles of different sizes and different properties, which is liable to be broken under load. Particle breakage affects the mechanical properties of coarse grain, due to the limitation of test conditions. The accuracy and universality of physical test results are affected. Numerical tests are not subject to this limitation. In this paper, a two-dimensional discontinuous deformation analysis method is used to carry out numerical experiments on the mechanical properties of coarse grain considering particle breakage. The main research work and results are as follows:. 1) the DDA numerical test model of the mechanical properties of coarse grain is established, and the reasonable calculation parameters such as contact stiffness, time step size and damping are studied. 2) based on the finite element preprocessing technology of ANSYS software, the coarse granular particles are subdivided into blocks, which can meet the needs of simulating particle breakage. In view of the large amount of calculation in the numerical test of the mechanical properties of coarse grain, the block Jacobian preconditioning conjugate gradient method and the parallel computing technique are used to solve the DDA equations, and the calculation speed is improved. (4) the numerical test results considering particle breakage are in general close to those of triaxial test, but the stress-strain curve without considering particle breakage is obviously higher than that considering particle breakage, and there is a great difference from the triaxial test curve. It shows that it is necessary to consider particle breakage. The above work lays a foundation for the application of DDA in the study of the mechanical properties of coarse granular materials.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV641.4;TV41

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