Fatigue analysis of hybrid steel construction parts using LPBF on hot-rolled steel

Metal additive manufacturing presents significant opportunities in the construction industry by enabling the creation of innovative components and seamless integration with conventional steel parts to form hybrid structures. However, ensuring the long-term performance of such structures, particularly under cyclic loading, requires a comprehensive investigation into the behavior of individual materials and their interfaces. Unfortunately, current European fatigue design standards do not adequately address the unique considerations of metal additive manufacturing. This paper provides a thorough analysis of high-cycle fatigue in butt-joint connections of arc-welded hybrid additive manufactured joints. The study specifically concentrates on the use of arc welding to join an AISI316L plate produced through the Laser Powder Bed Fusion (LPBF) technique with a quarto plate. Experimental tests incorporate engineering stress control and utilize three distinct stress steps to establish S–N curves. The findings highlight the substantial influence of internal defects and their geometric characteristics on stress concentrations and fatigue life. These insights provide valuable understanding regarding the fatigue performance of hybrid additive manufactured joints compared to conventional steel, opening avenues for further research on the integration of metal additive manufacturing components with traditional steel structures.