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The use of lightweight magnesium (Mg) alloy offers significant potential to improve automotive fuel efficiency. However, the application of formed magnesium alloy components in auto-body structures is restricted due to this material's low formability at room temperature and lack of knowledge for processing magnesium alloys at elevated temperature. In this study, non-isothermal finite element (FE) simulation has been conducted for forming round cups and rectangular pans from Mg alloy AZ31B sheet at elevated temperatures. The results were compared with experiments, conducted at the Technical University, Hanover. Simulation and experiments predicted increase in limiting draw ratio (LDR) with increase in temperature. Maximum LDR was obtained at the forming temperature of 200 • C. FE simulation results agreed well with experimental observations.

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The success of a tube hydroforming (THF) process is highly dependent on the loading paths (axial feed versus pressure) used. Finite element (FE)-based simulation was used to determine optimum loading paths for hydroforming of structural parts with different tubular materials. Experimental and simulation results have demonstrated that FE-based loading paths can significantly reduce trial and error, enhance productivity and expand the THF capability in forming complex parts. The test results also demonstrated that the reliability of the FE-based loading paths is highly dependent on the accuracy of the material properties of the blank, interface friction, and how close the properties of the welding zone are to the base material of the tubular blank.

In sheet metal forming operations, springback of the part during unloading largely determines whether the part conforms to the design dimensions and tolerances. Finite element simulations were performed in order to study the interrelationship of the blank dimensions and interface conditions on the springback for an axisymmetric conical part manufactured by flexforming. Sensitivity analysis done using the finite element method (FEM) demonstrated that the magnitude of springback and the overall dimensional quality are highly influenced by the initial dimensions of the blank. A conventional optimization method combined with FEM was used to obtain optimum blank dimensions that can reduce springback.

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The advancement of micro tube hydroforming (THF) technology has been hindered by, among others, the lack of robust microdie systems that could facilitate hydroforming of complex parts that require both expansion and feeding. This paper proposes a new micro-THF die assembly that is based on floating a microdie-assembly in a pressurized chamber. The fluid pressure inside the chamber which surrounds the dies and punches is the same as the pressure required to hydroform the tube. The fluid pressure intensity in the chamber varies in accordance with the predetermined pressure loading path required to successfully hydroform the part. The system was built, and hydroforming experiments were carried out for various micro- and meso-scale shapes, including bulge-shapes, Y-shapes, and T-shapes.

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