A large number of factors is involved in determining the welded joints fatigue strength, but it is very difficult to consider their relative importance. In this general perspective, the explicit aim of this paper is to try to isolate as possible the effect of the residual stress by the other factors in order to establish a relation, which lies the amount of the residual stress in a welded joint to the fatigue life. In order to achieve this result, the geometrical notch due to the weld cord is removed by milling the upper surface of the welded plates. Moreover, the specimens are subjected to a four-point bend loading. Before the execution of the fatigue test the magnitude of the residual stress for each specimen is experimentally evaluated and then linked to the number of cycles to failure. This relation is looked for three different plate thicknesses (variable from 8 to 20 mm) and for different stress amplitude levels in the high cycle regime. The results clearly show a significative influence of the residual stress on the fatigue behaviour when the load level is near the fatigue limit.
On the residual stress and the fatigue resistance of butt-welded joints
DATTOMA, Vito;DE GIORGI, Marta;NOBILE, RICCARDO
2004-01-01
Abstract
A large number of factors is involved in determining the welded joints fatigue strength, but it is very difficult to consider their relative importance. In this general perspective, the explicit aim of this paper is to try to isolate as possible the effect of the residual stress by the other factors in order to establish a relation, which lies the amount of the residual stress in a welded joint to the fatigue life. In order to achieve this result, the geometrical notch due to the weld cord is removed by milling the upper surface of the welded plates. Moreover, the specimens are subjected to a four-point bend loading. Before the execution of the fatigue test the magnitude of the residual stress for each specimen is experimentally evaluated and then linked to the number of cycles to failure. This relation is looked for three different plate thicknesses (variable from 8 to 20 mm) and for different stress amplitude levels in the high cycle regime. The results clearly show a significative influence of the residual stress on the fatigue behaviour when the load level is near the fatigue limit.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
