Study on the preparation and mechanical properties of resistance‐welded glass fiber/polypropylene cylindrical shell structures

Abstract When thermoplastic composite cylindrical shell structures are applied to large‐scale structures, their connection issues remain a challenge in engineering. Particularly, the mechanical properties and structural stability of the welding areas of cylindrical shells under external forces are critical considerations in the design and manufacturing process. This paper prepared glass fiber/polypropylene (GFPP) complete cylindrical shell structures (CCS) and GFPP resistance‐welded cylindrical shell structures (RWCSS) using vacuum hot‐pressing technology and resistance welding processes. Through radial and axial compression tests, it was found that under radial compression conditions, RWCSS had an average peak load 81.50 N (14.90%) lower than CCS, Meanwhile, its initial stiffness and average crushing force increased by 3.06 N/mm (60%) and 62.46 N (22.62%) respectively. After initial radial compression, CCS was more likely to experience buckling deformation and tearing along the cracks when subjected to axial compression. In contrast, RWCSS mainly exhibited folding deformation along the connection interface, accompanied by local fiber and matrix cracking. Low‐velocity impact tests using a drop‐weight impact test indicated that the damage to RWCSS was primarily at the edges of the connection area and the fibers and matrix of the upper and lower cylindrical shells. Highlights Compared with CCS, the initial stiffness and average crushing force of RWCSS under radial compression increased by 60% and 22.62% respectively. The average peak displacement of RWCSS after radial compression under axial compression is twice that of CCS. Low‐velocity impact tests reveal damage in RWCSS is primarily at connection edges.