Fatigue Quality Index by Infrared Stress Measurement in spot weldment

摘要

Since the spot welding process was completed in a very short time and there were many factors affecting the generation of welding defects, it was difficult to control all experimental factors of welding. Additionally, it was hard to monitor the distribution of stress in practical cases such as vehicle bodies. The purpose of this study was to investigate the applicability of infrared thermography for the evaluation of spot weldability in the view of fatigue life. In this research, infrared(IR) stress analysis adopting an infrared thermography as nondestructive evaluation of spot weldability was investigated. Using temperature and IR stress distribution obtained by an infrared camera from adiabatic heat expansion under a repeated load of sinusoidal waves, we estimated the fatigue quality index(FQI) of spot welded specimens. We also evaluated in terms of FQI and corrected the S-N curve from the original fatigue life curve of base metals.