FATIGUE STRENGTH OF NON-LOAD-CARRYING TYPE CRUCIFORM FILLET WELDED JOINT WITH UIT IN CASE OF FAILING FROM WELD ROOT

Abstract

 The fatigue failure origin of non-load-carrying type cruciform fillet welded joint is usually a weld toe. However, when UIT (Ultrasonic Impact Treatment) is applied to the weld toe, weld root also become fatigue failure origin. Fatigue crack initiation and propagation behavior and fatigue life in case of root failure have not been sufficiently made clear yet. In this study, fatigue tests on non-load-carrying type cruciform fillet welded joint treated by UIT have been carried out, and the crack initiation and propagation behavior from the weld root have been indicated. In addition, the fatigue life in case of root failure was tried to be estimated by using effective notch stress conception and crack opening-closing behavior.