(1. 中南大学 机电工程学院，长沙 410083；
2. 深海矿产资源开发利用技术国家重点实验室，长沙 410012)
摘 要: 深海矿物分布在几百米到几千米深的高静水压力环境中，矿物周围的高静水压力可能会显著影响其切割特性。为了研究高静水压下海底多金属硫化物(SMS)的破碎特性及其力学性能对破碎过程的影响，建立了高围压条件下截齿切割SMS的模型。采用了一种力链围压模拟静水围压的作用，围压能适应试样切削过程中的不规则边界并在切割过程中进行更新。在此基础上，分析了试样切削过程中裂纹演化过程、应力分布特征和载荷变化规律。结果表明：围压对切削过程有显著影响，随着围压的增加，刀具载荷线性增加，载荷波动减小，裂纹扩展受到抑制。同时，在高围压条件下，刀具的前刀面上产生条状切屑，表明其破坏模式由脆性模式向延性模式转变。
关键字: 围压；切削机理；离散元；多金属硫化物；力链
（1.School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory of Deep Sea Mineral Resources Development and Utilization Technology, Changsha 410012, China）
Abstract:Deep-sea minerals are distributed in a high hydrostatic pressure environment with hundreds to thousands of meters deep, and the high hydrostatic pressure around minerals may significantly influence their cutting characteristics. In order to study the fragmentation characteristics of cutting seafloor massive sulfides (SMS) under high hydrostatic pressure and how its mechanical properties influence the fragmentation process, a model for cutting SMS with a pick under high confining pressure was established. In this paper, a force chain method was used to simulate confining pressure, which could adapt to the irregular boundary of the sample and update in the cutting process. On this basis, the crack evolution process, stress distribution characteristics and load variation law were analyzed. The results show that the confining pressure significantly affects the cutting process. With the increase of confining pressure, the tool load increases linearly, the load fluctuation decreases, and the crack propagation is restrained. Meanwhile, under high confining pressure, the strip chips are generated on the rake face, which indicates that the failure mode of seafloor massive sulfide transfers from brittle mode to ductile mode.
Key words: confining pressure; cutting mechanism; discrete element method; SMS; force chain
