Buckling Analysis on Cylindrical Shell with Longitudinal and Circumferential Welds

Near to a century, buckling on shells especially on cylindrical shells under axial compression is Bing survey. Buckling of shells carried out less than classical load and many years it was a puzzle for mechanical scientists and researchers. Exactly estimate of buckling critical load for optimum design and safety in mechanical structures like as pressure vessel, rockets, airplane body is very important because buckling is catastrophic. Imperfections consist of geometric defects, variation in thickness, material properties uniformity and boundary condition can be decrease buckling critical load. Geometric imperfections like as out of roundness and ovality is the result of manufacturing process. Plate roll forming and welding is a method for shell fabrication and unavoidable and welds are source of imperfections. Three cylindrical shells fabricated by roll forming and welding. Imperfections of shells measured by 3D scan camera and then tested under axial compression with press. Results show welds have created imperfections especially around the weld line and decrease critical buckling load. Shell with circumferential weld buckled lower than buckling load of shells with only longitudinal weld line. Measured imperfections introduce to nodes in finite element mesh modeling directly and results of finite element analysis compared to experimental load – displacement curves until the effects of welds on critical load compare to perfect shell buckling load.