https://popups.uliege.be/esaform21/index.php?id=1685 Index terms fr 0 https://popups.uliege.be/esaform21/index.php?id=4298 In many branches of production, components using large number of joints are combined together to make complex structures. The use of mechanical joining techniques offers the possibility to join structures with a wide range of material/geometry configurations. Due to changing in material properties during the production of formed parts, the robustness of the joint must be guaranteed. In this regard, a numerical method has been developed to predict the geometrical properties of the joint as a function of pre-straining of the metal sheets. In this way, the material combination and the joining tools are to be considered. The resulting metamodels were used to estimate the robustness of the joining process. In this study, the method is extended by a numerical load capacity model, which is generated from the joining process model using an automatic algorithm. The simulation model used for predicting the load capacity is validated by experiments. It is shown that the resulting automatic method is able to completely map a process chain and to predict the load capacity of the mechanical joints under consideration of the pre-strain. Furthermore, the correlation between the pre-strain and the load capacity is presented. Thu, 01 Apr 2021 17:54:38 +0200 Mon, 12 Apr 2021 11:38:39 +0200 https://popups.uliege.be/esaform21/index.php?id=4298 https://popups.uliege.be/esaform21/index.php?id=2781 In lightweight design, clinching is a cost-efficient solution as the joint is created through localized cold-forming of the joining parts. A clinch point’s quality is usually assessed using ex-situ destructive testing methods. These, however, are unable to detect phenomena immediately during the joining process. For instance, elastic deformations reverse and cracks close after unloading. In-situ methods such as the force-displacement evaluation are used to control a clinching process, though deviations in the clinch point geometry cannot be derived with this method. To overcome these limitations, the clinching process can be investigated using in-situ computed tomography (in-situ CT). However, a clinching tool made of steel would cause strong artefacts and a high attenuation in the CT measurement, reducing the significance of this method. Additionally, when joining parts of the same material, the sheet-sheet interface is hardly detectable. This work aims at identifying, firstly, tool materials that allow artefact-reduced CT measurements during clinching, and, secondly, radiopaque materials that can be applied between the joining parts to enhance the detectability of the sheet-sheet interface. Therefore, both CT-suitable tool materials and radiopaque materials are selected and experimentally investigated. In the clinching process, two aluminium sheets with radiopaque material in between are clinched in a single-step (rotationally symmetric joint without cut section). It is shown that e.g. silicon nitride is suited as tool material and a tin layer is suitable to enhance the detectability of the sheet-sheet interface. Wed, 24 Mar 2021 18:59:21 +0100 Sat, 10 Apr 2021 13:51:32 +0200 https://popups.uliege.be/esaform21/index.php?id=2781 https://popups.uliege.be/esaform21/index.php?id=3801 Mon, 29 Mar 2021 14:41:07 +0200 Thu, 08 Apr 2021 20:33:47 +0200 https://popups.uliege.be/esaform21/index.php?id=3801 https://popups.uliege.be/esaform21/index.php?id=4293 Thermally supported clinching (Hotclinch) is a novel promising process to join dissimilar materials. Here, metal and fibre-reinforced thermoplastics (FRTP) are used within this single step joining process and without the usage of auxiliary parts like screws or rivets. For this purpose, heat is applied to improve the formability of the reinforced thermoplastic. This enables joining of the materials using conventional clinching-tools. Focus of this work is the modelling on mesoscopic scale for the numerical simulation of this process. The FTRP-model takes the material behaviour both of matrix and the fabric reinforced organo-sheet under process temperatures into account. For describing the experimentally observed phenomena such as large deformations, fibre failure and the interactions between matrix and fibres as well as between fibres themselves, the usage of conventional, purely Lagrangian based FEM methods is limited. Therefore, the combination of contact-models with advanced modelling approaches like Arbitrary-Lagrangian-Eulerian (ALE), Coupled-Eulerian-Lagrangian (CEL) and Smooth-ParticleHydrodynamics (SPH) for the numerical simulation of the clinching process are employed. The different approaches are compared with regard to simulation feasibility, robustness and results accuracy. It is shown, that the CEL approach represents the most promising approach to describe the clinching process. Thu, 01 Apr 2021 17:51:44 +0200 Thu, 01 Apr 2021 17:51:44 +0200 https://popups.uliege.be/esaform21/index.php?id=4293