FRACTURE MECHANICS INVESTIGATION OF GRINDING OF CERAMICS

RECENT ADVANCES IN CONTACT FRACTURE MECHANICS HAVE CREATED AN OPPORTUNITY TO APPLY CONTACT FRACTURE MECHANICS TO INVESTIGATE MECHANISMS OF MATERIAL REMOVAL AND DAMAGE PENETRATION DURING ABRASIVE MACHINING OF CERAMICS. IN PHASE I IT IS PLANNED TO EMPHASIZE INVESTIGATION OF THE MECHANISMS OF MATERIAL REMOVAL INCLUDING CRUSHING BY MIXED MODE FRACTURE AHEAD OF THE DIAMOND POINT AND CHIPPING AT LATERAL CRACKS PROPAGATING IN RESPONSE TO RESIDUAL STRESSES INDUCED BY ELASTIC RELAXATION AGAINST THE IRREVERSIBLY DEFORMED ZONE ON UNLOADING. THE OBJECTIVE IS TO DETERMINE THE RELATIVE IMPORTANCE OF CRUSHING AHEAD OF THE DIAMOND POINT AND CHIPPING ALONGSIDE THE TRACK AS A RESULT OF LATERAL CRACKING, FOR VARIOUS MATERIAL PROPERTIES AND GRINDING CONDITIONS. THE ROLE OF CRUSHING IN REDUCING THE RESIDUAL STRESSES THAT ARE RESPONSIBLE FOR LATERAL CRACKING WILL BE INVESTIGATED. MATHEMATICAL MODELS WILL BE DEVELOPEDBY ADAPTING AVAILABLE MODELS FOR STATIC INDENTATIONS. THE EXPERIMENTAL RESULTS WILL BE COMPARED WITH RESULTS PREDICTEDBY THESE MODELS.