弹体侵彻混凝土的FEM-SPH耦合算法研究

The problem of projectile penetration into concrete has always been the research focus for weapons development and engineering protection department. Numerical simulation is an important means of the penetration process and penetration mechanism study. The project is aim to develop high efficiency and high precision numerical method, and the coupled FEM-SPH algorithm is proposed for the simulation of the projectile penetration into concrete. The method combines the advantage of both FEM and SPH. During the calculation, it can automatically convert the elements to particles when FEM encounter some difficulties such as the element distortion. By studying some key issues such as the contact interface computations of different materials, and the method for dealing with the element-particle interface, a high accuracy and efficiency computational program is to be established. In the numerical simulation, reasonable material model is an important prerequisite for the effectiveness of the computational results. On the basis of theoretical analysis and experimental research, a new dynamic tensile damage model of concrete is to be developed. By inserting the material models to the program and improving the existing SPH method, the simulation of the concrete fracture will be more reasonable in the process of penetration, and the penetration images will be more close to actual. The development of the program can provide important guidance for people to study concrete penetration mechanism and structure protection design.

弹体侵彻混凝土问题一直都是武器研制和工程防护部门研究的重点，数值模拟是人们研究侵彻过程和侵彻机理的一种重要手段。本项目以发展高效高精度数值计算方法为目标，开展弹体侵彻混凝土问题的FEM-SPH耦合算法研究。该算法结合了有限元法计算效率高和光滑粒子法适宜处理大变形的优势，在计算过程中，当有限元法遇到困难（如单元发生畸变）时，能自动将单元转换为粒子参与计算。对耦合算法中不同材料界面的接触计算，以及单元与粒子界面的耦合计算等关键问题开展研究，开发具有较高精度和效率的计算程序。在混凝土侵彻模拟中，合理的材料模型是计算结果有效的重要前提，在理论分析和实验研究的基础上，提出一种新的混凝土动态拉伸损伤模型。通过引入材料模型并改进现有SPH方法，使程序能更加合理自然地模拟侵彻过程中混凝土的破碎、开裂，得到更接近实际的侵彻图像。该程序的开发可为人们研究混凝土抗侵彻机理和结构防护设计提供重要指导。

弹体侵彻混凝土问题一直都是武器研制和工程防护部门关注的重点，对侵彻过程和侵彻机理的研究在战斗部设计、毁伤效应评估等方面有重要意义。本项目以提高计算效率和计算精度为目标，开展弹体侵彻混凝土的FEM-SPH耦合算法研究。通过理论分析和实验测试，提出一种新的混凝土动态拉伸损伤模型。将该模型引入到混凝土HJC本构模型中，使模型能更全面地描述侵彻过程中混凝土的动态破坏现象。对现有SPH方法进行了改进，通过在粒子之间引入虚拟弹簧，并考虑损伤的影响，提出了一种模拟动态裂纹扩展的方法。结合光滑粒子法适宜处理大变形而有限元法计算效率高的优势，发展一种简洁高效的FEM-SPH耦合算法。初始时刻用有限元建模，当单元出现畸变满足转换条件时自动将单元节点转换为粒子参与计算，使用粒子接触算法来处理不同物质界面的相互作用。编制了相应计算程序，并引入混凝土本构和损伤模型，实现对侵彻过程的精确高效模拟。项目可以为研究混凝土抗侵彻机理和结构防护设计提供指导。