基于增强的物质点法的非均质弹性材料仿真方法研究  

Research of Heterogeneous Elastic Material Simulation Method Based on Enhanced MPM

作　　者：赵静[1,2] 唐勇 李胜[3,4] 汪国平 ZHAO Jing;TANG Yong;LI Sheng;WANG Guo-Ping(College of Information Science and Engineering,Yanshan University,Qinhuangdao,Hebei 066004;School of Electronics Engineering and Computer Science,Peking University,Beijing 100871;The Key Laboratory for Computer Virtual Technology and System Integration of Hebei Province,Qinhuangdao,Hebei 066004;Beijing Engineering Research Center for Virtual Simulation and Visualization,Beijing 100871)

机构地区：[1]燕山大学信息科学与工程学院,河北秦皇岛066004 [2]河北省计算机虚拟技术与系统集成重点实验室,河北秦皇岛066004 [3]北京大学信息科学技术学院,北京100871 [4]北京市虚拟仿真与可视化工程研究中心,北京100871

出　　处：《计算机学报》2018年第11期2598-2611,共14页Chinese Journal of Computers

基　　金：国家自然科学基金项目(61232014;61421062;61472010);国家科技支撑项目(2015BAK01B06)资助~~

摘　　要：在基于物理的仿真领域,近几年流行的物质点法已经成为一种越来越重要的仿真方法.物质点法已经可以仿真雪、物质状态变化、颗粒状的沙子以及粘弹性的泡沫等物理现象.现有的各种复杂物理现象的模拟已经展示了物质点法作为一种通用的求解方法的潜质,然而对于仿真形变体尤其是自然界普遍存在的非均质材质还存在一些不足.当同一网格内部包含多种材质的粒子时,由于背景网格与粒子之间的插值只考虑粒子的几何位置而不包含物质属性信息,导致不同属性的粒子在网格内部表现为"平均化"的运动趋势.为了改进传统物质点法模拟多种材质的缺陷,该文提出了一种模拟非均质弹性材料的仿真方法.首先,在预处理过程中将仿真物体离散表示成粒子,针对物质的不同属性粒子的分布,建立物质边界并确定边界粒子,仿真过程中动态更新边界粒子的位置;其次,引入粒子影响域,区分网格内部具有不同属性的粒子,增加网格内部计算自由度;最后,提出一个判断准则,根据物质边界粒子的位置判定仿真粒子是在背景计算网格上求解还是粒子区域上求解.实验结果表明,利用改进的物质点法能够有效地模拟非均质材质弹性体的形变.与有限元法相比,该文方法在模拟非均质弹性体时可以获得相似的效果,并且在模拟拓扑结构变化的问题以及碰撞处理上更有优势.For recent years,the material point method(MPM)has been proved to be an important simulation method in the physically-based animation fields.Its capability is well demonstrated with compelling visual simulations of snow,melting and solidifying materials,porous materials like sand and viscoelastic materials like foam,etc.The existing complicate physical phenomenon exhibits its potential to be a unified solver,while it still has some limitations for the elastic materials,especially for the heterogeneous materials which are more general in the nature world.Since the interpolation between the background grids and the particles are based only on the geometry position of the particles without considering of the material properties,the movement of particles will act as an“average”effect in one grid.To improve the limitation of complex materials with the traditional MPM,we propose a simulation method for heterogeneous elastic materials.Firstly,in the precomputation process,the simulation object is discretized as particles and the material boundaries and the corresponding boundary particles are established according to the distribution of the particles with different properties.The locations of the boundary particles are updated dynamically during the simulation process.Secondly,we introduce the particle impact domain to separate the different particles which increase the computing DOF(Degree Of Freedom)inside the grid.The interpolation between the grids and the particles in the traditional MPM has been extended to two steps.The particle domain acts as an intermediate process to connect the grids and the particles.Finally,according to the position of the material boundaries,we present a criterion to judge that the calculation of the simulation particles is on the background computing grids or on the particle domains.In the simulation process,we record the enhanced background grids by tracing the boundary particles.The particles in the signed background grids are set to the enriched particles,which are computed on thei

关 键 词：物质点法 非均质弹性材料 粒子区域 物质边界 数值断裂 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]