仿珍珠母陶瓷/聚合物复合板抗弹性能模拟的高精度FEM-SPH耦合法及其应用研究

Nacre-like ceramic/polymer composites mimic internal structures and toughening mechanisms of nacre. They can overcome the poor toughness of ceramic and have promising potential in application to protective structures. The study of their ballistic performance is still in the early stage and mainly employs finite element method (FEM)–based simulation. However, FEM simulation suffers from deficiencies such as element distortion and poor accuracy for the study. Besides, existing studies are limited to ballistic performance under penetration of rigid projectiles, and effects of projectile deformation and shape as well as impact condition are not clearly explored. In this project, a surface-to-surface contact algorithm is firstly proposed to improve the contact treatment in smoothed particle hydrodynamics (SPH) method, and a modified SPH method for penetration simulation is obtained. Then, techniques for establishing FEM–SPH coupling model of nacre-like ceramic/polymer composite plates penetrated by projectiles are studied. A general surface-to-surface contact algorithm and a cohesive interface algorithm are constructed to treat all kinds of contact interfaces and cohesive interfaces, respectively, in the FEM-SPH coupling model. Relevant constitutive models and failure criterion for cohesive interface are implemented. A FEM-SPH coupling method of high accuracy is developed for simulating ballistic performance of nacre-like ceramic/polymer composite plate to overcome the deficiencies of FEM. The reliability of the developed method is validated by ballistic performance test. Finally, the FEM-SPH coupling method is applied to simulate ballistic performance of nacre-like ceramic/polymer composite plates under penetration of deformable projectiles. Effects of internal structure of target plate, projectile shape and impact condition are systematically analyzed.

仿珍珠母陶瓷/聚合物复合材料模仿珍珠母的内部结构和增韧机制，能克服陶瓷韧性差的缺陷，在防护结构中应用前景很好。其抗弹性能研究处于起步阶段，以FEM模拟为主，但FEM模拟存在网格畸变、精度不高等缺点。且目前的研究局限于刚性弹侵彻下的抗弹性能，对弹体变形、形状和入射条件的影响缺乏深入认识。为此，本项目首先提出面-面型SPH接触算法，提高SPH的接触计算精度，开发模拟侵彻问题的改进SPH法。然后，研究弹体侵彻仿珍珠母陶瓷/聚合物复合板的FEM-SPH耦合建模技术，构造耦合模型中各类接触界面的统一面-面型接触算法及粘结界面算法，嵌入相关本构模型和界面失效准则，开发模拟仿珍珠母陶瓷/聚合物复合板抗弹性能的高精度FEM-SPH耦合法，克服FEM的缺陷，并通过抗弹性能试验验证其可靠性。最后，应用其模拟变形弹侵彻下仿珍珠母陶瓷/聚合物复合板的抗弹性能，系统地分析靶板内部结构、弹体形状和入射条件的影响。

陶瓷具有重量轻、强度高、硬度大等优点，但其韧性差。基于脆性陶瓷和聚合物等延性材料，模仿珍珠母的微观结构和增韧机制，设计仿珍珠母复合材料与结构，克服陶瓷韧性差的缺陷，为高性能冲击防护材料与结构开发提供了重要途径。项目开展了仿珍珠母复合板抗冲击性能的高精度数值模拟方法研究。构建了基于重构表面的面-面型SPH接触算法，提出了新型的光滑长度更新算法和粒子近似修正方法，提高了SPH法的计算精度和稳定性。构建了模拟粘结界面的FEM-SPH耦合算法，建立了模拟仿珍珠母复合板抗冲击性能的FEM-SPH耦合法，可以有效地模拟复合板中脆性材料的破碎和界面脱粘行为；应用其开展了仿珍珠母复合板的冲击损伤模拟，得到了复合板的相关参数和冲击条件对其冲击损伤的影响规律。项目建立了仿珍珠母复合板的参数化建模方法，开发了相应的软件模块，提供了一种高效的途径来建立仿珍珠母复合板抗冲击性能分析的计算模型。基于数值模拟，系统地研究了仿珍珠母陶瓷/聚脲复合板在弹体高速冲击下的性能，揭示了内部结构对其抗弹性能的影响规律，获得了不同弹体形状和入射条件下的抗弹性能。开展了陶瓷板和仿珍珠母陶瓷/聚脲复合板的弹道冲击试验，捕获了靶板的高速冲击破坏过程，获得了弹体剩余速度、损伤面积等关键的抗弹性能参数，对复合板的抗弹性能进行了试验评估；同时，开展了仿珍珠母陶瓷/聚脲复合板的低速冲击实验，结合实验和数值模拟分析了复合板的损伤特性和机理。项目还对陶瓷/聚脲层叠复合板以及由陶瓷与其他延性材料组成的仿珍珠母复合板的抗弹性能进行了数值模拟研究。项目研究获得的仿珍珠母复合板的抗弹性能数据、参数影响规律和损伤机理对于新型抗冲击仿珍珠母复合材料与结构的设计具有参考价值和指导意义。