https://popups.uliege.be/esaform21/index.php?id=3978 Index terms fr 0 https://popups.uliege.be/esaform21/index.php?id=1948 Three-dimensional modelling enables to determine the in-plane material flow in asymmetrical situation. Thus, the distortion of the sheets to be joined can be characterized more exactly. This study shows a method for building up a three-dimensional shear-clinching framework without damage criteria. In fact, the die-sided sheet in shear-clinching was designed as a pre-punched sheet and slugs. The material separation in the die-sided joining partner, which in two-dimensional simulation is often described by macro- and micromechanical fracture criteria, was realised in this study based on a defined contact condition. By means of a shear-cutting simulation, a correlation between the break angle and the separation stress was determined, which was used as a separation criterion in the shear-clinching simulation. The separation line was confirmed using post-particles. To validate this model, the results of the simulation using a quadratic single-point specimen were compared to the experiments with respect to the distortion of the joining partner. In general, the built three-dimensional framework provides for further tool developments with regard to the reduction of distortion in shear-clinching. Tue, 23 Mar 2021 11:13:32 +0100 Mon, 12 Apr 2021 10:10:29 +0200 https://popups.uliege.be/esaform21/index.php?id=1948 https://popups.uliege.be/esaform21/index.php?id=475 In recent years, the concepts of industry 4.0 are widely spreading in many different sectors, from agriculture to home automation, from transportation systems to manufacturing processes. One of the pillars of this concept is related to the use of robotic cells. The focus of the present work is the robotic automated layup of dry fibrous preforms to be employed in liquid composite molding (LCM) processes. In particular, the article describes a software tool developed to simulate the automated placement and layup of fiber fabrics and tissues on complex shape molds by means of a robotic system. The tool has been coded in Matlab language. An end-effector has been appositely designed for the fiber layup and it has been included in the model. The simulation provides as output the path generation and the configuration of the robotic arm and of end effector along the entire layup process. The implemented code has been compared with the commercial software RoboDK. Fri, 19 Mar 2021 22:51:39 +0100 Thu, 08 Apr 2021 22:14:49 +0200 https://popups.uliege.be/esaform21/index.php?id=475 https://popups.uliege.be/esaform21/index.php?id=1640 The manufacturing of oval tubes for automotive components from sheets consists of several steps, from the flat sheet to a tube with expanded ends. It involves roll-bending of tubes, welding and several expansion processes with segmented tools. Forming steps in this process are subject to springback after the release of tools. Finite-element-simulations offer an efficient method to predict the springback behavior. For the industrial application it is important to identify the processes which contribute significantly to springback. At first glance one might expect that the consideration of the whole process chain is required to predict the final shape of such tubes. It turns out, that springback is related to the later stages of the process. The difference in springback behavior of circular and oval tubes is investigated. A simulation model is validated on the basis of experiments for circular tubes and applied to predict the final shape of oval tubes. This offers the perspective to adjust the tooling design at an earlier design stage to respect all the influences in the process on the final geometry and therefore meet tighter tolerances. Mon, 22 Mar 2021 20:21:14 +0100 Mon, 05 Apr 2021 18:35:36 +0200 https://popups.uliege.be/esaform21/index.php?id=1640 https://popups.uliege.be/esaform21/index.php?id=4351 Fiber reinforced thermoplastic composites have shown to be attractive for industry as they can be reused, reshaped, welded and repaired, while keeping mechanical properties on par with thermoset composites. Since thermoplastics usually have high melt viscosities unsuitable for liquid composite molding processes, in-situ synthesis of PA6 from ε-caprolactam is considered. Its reactive mix has low viscosity which allows impregnation. However, the coupled crystallization and polymerization affects the resin viscosity and its flow is altered by the dual-scale permeability of the fiber preform. Thus, to predict the local differences in the thermoplastics properties, a coupled polymerization crystallization model needs to be integrated in the LCM processing simulation at representative scales. This study aims to propose a reliable simulation of the resin flow through a fibrous preform. Hence, viscosity measurements on the reactive mix are achieved using a rheometer with parallel-plate geometry, aiming to associate a viscosity model with the Hillier coupled polymerization-crystallization model previously determined by Vicard. The full chemorheological model will then be integrated into a simulation of LCM process in OpenFOAM®, an open source CFD software in order to follow the extent of the synthesis in the resin flow during the process. As a future work, simulations including microscale tow information extracted from a real textile specimen will permit to investigate the effect of permeability and double scale porosity in fibrous preforms on the final polymerization rate and crystallinity. Thu, 01 Apr 2021 21:46:38 +0200 Thu, 01 Apr 2021 21:46:38 +0200 https://popups.uliege.be/esaform21/index.php?id=4351