Fatigue Life Estimation on HSLA Chassis Frame

Fatigue tests were performed on five kinds of fillet welded joints on 2.6 mm thick HSLA steel sheets, to evaluate the fatigue life of automotive HSLA chassy frame with different joint geometries under various loading conditions. Specimens were made by CO₂ gas arc welding with 1.2 mm diameter wire. During the fatigue tests at stress ratio (R)=−1, dynamic strain was measured using a 3 mm strain gage cemented on the sheet surface nearest to the toe. Data were discussed by nominal stress as well as by local strain.