Computational Methodology for the Development of Wrinkled Tubes by Plastic Deformation

Abstract

Traditional methods for wrinkled tubes involve welding processes and additional elements, such as plates, screws, rivets, and guides. Considering all the limitations of these processes, this work aims to propose a methodology that allows for maximising the manufacturing process of carbon steel tube joints with seaming using cold forming and minimising the cost of the final product. Therefore, the present work aims to develop a computational model, based on the finite element method, to optimise the deformation process of T6 Aluminium tubes (ø 45 × ø 38.6 mm) with a length of 120 mm. The method uses a steel die with cavities to achieve wrinkled tubes by a forming process. This numerical study was carried out using the Ansys® 2022 R2 software. A nonlinear material and an incremental structural analysis were used. The applied methodology allowed the optimisation of process parameters, the application of forces during tube deformation, the geometry of the die cavity, boundary conditions, and mesh discretisation. Numerical modelling was carried out using the axial symmetry of the assembly (tube–die), enabling a simplified and efficient execution of the final tube geometry. The results were analysed based on the maximum pressure applied to the tube, and the vertical and horizontal displacements of the deformed component, thus obtaining the tube flow with complete filling inside the die cavity at the end of deformation. The die geometry that produced the best results presented a cavity with a radius of curvature of 3 mm, 6 mm in height, and with a depth of 4 mm. The optimised result of the die geometry generated satisfactory results, with the displacement on the x-axis of the tube of approximately 2.85 mm, ensuring the filling of the cavity at the end of the process. For this, the maximum pressure exerted on the tube was approximately 374 MPa.

Keywords

• wrinkled tube
• tube-die assembly
• mechanical forming
• numerical model