The effect of an electromagnetic peening process on mumetal properties
Peening processes are widely used in the industries to enhance the performance of the most solicited parts of mechanical pieces. Actual processes, like shot peening and low plasticity burnishing, are quite limited to a small depth of treatment circa 1 mm at maximum. A new process is developed based on pulsed electromagnetic fields. This method allows a better depth of treatment up to 5 mm and it can be easily monitored. A prototype was developed using a pulse current generator and specifically designed inductor. This prototype was used on mumetal for the preliminary tests. Indeed, its maximal permeability and coercivity are highly impacted by the presence of stresses. Using specifics sensors, some changes occur after treatment on mumetal samples and can be observed.
Numerical simulation of electromagnetic surface treatment
Surface treatment methods, such as shot peening or laser shock peening, are generally used to introduce superficial compressive residual stresses in mechanical parts. These processes are carried out during the manufacturing steps or for the purpose of repairing. The compressive residual stresses prevent the initiation and growth of cracks and thus improve the fatigue life of mechanical components. Electromagnetic pulse peening (EMP) is an innovative process that could be used to introduce compressive residual stresses in conductive materials. It acts by generating a high transient electromagnetic field near the working surface. In this paper, the EMP process is presented and a sequentially coupled electromagnetic and mechanical model is developed for its simulation. This 2D axisymmetric model is set up with the commercial finite element software SYSWELD. After description and validation, the numerical model is used to simulate a case of introducing residual stresses of compression in a nickel-based alloy ...
Comparison of two different simulation algorithms for the electromagnetic tube compression
Simulation tools especially for the electromagnetic forming process (EMF process) offer the opportunity to analyse the formation process and its effects already in the development stage. The EMF process is a high-dynamic process with high transformation velocities. The deformation results from the interaction of the electrical current in the forming coil and the induced eddy current in the workpiece, represented by the Lorentz force. Most of the simulation tools and models for the EMF process are limited to small deformations. The connection between electromagnetic field and spatiotemporal evolution of the deformation of the workpiece is not negligible for example for working out a door handle recess in the automotive industry. This paper presents a comparison of a custom loose-coupled simulation model and a more accurate sequential-coupled approach. The deviations between the two simulation models increase with time, so that the loose-coupled approach leads to an overestimation of the final deformation. The correspondence of the sequential-coupled simulation with the measurement result is much better than for the loose-coupled simulation.