高速冲击破碎问题的Hamilton粒子重构单元方法

项目名称： 高速冲击破碎问题的Hamilton粒子重构单元方法

项目编号： No.11502010

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 张晓天

作者单位： 北京航空航天大学

项目金额： 22万元

中文摘要： 高速冲击破碎问题广泛存在于航天器防护、火炮弹丸高速穿甲、在轨解体等工程实际问题中。这类问题实验难度大，研究其数值模拟技术能够有效揭示物理机理、缩短设计周期、降低成本。由于有限元与无网格方法各有优势，因此将两者相融合的算法是近年的一个研究热点。本项目拟提出一种新的高速冲击破碎模拟方法——Hamilton粒子重构单元方法。从能量角度建立高速冲击问题状态量演化方程，并将热传导和接触碰撞作用处理为系统非完整约束。显式迭代中首先对粒子进行积分，然后通过粒子重构单元，进而采用粒子与单元耦合算法计算固体本构关系。通过节点分离技术处理材料断裂与损伤演化过程。用连续单元表征连续材料，节点分离表征断裂，而纯粒子仅用于表征无法维持自身形状的畸变或相变材料。Hamilton粒子重构单元方法结合了Hamilton力学方法的优势以及单元粒子融合算法的优势，为工程中的高速冲击问题提供一种精度更高、适用性更强的预测手段。

中文关键词： 无网格法；有限元；耦合法；高速冲击；破碎

英文摘要： High velocity impact physics is widely used in many engineering areas, such as: spacecraft shielding, projectiles penetrating the target, on-orbit breakup, etc. It is difficult to carry out physical experiments to this kind of problems. Numerical investigation can expose the inherent physical mechanisms and reduce the design cycle and the cost. Since either the finite element method or meshfree particle method has its own advantages, the hybrid algorithm is the recent research hotspot. A new method for high velocity impact fragmentation simulation, Hamilton particle-finite element reconstruction method, is supposed to be proposed in this project. The states evolutionary equations are built from the perspective of energy. The thermal conduction and the collision forces are dealt with nonholonomic constraints. In the explicit iteration, the particles are integrated first; following that finite elements are reconstructed from the particles; and then the solid constitutive model is computed with the coupled algorithm of element and particle. Node separation technique is introduced to handle the material fracture and the damage evolution process. The continuum materials are represented with continuum elements; the fracture is reproduced with node separation; only the distorted and phase changed materials are represented by pure particles. Hamilton particle-finite element reconstruction method combines the advantages of both the Hamilton mechanics and the hybrid algorithm. It is a potential prediction scheme with higher accuracy and stronger applicability for high velocity impact fragmentation problems in the engineering design.

英文关键词： meshfree method;finite element;coupled method;high velocity imapct;fragmentation