Numerical analysis of the metal spinning process utilizing rotating reference frames

Abstract

The metal spinning process, a metalworking technique, fabricates axisymmetric shaped products from circular workpieces by leveraging the plastic deformation properties of certain metals. Despite its widespread use, significant gaps persist in our understanding of this process as revealed by existing literature. Key areas requiring further investigation include: the incomplete characterization of stress and strain evolution beyond the elastic domain; a limited understanding of failure mechanisms such as cracking and wrinkling; and the lack of reliable methods for designing toolpaths to produce final parts without defects. This thesis addresses these gaps by implementing a numerical model configured within a rotating reference frame, resulting in a substantial reduction in computational time by a factor of 50 while improving accuracy. Furthermore, the integration of the Generalized Incremental Stress State dependent damage Model within this rotating reference frame configuration enhances the prediction of circumferential cracking efficiency. A novel approach is proposed for analyzing the process throughout one full rotation of the mandrel, as opposed to solely at the end of the process, which has been validated against existing literature. This analysis exhibits that the flange radius diminishes with each plastic deformation induced by the roller, leading to the development of wrinkles on the flange. Two specific parameters, namely the amplitude and the number of peaks, are employed to characterize the flange wrinkling shape, revealing an inverse relationship between them due to volume consistency. Notably, the appearance of new peaks continuously during the process is observed. Intermediate paths with appropriate stroke angles are identified as effective means to control wrinkle amplitude safely by increasing the number of peaks. Additionally, these intermediate paths mitigate thinning issues in the final product. The process can be more flexible, to produce a wider range of shapes, and to form more challenging materials.

Date	17 Jul 2024
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Henri Champliaud (Supervisor) & Van Ngan Lê (Co-supervisor)