PDC Shock Resistance And Structural Parameters Optimization Research

As a new super-hard composites material products, Polycrystalline Diamond Compacts (PDC) have been widely used in petroleum,geology,coal mining drilling,mechanical processing and many other fields after years of research and extension, achieved more and better economic benefit and social benefit. PDC shock resistance reflecting PDC toughness and bonding strength, is a comprehensive indicator,and determines its using performance. The shock damage mechanism of PCD layer attracts more and more attention by people, making PDC product performance stably and constantly improving links the users'interests together closely, and is the goal all factories wish to achieve.Affecting PDC shock resistance mainly include two aspects:macro structure and microscopic processes. This paper only consider diamond/carbide thickness ratio, PDC diameter-thick ratio, diamond/carbide interface structure and installation angle of PDC as the main structure influencing factors of PDC resistance performance.This paper simulates PDC residual thermal stress with diamond/carbide thickness ratio H, diameter-thick ratio T and typical planar interface using ANSYS Parametric Design Language(APDL). The author gets all kinds of residual thermal stress with different condition, and compares them to optimize PDC structure, then bring up the calculating formula of residual thermal stress in different conditions,providing a composite thread to a reasonable design of PDC.Considering installation angle of PDC bits on the anchor(including cutting angle and the side angle)as optimization factors, The author simulates PDC impact process by ANSYS/LS-DYNA,then gets PDC structural optimization based on shock resistance by comparing PDC First principal stress with different factors.Because cutting load in PDC broken rock process is cyclical, The author analyses PDC and PDC anchor modal and gets their inherent frequency. Comparing with load data in practical use, we can get that PDC won't resonate by rock impact in cutting process.The test uses the method similar to the drop weight method (DWTT) to detect PDC samples impact resistance. The impact hammer falls down from certain height freely by gravity and hits the edge of the PDC,making PDC fatigue damage. When the surface of PDC sample appears visible crack or breaks we stop it, the total Impact times N (or total energy) is the index of PDC impact performance.