Numerical and experimental optimization of welded stainless-steel liners for lightweight road tanks

Abstract

The aim of this work is to reduce the weight of road tanks by decreasing the thickness of the metal sheets and optimizing the welding processes used in their assembly. In order to achieve this objective, the approach is to reinforce the mechanically welded stainless-steel liner with a fiber-resin composite filament winding, which will be investigated in future work. Thus, the thickness of the tank's liner was reduced from 3 mm to 1 mm, resulting in a mass reduction of 500 and 1000 kg per tank. This corresponds to a potential increase in the mass of fluid that can be transported and also leads to lower fuel consumption and CO₂ emissions per ton of transported fluid. Importantly, all these benefits were achieved without compromising structural rigidity or durability. The liner was manufactured using a combination of Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW) in Cold Metal Transfer (CMT) mode. Three-dimensional scanning measurement campaigns were used to record displacements and geometric defects, such as cylindricity, during the construction of a one-quarter-scale cylindrical tank prototype. The collected data were then compared with the welding-induced distortions calculated by an optimized numerical model designed to provide a reliable response with reduced computation time. Consequently, the present model facilitates the prediction of mechanical strains and stresses while reducing computational time by almost a factor of 10 compared to conventional transient thermo-mechanical simulations.