Fatigue life evaluation of web butt welding structure on boom of excavator by hot spot stress approach

The working load of excavator is complex and the working environment is bad. As the main part of excavator, the boom bears a large complex load and is prone to fatigue damage. A large hydraulic excavating boom is taken as the research object in this paper, aiming at the damaged position in the platform fatigue test, that is, the web butt weld on the root of the boom, and the fatigue life of this part is evaluated by means of hot spot stress and load spectrum. The result shows that the theoretical lifetime of this part is 4148 h, which is completely agree with the equivalent life 4278 h when the cracks appeared in bench fatigue tests. Accordingly, the hot spot stress approach is suitable for the fatigue life evaluation of the boom, and its accuracy is high.