Abstract Functionally graded brittle materials will inevitably produce defects such as micropores in the preparation process, which will significantly affect its impact response. Understanding its mesoscopic evolution mechanism and macro-response law will make micropores favorable for the engineering application of functionally graded brittle materials. By establishing a lattice-spring model that can accurately represent the elastic properties and fracture evolution of materials, this paper reveals the influence of pore evolution on functionally graded brittle materials. Collapse deformation caused by impacted holes and slip deformation caused by shear cracks emitted from holes produce significant stress relaxation and modulate the propagation of shock waves. In porous functionally graded brittle materials, shock waves are gradually broadened into elastic waves and deformation waves. The deformation wave is macroscopically similar to the plastic wave of ductile metal material, and corresponds to the collapse deformation and slip deformation process on the micro-level. Porosity in the sample determines the elastic limit of functionally graded brittle materials. Porosity, material parameters, and impact velocity jointly affect the propagation speed of the deformation wave and the stress amplitude in the final state of impact. Functionally graded brittle materials with micropores have potential application value in shock wave complex loading experiments, failure prevention of functional materials, building protection, etc. The obtained impact response laws are helpful to optimize the design of impact response and dynamic mechanical properties of functionally graded brittle materials for specific applications.

中文翻译：

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具有孔洞损伤的功能梯度脆性材料冲击响应特性及细观演化机制

摘要 功能梯度脆性材料在制备过程中不可避免地会产生微孔等缺陷，严重影响其冲击响应。了解其细观演化机制和宏观响应规律，将使微孔有利于功能梯度脆性材料的工程应用。本文通过建立能够准确表示材料弹性特性和断裂演化的晶格-弹簧模型，揭示孔隙演化对功能梯度脆性材料的影响。由撞击孔引起的坍塌变形和由孔发出的剪切裂纹引起的滑动变形产生显着的应力松弛并调节冲击波的传播。在多孔功能梯度脆性材料中，冲击波逐渐展宽为弹性波和变形波。变形波宏观上类似于塑性金属材料的塑性波，微观上对应于塌陷变形和滑移变形过程。样品中的孔隙率决定了功能梯度脆性材料的弹性极限。孔隙率、材料参数和冲击速度共同影响变形波的传播速度和冲击最终状态下的应力幅值。具有微孔的功能梯度脆性材料在冲击波复合载荷实验、功能材料失效预防、建筑保护等方面具有潜在的应用价值。