Low-Cycle Fatigue of Welded Joints

Environmental temperatures, size effects, welding residual stresses impose challenges in the high- and low-cycle fatigue assessment of welded joints. In comparison to widely acknowledged ENS for the high-cycle fatigue assessment in the previous chapter, the low-cycle fatigue assessment of welded joints requires a uniformly accepted approach that can address the above-mentioned factors. The tedious procedure in building multiple FE models with different crack profiles limit the efficiency in application of the conventional fracture mechanics. Therefore, this chapter summarizes the experimental results for various welded joints under low-cycle fatigue loadings at room and low temperatures as well as proposes energy-based damage framework to uniformly evaluate fatigue life. By incorporating thermal-mechanical analysis, the evolution of the residual stresses of welded joints and their effects on fatigue life can be well numerically captured based on the proposed energy-based damage framework.