Quality and surface integrity of waterjet machined automotive composites

摘要

Machining edge quality and static, dynamic loading response of two commonly used automotive composites namely sheet mold compound (SMC) material systems - SMC-R27, and SMC-R37 were investigated. In addition to characterizing the fatigue life and low velocity impact response, failure progression of the material systems, the edge effects of diamond saw cutting, waterjet cutting and abrasive waterjet cutting were investigated using optical microscopy and contact surface profilometry. Effects of edge finishing on fatigue life in terms of applied maximum stress to number of cycles to failure. Impact force-time and displacement-time responses were measured and used to characterize energy absorption capabilities and potential correlation to post processing operation and fiber volume fraction. Pre and post-fracture edge surface micrographs were examined to relate the failure behavior on the machined surfaces. Experiments and measurements all show that the failure zone size and fracture growth behavior are clearly dependent on the edge finishing process.