https://popups.uliege.be/esaform21/index.php?id=112 Publications of Auteurs Bernd Engel fr 0 https://popups.uliege.be/esaform21/index.php?id=3756 This study presents the results of a double dome forming study for fiber reinforced thermoplastics to give an estimation about wrinkles size and fiber angle values. The parts were formed with an industry-oriented process at different forming temperatures and fiber directions (0 °/ 90 ° and ±45 °). They were formed without blank holder to allow wrinkling. The investigated material is a glass fiber –reinforced polyamide 6 with three layers of twill fabric (TEPEX® Dynalite 102-RG600(3)/47 %). The wrinkles are measured with a laser scanner. The shear angles were calculated using image analysis in MATLAB. It determines the fiber directions and calculates the fiber angles at their crossing points. Afterwards, areas with positive and negative shear angle values will be identified and discussed: These areas are in an axially symmetrical formation. At one side there are positive shear angles and on the other side there are negative shear angles. But results show, that absolute values differ. Furthermore, the results show, that shear angles increase with increasing forming temperatures and wrinkles size decrease. The results of this work will be used for the validation of FE forming models of double dome part in further studies. Mon, 29 Mar 2021 14:26:34 +0200 Thu, 08 Apr 2021 20:11:33 +0200 https://popups.uliege.be/esaform21/index.php?id=3756 https://popups.uliege.be/esaform21/index.php?id=2742 Rotary draw bending (RDB) is a forming process that is commonly used to bend tubes with small wall thicknesses and small bending radii. One of the limitations of this process is the formation of wrinkles caused by compressive stress on the inner bend. In order to design the bending process without wrinkles and to determine the necessary process parameters, adjustment tests are required. Within this work, a fuzzy controller is to be developed which automatically prevents the formation of wrinkles and thus eliminates the need for time-consuming set-up tests to determine the necessary process parameters. The fuzzy controller is based on fuzzy set theory and fuzzy logic. In connection with a rule base it is possible to simulate the human decision process. A fuzzy controller is programmed based on a max-min controller, with the required rules resulting from previous bending tests. After the fuzzy controller has been implemented, it must be connected to the bending machine by suitable interfaces. The input values, which indicate wrinkles, are measured by sensors during the bending process and provide the controller with data. The fuzzy controller then uses the control base to specify the required control variables. After programming has been completed, practical validation tests were carried out. In the validation tests using different tube wall thicknesses and materials, a significant reduction of wrinkles is achieved. Bending of completely wrinkle-free tubes is also possible due to the automated finding of optimal tool settings. Using the fuzzy controller eliminates the need for costly adjustment bends, resulting in significant time and cost savings. Wed, 24 Mar 2021 18:54:12 +0100 Fri, 02 Apr 2021 16:05:33 +0200 https://popups.uliege.be/esaform21/index.php?id=2742 https://popups.uliege.be/esaform21/index.php?id=1870 In a modern production environment, flexible manufacturing methods are important because an overall trend towards mass customization and on-demand production is observed. Kinematic and incremental forming methods with generic tools can provide a large product variation but a deeper understanding of the forming mechanisms is required for process modelling, e.g. Incremental Swivel Bending (ISB). Particularly crucial is to identify the influences on the forming zone in order to purposefully control the material flow of a forming process. For a bending process where the bending moment is transmitted by clamping tools, this paper presents a method to alter the contact pressure distribution in order to affect the angular size and strain gradient of the forming zone. In the light of these results, the presented method can be deployed for a tooling with adaptive contact pressure to directly influence material flow, in particular using generic tools to overall provide a better control of flexible forming methods. Tue, 23 Mar 2021 10:02:38 +0100 Mon, 12 Apr 2021 09:55:59 +0200 https://popups.uliege.be/esaform21/index.php?id=1870