MODELING THE SUBSURFACE DAMAGE ASSOCIATED WITH THE MACHINING OF A PARTICLE-REINFORCED MMC

The sub-surface damage resulting from the machining of a particle rein forced MMC, with various cutting tool geometries, was simulated using the finite element method. A sub modeling technique was used in order to analyze the micro-mechanical behavior of the material. The metal cu tting model was a fully coupled thermo-mechanical simulation, while th e micro-mechanical behavior of the ceramic/matrix interface was a pure ly mechanical simulation. The metal cutting simulation assumes the mat erial to behave as an viscoplastic material while the micro-mechanical model assumes the SiC to behave elastically while the matrix material behaves elasto-plastically. The results obtained from the FEA were co mpared with chip root samples obtained under similar conditions. The e ffect of machining with an excessively worn tool was also examined. In terfacial debonding was simulated through the use of coupled equations which couple interfacial nodal degrees of freedom until otherwise spe cified. As a result of the current FE simulation's it was found that a pproximately 8.1% of the interfacial nodes became debonded as a result of the turning operation, compared with approximately 32.2% for the w orn positive rake angle cutting tool simulation. (C) 1997 Elsevier Sci ence B.V.