In recent decades, the use of aluminium alloys is developed in the automotive industry with regard to the need for lightweight and anti-corrosion components, one of which is AA7075 Al alloy. In this study, the multi-step deep drawing process of AA7075 aluminium sheets under various blank holder forces is investigated through a numerical simulation and is then validated with experimental results. Simulations were conducted by ABAQUS finite element software, and the influences of the blank holder force on the wrinkling height, rupture occurrence and thickness distribution of the sheet were studied. The optimum amount of blank holder force at each drawing step is determined so that the height of wrinkling, and the thinning percentage do not exceed the permissible value. Based on the results, the blank holder force magnitude should be considered descending during the four successive steps to achieve more uniform thickness distribution, and also the wrinkling height could be reduced by increasing the blank holder force in the analysed force range. The optimum amount of blank holder force in the four drawing steps was 28000, 2500, 1500 and 600 N, respectively. In general, the minimum thickness was created in the corner of the punch. The results also showed that an excessive increase in the blank holder force in order to eliminate the wrinkling caused the thinning percentage to increase. Finally, a good accordance between the experimental and numerical results was observed. Manuscript profile

In this study, hole-flanging of a dual-phase steel sheet is conducted using incremental forming approach. In this process, a hole with a certain diameter is pre-cut on a sheet. Then, this hole is transformed into a cylindrical flange shapes, by contacting the forming tool with the hole edges. During the process, the tool is moved in spiral paths. The parameters affecting the height and thickness distribution of the formed flange include axial step, radial step, and rotational speed of the tool. Results show that the axial step has the most significant effect on the process, among other parameters; when the axial step is tripled, the flange thickness increases by 19%. On the other hand, a decrease in the radial step decreases the flange edge thickness. When the radial step is tripled, the flange thickness increases by 8%, while the flange height decreases about 3%. Manuscript profile

Reduction of weight and increase of corrosion resistance are among the advantages of applications of aluminum alloys in the automotive industry. Low formability at room temperature is the major problem in the forming of these alloys. This problem is due to alloy elements that limit the number of slip planes at room temperature. Forming at a high temperature can improve the formability of metals. In this paper, the warm hydroforming of AA1050 aluminum tubes has been studied numerically. A warm tube hydroforming setup was designed and fabricated. Aluminum tubes were formed at high temperatures. Numerical simulation of process is performed using MSC. Marc commercial software and thickness distribution were studied at various temperatures. Results showed that increasing temperature leads to a much better thickness distribution. The pressure curves which were obtained using available equations for forming at room temperature have been modified to decrease thinning in the final part. Simulations were performed in two states which are called constrained bulge and free bulge. To produce a part without any wrinkling and also to obtain minimum thinning, an axial feeding curve is suggested. Manuscript profile

Hydromechanical deep drawing is a new process in sheet metal forming. In hydromechanical deep drawing, a chamber of fluid replaces the matrix and the final form of part is determined based on the form of rigid punch. This process can produce parts with more drawing ratios than traditional deep drawing. In this paper, the hydromechanical deep drawing (HDD) of square parts was studied using the finite element method (FEM), and the effects of different parameters of the process such as pre-bulging pressure, chamber pressure, and friction coefficient on the thinning were investigated. Simulation is done using Abaqus software. St12 sheets have been formed and the effect of parameters on thickness distribution is determined. A study was also carried out using an experimental setup to verify the FEM results. Results show that flange wrinkling decreases by increasing chamber pressure. Also selecting appropriate pre-bulging pressure can decrease the thinning significantly. Finally, the numerical results were compared with experimental data. Manuscript profile