高速侵彻岩石的局部破坏机理与实验研究

High velocity penetration into rock is a highly complex process, which mechanism is not well revealed. At present, there is no sophisticated constitutive model and material parameter data base. The accuracy measurements is difficult to achieve in experiments. In order to get deeper insight into the high velocity penetration process, an approach will be engaged which integrates achievements in multi-scale mechanics of fracture and damage of rocks into high velocity impact problems. The main research contents of the project includes: (1) based on the evolution and propagation regularity of brittle crack, investigate the dynamic deformation and failure process of rocks in impact near-field, reveal the damage mechanism and establish similarity law of high-speed penetration; (2) characterize the dynamic damage of rock material based on method of fracture and dissipative damage mechanics, and establish dynamic constitutive equations of rock-like materials under high velocity penetration; (3) improve laboratory test design methodology and comprehensive measurement system, determine key model parameters with quasi-static tests, SHPB tests, light-gas-gun flying plate tests and scaled high velocity penetration tests; (4) finally achieve numerical simulation much more reliable in multiple levels, stages and dimensions. The expected achievements of the project could supply new theories, methodologies and approaches for dynamic behaviors of materials and structures under dynamic loads.

本项目根据目前岩石高速侵彻动态破坏机理不清、数值模拟缺乏完善的本构模型及配套材料数据库缺失、实验研究量测与表征不精细的现状，尝试将现代岩石断裂损伤力学及工程地质在多种尺度下的研究成果与高速撞击问题结合起来，根据脆性裂纹演化规律和扩展准则研究高速侵彻近区的局部变形特征，揭示岩石高速侵彻动态毁伤机理，建立弹体侵彻相似规律，利用断裂力学和散布损伤力学手段研究高速侵彻中材料动态损伤的表征方法，建立高速侵彻下岩石类材料的动态本构关系，发展新型室内科学实验设计方法与综合测试技术，利用准静态压缩实验、SHPB压杆实验、轻气炮飞片实验和高速侵彻缩比实验确定模型中关键参数，利用相似律关系、缩比实验、数值模拟实现侵彻过程中岩石多阶段、多尺度破坏过程的有效分析，为推进强冲击载荷下材料与结构的动态力学行为研究提供新的理论、方法和手段。

本项目以重大防护工程需求为背景，针对高速侵彻下岩石介质的动态力学特性和破坏行为，探索新型室内科学实验与测试技术，开展高压加载实验和高速侵彻缩比实验，建立高速侵彻下岩石类材料的动态本构模型，获得与模型配套的低压至高压全阶段的材料参数，揭示岩石结构的侵彻机理与破坏特征，实现侵彻过程数值模拟，为强冲击载荷下材料与结构的动态力学行为研究提供新的理论、方法和手段。通过项目实施，系统研究了大理岩介质静-动态力学性能，获得了力学性能参数；基于SHPB-DIC实验技术阐明了高应变率下岩石介质动态断裂过程；建立了大理岩介质本构模型，并确定了模型参数；开展了岩石介质飞片撞击实验并建立了物态方程；建立了以二级轻气炮为发射装置的高速侵彻实验平台，开展了宽速域侵彻实验研究，获得了从刚性侵彻至半流体侵彻阶段的典型实验结果；完成了岩石高速侵彻动态毁伤数值模拟，完成了侵彻全过程仿真，并分析了弹体尺寸对侵彻效应的影响；在此基础上，建立了岩石内摩擦扩展摩尔库伦模型、弹靶相互作用模型和弹体侵彻阻力与侵深计算模型，阐明了弹体高速侵彻岩石的局部破坏机理。相关的理论成果与材料模型参数可应用于高速深钻地弹侵彻机理与防护对策研究，以促进我国钻地武器与工程防护技术的进步。