Alexander V. Mamutov

Electrohydraulic Sheet Metal Forming of Aluminum Panels

In this paper, we present results of testing from sheet metal forming trials using pulsed electrohydraulic technology. Pulsed electrohydraulic forming is an electrodynamic process, based upon high-voltage discharge of capacitors between two electrodes positioned in a fluid-filled chamber. Electrohydraulic forming (EHF) combines the advantages of both high-rate deformation and conventional hydroforming; EHF enables a more uniform distribution of strains, widens the formability window, and reduces elastic springback in the final part when compared to traditional sheet metal stamping. This extended formability allows the fabrication of aluminum panels that are difficult to make conventionally even of EDDQ steel, and it thereby vastly improves the number automotive weight reduction opportunities. The paper presents discoveries regarding chamber design, electrode erosion, forming, and results of finite element multiphysics simulations of system performance.

Analysis of Dynamic Loads on the Dies in High Speed Sheet Metal Forming Processes

During high-speed sheet metal forming processes, the speed at which the work piece contacts the die tooling is on the order of hundreds of meters per second. When the impact is concentrated over a small contact area, the resulting contact stress can compromise the structural integrity of the die tooling. Therefore, it is not only important to model the behavior of the workpiece during the high-speed sheet metal forming process, but also important to predict accurately the associated workpiece/tooling interface loads so that engineers can more confidently propose robust die tooling designs. The foundation to accurate predictions of contact stress on die tooling is a reliable contact model within the context of a finite element simulation. In literature, however, there exists no comprehensive guideline for establishing a contact model for high-speed sheet metal forming processes using the finite element method. In this paper, mathematically justified contact model recommendations are offered for the electrohydraulic forming (EHF) process.

Electrohydraulic Forming of Light Weight Automotive Panels

This paper describes the results of development of the electrohydraulic forming (EHF) process as a near-net shape automotive panel manufacturing technology. EHF is an electro-dynamic process based upon high-voltage discharge of capacitors between two electrodes positioned in a fluid-filled chamber. This process is extremely fast, uses lowercost single-sided tooling, and potentially derives significantly increased formability from many sheet metal materials due to the elevated strain rate. Major results obtained during this study include: developing numerical model of the EHF; demonstrating increased formability for high-strength materials and other technical benefits of using EHF; developing the electrode design suitable for high volume production conditions; understanding the limitations on loads on the die in pulsed forming conditions; developing an automated fully computer controlled and robust EHF cell; demonstration of electrohydraulic springback calibration and electrohydraulic trimming of stamped panels; full scale demonstration of a hybrid conventional and EHF forming process for automotive dash panel.