Finite Element Analysis of Hot Spot Stress in a Fillet-Welded Joint on the Ship Bottom Structure with Emphasis on Sustainable Safety Infrastructure

Abstract The weld on a ship’s bottom structure plays a crucial role in ensuring the strength and safety of the structure. One critical component is the fillet-welded joint, which may experience stress due to the welding process. This study aims to analyze the effect of fillet weld shape variations (mitre, concave, and convex) on nominal stress and hot spot stress in a stiffened bottom plate using the finite element analysis (FEA). A 3D model was developed, incorporating thermal and structural analyses in finite element simulation software. Heat input variations were calculated based on Shielded Metal Arc Welding (SMAW) parameters, followed by temperature to load conversion for stress analysis. The results indicate that each weld variation produces distinct heat distribution, stress, and deformation patterns. The simulations reveal that each weld model variation yields different temperature, tensile stress, and deformation values. Model A recorded a maximum temperature of 543,25°C, a maximum tensile stress of 80,718 MPa, and a maximum deformation of 0,018 mm. Model B exhibited the highest temperature at 530,29°C, with a maximum tensile stress of 72,247 MPa and a maximum deformation of 0,015 mm. Meanwhile, Model C reached a peak temperature of 569,79°C, a maximum tensile stress of 76,891 MPa, and a maximum deformation of 0,017 mm. Based on these combined results, Model B is the most effective for fillet-welded joint applications due to its relatively low tensile stress and minimal deformation.