Influence of Die Geometry on Electromagnetic Riveting of Ti-6Al-4V: An Explicit Finite Element Analysis

Electromagnetic riveting (EMR) is a high-speed solid-state joining technique with growing relevance in aerospace manufacturing, particularly for titanium alloys such as Ti-6Al-4V. Although the mechanical behavior of EMR joints has been previously studied, the specific influence of die geometry on rivet deformation and joint integrity remains insufficiently understood. In this work, an explicit finite element analysis was conducted using ANSYS Explicit Dynamics to assess the effect of three die geometries (90°, 70°, and 45°) on the mechanical and thermal response of Ti-6Al-4V rivets and plates. The Johnson–Cook constitutive model was employed to capture high strain-rate deformation behavior. Key process metrics, including radial expansion, Von Mises stress, plastic work, and adiabatic temperature rise, were analyzed for each configuration. The results show that sharper die angles (90°) promote greater rivet expansion but also induce higher stress concentrations in the plates, while shallower dies (45°) produce smoother stress distributions with reduced deformation. All configurations demonstrated significant adiabatic temperature rise (approximately 250 °C) in the high-deformation zones. This indicates that thermal softening contributes to the material flow, although the process remains below the phase transformation temperature of Ti-6Al-4V. Overall, the findings highlight that die geometry critically affects stress localization and rivet interlocking, providing guidance for optimizing EMR tooling design to enhance reliability in high-performance aerospace structures.