Numerical Simulation Study on the Holding Force and Pull-out Strength of Surface-Set Diamond Core Bits

To investigate the gripping force characteristics of surface-mounted single-grain diamonds and their detachment behavior under complex loading conditions, this study combines finite element numerical simulation and experimental verification to establish a three-dimensional mechanical model of the “metal matrix–interface–diamond” system. The distribution and evolution of the gripping force under the coupled effects of multiple factors, including diamond particle shape, size, exposure height, and inclination angle, are systematically analyzed. The results indicate that: (1) The topological structure of regular polyhedral abrasive particles determines their interfacial retention performance. Specifically, the dodecahedron exhibits the highest bonding strength, while the hexahedron shows the best energy absorption capacity. (2) Reducing the exposure height of abrasive particles significantly enhances both the interfacial retention force and toughness, which is a key factor in optimizing retention performance. (3) The interfacial retention performance is positively correlated with diamond particle size; larger particles can synergistically improve both the strength and toughness of the tool interface. (4) Inclined implantation of diamond particles can effectively regulate retention performance: a 45°inclination corresponds to the highest tensile strength, while a 30°inclination provides the best impact toughness.