Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2019
Thesis Language: Turkish
Student: GÜRHAN YILGIN
Supervisor: OĞUZHAN YILMAZ
Abstract:Sheet metal forming methods are widely used in many sectors, especially in the aerospace and automotive. Hydroforming with membrane diaphragm, which is one of these methods, is mostly preferred due to its ease of production and its ability to form many parts. The number of convex contoured parts is quite high in the aviation industry. While these parts are formed by hydroforming method, it is observed as a common error that wrinkles occurring during sheet metal forming. As a result of this wrinkling error, waste of time and cost increase occur due to the scrap parts. By increasing predictability of this wrinkle condition before production, waste of time and high cost will be prevented. Some of the parameters that cause wrinkling are variables such as the material of the part to be produced, the contour convex radius, the flange length and the thickness of the material. In this thesis work, the behavior of contoured parts formed by hydroforming with membrane diaphragm method is investigated experimentally. The experimental setup is prepared and forming processes are performed at the specified pressure and parameters. For forming processes Al-2024-O and Al-2024-W sheet metal materials, which are widely used in the aerospace industry, are selected. In the experiments, sheet metal materials were chosen in thicknesses of 0,635 mm, 1,27 mm, 1,60 mm, and 2,0 mm. The parts which has 20 mm, 30 mm, 40 mm flange lengths are formed by hydroforming with diaphragm in the tool with different radius contour. In the forming results, intense wrinkling occurred on the parts with 125 mm radius contour. It is concluded that the wrinkling decreases significantly for the part forming of 2,00 mm thick material. The effect of the parameters determined in accordance with all the results obtained is examined. The conditions in which the wrinkling occurred and the safe areas are identified and their graphs are presented. In addition, the forming process is analyzed in PAM-STAMP analysis program and compared with experimental results In the comparison, it is determined that the analysis results are not the same with the experimental results accurately. Therefore, experimental study is important and necessary. The obtained results helps to reduce the loss of product time and reductive in cost.