This paper presents a method to evaluate the ultimate strength and fracture mechanism of inclined fillet welds under different loading angle. The proposed mechanical model consists of two rigid parts of the fillet welds separated by a fracture plane, and the ultimate strength and the fracture mechanism of this model are derived by means of the upper bound theory. Based on the theoretical solutions, a simple design formula is presented. Its accuracy is verified by the results obtained from loading tests conducted in this study.
