脆性材料在准静态和冲击压缩载荷作用下的动态碎裂过程

We propose to study experimentally the compressive failure and dynamic fragmentation of typical brittle materials under quasistatic or impact compressive loadings. The selected materials can include ceramics, concretes, and rocks. In each test the compressive fragmentation phenomenon of the material will be observed, and the fragments of the specimen after its failure will be collected for statistical investigations. Subsequent analysis will be carried out to explain the mechanisms of failure and fragmentation of brittle materials under compressive loading. Numerical simulations will be conducted to reveal the fragmentation process. We endeavor to establish a relationship to link the brittle material's mechanical properties (strength, ductility, density, modulus, etc) and the loading conditions (loading rate, stress components), to its fragmentation properties (fragment size and size distributions). An engineering models will be worked out that could be used to evaluate the material's mechanical properties through its fragmentation behaviors. The proposed research will increase people's understanding of the failure and fragmentation properties of brittle materials. The investigation may also help to explain the complex compressive failure properties of brittle materials such as projectile break-up under impact, underground rock explosions during tunneling, and failure wave propagations.

实验研究以陶瓷、混凝土、岩石等材料为代表的脆性材料在准静态和冲击压缩载荷作用下的破坏过程和强度特性，观察典型材料的压缩动态破碎现象，获得材料压缩破坏后产生的碎片的宏观统计规律。分析实验现象，解释脆性材料的冲击压缩破坏及动态破碎机理，并通过数值模拟方法再现材料的压缩碎裂过程。致力于建立材料强度、韧性、密度、弹性模量等力学参数以及受载荷情况（加载率、加载形式）与其破碎特性（碎片尺度及分布）之间的联系，提出工程实用的材料压缩破碎模型，寻找可能的通过破碎特性反映脆性材料综合抗冲击指标的方法。研究成果将有助于加深人们对脆性材料高应变率压缩破坏过程的理解，也可以为解释包括高速弹体的冲击压缩碎裂、地下挖掘过程中遭遇的岩石爆炸、冲击波阵面后方的破坏波传播等复杂现象提供新见解。

总结前期研究成果，提出材料动态碎裂的最快速卸载理论，给出脆性材料的碎片尺度公式；开展了陶瓷、混凝土、玻璃等脆性材料在准静态和冲击压缩载荷作用下的实验研究，观察材料的动态压缩破碎现象，获得陶瓷材料压缩破坏后产生碎片的宏观统计规律；与理论模型进行对比，证实了所提出的碎片尺寸模型的有效性；分析研究了脆性陶瓷材料在准静态和高应变率压缩过程中的强度、以及破碎现象；采用离散颗粒动力学方法模拟再现了材料的压缩碎裂过程。试制了高速气枪装置，开展了脆性玻璃圆杆的Taylor撞击试验研究，观察和分析了玻璃材料中的破碎波（阵面）传播现象。开展了脆性高分子材料的动态断裂研究，首次观察到接近或超Rayleigh波速I型裂纹的动态传播现象；采用新开发的膨胀环实验装置成功开展了脆性高分子材料的冲击拉伸碎裂实验研究。