Fatigue failure is one of the main forms of mechanical structure failure. The development process of local and permanent structural changes in materials that bear disturbance stress at a certain point or some points and form cracks or complete fracture after enough cyclic disturbance is called fatigue. Fatigue life refers to the number or time of cyclic load applied by structure or machinery until failure.
Hydraulic excavator is widely used in earthwork engineering, and it is an essential machinery in engineering construction. The bucket handle of hydraulic excavator is a welded box structure, which often has fatigue cracks, and most of the fatigue cracks are concentrated in the welded joint between the bucket handle and the boom. The main methods for fatigue life assessment of welded structures are nominal stress method, local stress-strain method, equivalent structural stress method and fracture mechanics method.
