陶瓷材料预压应力加工的力学模型  

Mechanics Model for Ceramic Materials Machining under Compressive Pre-stress

作　　者：姜胜强[1] 谭援强[1] 张高峰[1] 杨冬民[1] 冯剑军[1] 

机构地区：[1]湘潭大学机械工程学院,湖南湘潭411105

出　　处：《硅酸盐学报》2013年第6期738-744,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51275436;51005194);湘潭大学博士启动基金(12QDZ22)资助项目

摘　　要：基于弹性力学和压痕断裂力学,建立了陶瓷材料预压应力下的加工力学模型,分析了预压应力及载荷比对材料内部第一主应力及最大剪应力的影响。随着预压应力的增大,第一主应力由拉应力逐步转变为压应力,最大剪应力先减小而后随之增大。若施加合适的预压应力,则能降低材料内部的最大剪应力,改变材料内部裂纹的扩展方向,从而有效降低陶瓷加工过程中的损伤。随着载荷比增大,第一主应力在压头后方迅速变为拉应力,最大剪应力也随之增大,但压头正下方的应力状态不受载荷比的影响。最后对碳化硅陶瓷进行预压应力划痕实验,验证了上述分析结果,进一步表明陶瓷材料预压应力加工是可行的。Based on the elastic mechanics and indentation fracture mechanics, a processing mechanics model of ceramic materials was proposed. The effects of pre-stress and load ratio on the first principal stress and maximum shear stress of the material were ana- lyzed. As the compressive pre-stress increases, the first principal stress will transform gradually from tensile stress state to compres- sive stress state, the maximum shear stress first decreases and then increases. If an appropriate compressiive pre-stress is applied, the maximum shear stress within the material is reduced, and the crack propagation direction within materials is changed, leading to the effective reduction of the material damages during processing. The first principal stress behind the indenter changes into a tensile stress, the maximum shear stress increases, but the load ratio does not affect the stress field below the indenter with increasing the load ratio. In addition, the theoretical results by modeling were confirmed by the experimental data of the pre-stress scratching tests on SiC ceramic, indicating that the pre-stress machining of ceramic materials could be feasible.

关 键 词：陶瓷 预压应力加工 力学模型 应力场 

分 类 号：TB301[一般工业技术—材料科学与工程]