Alan J. Gillard

Incremental Forming for Aluminum Automotive Technology

Insufficient formability can be a major issue in the manufacturing of complex parts, particularly in aluminum alloys that have less formability when compared to steel. The approach which is the subject of this work is to determine the technical feasibility of partial forming, followed by a fast heat treatment and then further deformation. Alloys for consideration would include both 5xxx and 6xxx alloys typically used on interior and exterior automotive panels. The heat treatment regimes used for 6xxx alloys did not affect the material structure, which was confirmed by microstructural analysis and comparison of mechanical properties before and after the heat treatment. Experiments on 5xxx alloys indicated relative improvement of 300% or more. Regimes of material deformation and heat treatment will be presented.Copyright

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.