基于复杂网络理论的颗粒力链网络的拓扑力学数值模拟

发布时间：2018-04-20 01:21

本文选题：复杂网络 + 三轴压缩　；参考：《湘潭大学》2017年硕士论文

【摘要】：土颗粒是自然界中最常见的一类颗粒,广泛的用于人类的生产建设之中,然而因为土具有高度的复杂性,所以人们对于其研究探索大部分还是处于试验阶段,通过试验来探究土的性质似乎成为目前最常见的方法。随着复杂网络理论的发展,其已经在诸如交通、管理、社交等领域得到了广泛的应用,同时离散元软件的发展也让我们对简化土颗粒的模拟变为现实,因此本文将用离散元软件模拟三轴压缩条件下简化沙质土颗粒,然后用复杂网络的方法对颗粒之间的接触力链网络进行分析。主要工作如下:1)本文首先应用离散元软件构建了三轴压缩条件下沙质土颗粒的力链无向网络模型,将颗粒中心视为网络的节点、与之接触且相互之间有正向力的两个节点视为网络的边。因为土颗粒体系的高度复杂性,所以对土颗粒进行了相当程度的简化,在一定的假设条件下,如不考虑土颗粒中水的影响和以及颗粒的粘性来建立模型。2)我们对同一粒径与不同粒径情形下的颗粒力链动态拓扑特性分别进行了模拟和分析,对于所构建的接触网络,本文使用pajek得到了复杂网络系统中三个重要参数:度、平均最短路径以及聚类系数。通过这些网络参数来描述颗粒内部的力链拓扑结构,结果表明颗粒的团聚现象随着演化的进行越来越明显,力链网络的传导能力不断增强。3)将颗粒系统中的所有颗粒看做是一个整体是远远不够的,他并不能代表具体的某一类颗粒网络的特性,所以我们还将颗粒进行了分类,本文通过力链强度的不同对颗粒的接触力链网络分成了强中弱三种不同的力链网络,同样用复杂网络来研究其内部的拓扑结构,发现强力链网络基本呈现链状形态,并且其平均路径最短,传递荷载的能力最强。
[Abstract]:Soil particles are the most common type of particles in nature, which are widely used in the production and construction of human beings. However, because of the high complexity of soil, most of its research and exploration are still in the experimental stage. Exploring the nature of soil through experiments seems to be the most common method at present. With the development of complex network theory, it has been widely used in many fields, such as transportation, management, social communication and so on. Meanwhile, the development of discrete meta-software has made the simulation of simplified soil particles a reality. Therefore, in this paper, the discrete element software is used to simulate the simplified sand soil particles under triaxial compression conditions, and then the contact force chain network between particles is analyzed by the method of complex network. The main work is as follows: (1) in this paper, the undirected network model of the force chain of sandy soil particles under triaxial compression is constructed by using discrete element software, and the center of the particle is regarded as the node of the network. Two nodes that are in contact with each other and have positive forces with each other are regarded as the edges of the network. Because of the high complexity of the soil particle system, the soil particle is simplified to a considerable extent, under certain hypothetical conditions, If we do not consider the influence of water in the soil particle and the viscosity of the particle to establish the model. (2) We simulate and analyze the dynamic topological characteristics of the force chain of the particle under the same particle size and different particle size respectively. For the contact network constructed, In this paper, pajek is used to obtain three important parameters in complex network system: degree, average shortest path and clustering coefficient. These network parameters are used to describe the topological structure of the force chain inside the particles. The results show that the agglomeration of particles becomes more and more obvious with the evolution of the particles. It's not enough to think of all the particles in the particle system as a whole. It's not enough to represent the properties of a particular type of particle network, so we've also classified the particles. In this paper, the contact chain network with different force chain strength is divided into three different force chain networks, which are strong, medium and weak. The topological structure of the network is also studied by using complex network, and it is found that the strong chain network is basically chain-like. And its average path is shortest, and the ability to transfer load is the strongest.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU41

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