中文摘要：

通过微结构设计提升脆性功能材料的冲击塑性,将有助于避免或延缓失效的发生.提出在脆性材料中植入特定的微小孔洞以改善其冲击塑性的设计方法.采用一种能够定量表现脆性材料力学性质的格点-弹簧模型、研究了孔洞排布方式对脆性材料冲击响应的影响.孔洞随机排布的多孔脆性材料具有明显高于致密脆性材料的冲击塑性,而设计规则的孔洞排布方式将有助于进一步提升脆性材料的冲击塑性.对150 m/s活塞冲击下气孔率5%的多孔样品的介观变形特征分析表明,孔洞规则排布的样品中孔洞贯通和体积收缩变形占主导,而孔洞随机排布的样品中剪切裂纹长距离扩展和滑移与转动变形占主导.尽管在宏观的Hugoniot应力-应变曲线上,两种孔洞排布方式的样品都表现出三段式响应特征（线弹性阶段、塌缩变形阶段和滑移与转动变形阶段）,但孔洞规则排布时孔洞塌缩变形阶段对整体冲击塑性的贡献更大.研究揭示的规则排布孔洞增强脆性材料冲击塑性的原理,将有助于脆性材料冲击诱导功能失效的预防.

英文摘要：

The mechanical properties of a material are closely related to its internal micro-structure.Enhancing shock plasticity by designing appropriate micro-structure will help to slow down or delay shock failure of brittle material.In this paper,we put forward a method of designing and improving shock plasticity of brittle material by implanting specific microvoids.A lattice-spring model is adopted,which can represent mechanical properties of brittle materials quantitatively.Simulations reveal how the arrangement modes of micro-voids can affect the shock response of brittle material.By implanting randomly arranged voids,porous brittle material has significantly higher shock plasticity than dense brittle material and the design of the regular arrangement mode of voids will help to enhance the shock plasticity further.The dominant mechanism corresponding to the void collapse in the shocked brittle material is shear slip caused by shear stress concentration,which features the occurrence of shear cracks around the voids.Features of mesoscopic deformation in the sample with 5%porosity indicate that the shock plasticity of porous brittle material comes from the volume shrinkage deformation caused by void collapse and the slippage and rotation deformation caused by extension of shear cracks.The inter-permeation of voids and volume shrinkage deformation play a leading role in the sample with regularly arranged voids.While the shear cracks extends over long distance,slippage and rotation deformation take place dominantly in the sample with randomly arranged voids.The two samples with different arrangement modes of voids both have three stages of response in the Hugoniot stress-strain curves in this paper,i.e.,linear elasticity stage,collapse deformation stage,and slippage and rotation deformation stage.The sample with higher porosity has a higher shock plasticity than the sample with lower porosity.When the samples have the same porosity,the collapse deformation stage makes greater contribution to the overall shock plasticity i