Wrinkling control in metal spinning through edge geometry and pre-straining: experiments and finite element simulation

Abstract

This thesis investigates flange wrinkling during the first pass of conventional metal spinning and evaluates edge preforming as a practical way to improve stability without changing the final forming objective. The work combines controlled experiments with three-dimensional explicit finite element simulations and uses consistent geometric and mechanical measurements to connect process design, prestrain, and wrinkling response. A main outcome is the quantitative evidence that introducing a preformed flange before spinning can suppress the circumferential buckling modes that develop in flat blanks. Under identical spinning conditions, the flat configuration exhibits pronounced wrinkles, while the flanged edge configuration remains smooth and stable. Wrinkle severity is evaluated from three-dimensional scan data using a peak to valley amplitude measure around the rim, enabling direct comparison across conditions. The results also show that the benefit of the flange depends on the selected flange geometry, particularly the flange angle and flange length, since these parameters govern the added edge rigidity. To explain how edge preforming improves wrinkling resistance, the thesis reconstructs prestrain patterns using microhardness mapping and links these patterns to the evolving stiffness field near the flange root. Calibrated hardness-based relationships and structured sampling across the rim and curvature region are used for AA5052-O. Both edge forming by bending and edge forming by spinning increase hardening near the outer flange, while edge forming by spinning produces a stronger and wider hardened region than bending. These spatial differences support compact scalar measures of prehardening in the curvature band to compare preforming conditions. A supporting numerical assessment shows that moderate simulation acceleration can preserve defect relevant predictions, whereas aggressive acceleration increases inertial influence and reduces reliability. Overall, the thesis provides experimentally anchored guidance for designing edge conditioned blanks and for interpreting stability in spinning through combined geometry, hardness, and stress and strain history evidence.

Date	10 Jun 2026
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Henri Champliaud (Supervisor) & Zhaoheng Liu (Co-supervisor)