Photoelastic Analysis of Thermal Stress in Laser Lap Welding of Thermoplastic Plates (2nd Report, The Influence of Residual Stress on Welding Strength)

摘要

In 1st report, thermal stress and residual stress in a transparent polycarbonate plate under the process of laser wrap welding were analyzed by photoelastic method. In this 2nd report, the relation between residual stress and photoelastic stripes and that between photoelastic stripes and welding strength are discussed. It is proved that large thermal stress provokes dense photoelastic stripes and results in strong welding strength. It is considered that residual stresses have a great influence on welding strength, probably because there are residual stresses that cancel a load