Infrared stress measurements of thermal damage to laser-processed carbon fiber reinforced plastics

Recently, the laser processing of carbon fiber reinforced plastics (CFRPs) has attracted attention owing to the high processing speed and less tool wear. A problem in the laser processing of CFRPs is the lower strength than that of CFRPs processed by machines. This is considered to be due to the heat-affected zone (HAZ) generated during laser processing. In this study, the stress distributions of CFRPs processed by a laser obtained was evaluated by using infrared thermography. X-ray CT images were also obtained, which enabled us to discuss the stress distribution in terms of the HAZ. The stress distribution showed that the area with reduced stress generated in the HAZ which was introduced by laser processing. The region of low stress in the HAZ was visualized by infrared thermography. It is shown that the regions with reduced stress induce the conventionally reported decrease in strength of laser-processed CFRPs.