Abstract
The aluminium alloy sheet forming processes forging in rubber pad and diaphragm presses (also known as hydroforming processes) are simple and economical processes adapted to aeronautical production. Typical defects of these processes are elastic recovery, necking, and wrinkling, and they present difficulties in control mainly due to property variations of the sheet material that take place during the process. In order to make these processes robust and unresponsive to material variations, a multiobjective optimization methodology based on the Taguchi method is proposed in the present study. The design of experiments and process simulation are combined in the methodology, using the nonlinear finite element method. The properties of sheet material are considered noise factors of the hydroforming process, the objective being to find a combination of the control factors that causes minimal defects to noise factors. The methodology was applied to an AA2024-T3 aluminium alloy sheet of 1 mm thickness stamping process in a diaphragm press. The results allowed us to establish the optimal pressure values, friction coefficient between sheet and block, and friction coefficient between sheet and rubber to reduce the elastic recovery variations and the minimal thickness before noise facts.
Highlights
IntroductionThe contour flaps are folded into sheet pieces from 0.5 to 3 mm, with a flat core, generally belonging to ribs or to aeronautical structural elements
A total of 16 trials were performed using Finite Elements Method (FEM) simulations. By means of these simulations, it was possible to analyze the elastic recovery in the stamping area
It was important to optimise the forming process factors to conclude that the thinning and elastic recovery of the sheet was minimal
Summary
The contour flaps are folded into sheet pieces from 0.5 to 3 mm, with a flat core, generally belonging to ribs or to aeronautical structural elements. By means of hydroforming, smaller stampings are formed in the core of the pieces whose objective is to increase the rigidity without increasing the weight of the piece. In these stampings, the pressure acts on a free radius, forming the sheet by biaxial membrane tensions in the area of the sheet that is in contact with
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
