Experimental and numerical analysis of joints and thin-walled steel beams fabricated through resistance spot welding and hot-dip galvanizing

Abstract

The study conducted a numerical and experimental analysis of lap joints and thin-walled beams made of DC01 steel. The beams consisted of webs formed by two flat bars, which were connected to flanges using cold-formed angles through advanced resistance spot welding (RSW) technology. The beams varied in geometry and mass. Load capacity evaluation was performed on the beams using a test stand consisting a testing machine and additional bending tooling. Prior to testing, some of the beams underwent hot-dip galvanization to create a bimetallic structure. The application of hot-dip galvanization resulted in the filling of free spaces between the welded sheets of the beams, leading to increased load-bearing capacity and stiffness in the galvanized beams compared to the non-galvanized ones. The galvanized beams tested during the experimental study exhibited a bending load capacity that was 59–83 % higher than that of the non-galvanized beams. The RSW lap joints were subjected to a uniaxial tensile test using digital image correlation and tracking (DIC). Three variants of joints were analyzed, differing in the number and arrangement of welds. The results obtained from the experimental tests were then compared with those from numerical analyses conducted in the ADINA software, utilizing the Finite Element Method (FEM). The initiation of cracks in the lap joints occured at the location of maximum plastic deformation, determined experimentally and confirmed by numerical simulations. The strength of the joint was influenced by the number and arrangement of welds in the joint. The use of 3D solid models to analyze RSW lap joints and resistance welded beams allowed for more accurate results in the weld area. The paper also presented the possibilities of using the designed beams.