https://popups.uliege.be/esaform21/index.php?id=380 Index terms fr 0 https://popups.uliege.be/esaform21/index.php?id=3740 Fibre-reinforced thermoplastics (FRTP), such as organo sheets or laminates, are increasingly being used in large-scale automotive production. The high weight-saving potential, high specific strengths and stiffnesses as well as processing times suitable for large-scale production are some of the reasons for using these materials. However, the formability of such semi-finished products is severely limited by the fibre reinforcement, which can lead to fibre breakage, fibre displacement or wrinkling in complex-shaped components. In order to increase the formability, an FRTP semi-finished product is developed, which consists of discontinuous tapes. Due to the local sliding of the tape sections, a pseudo-plastic material behaviour is achieved. Experimental uniaxial tensile tests at elevated temperatures are used to investigate the forming behaviour of the material for different tape lengths and overlap lengths. Subsequently, this tensile test is numerically modelled in order to fit the pseudo-plasticity to the experimental data by a virtual parameter identification. With the help of the parameters determined from the numerical tensile test, the sliding behaviour of the tape sections can be used for forming simulations in order to achieve a higher prediction quality. Mon, 29 Mar 2021 14:23:33 +0200 Thu, 08 Apr 2021 20:06:31 +0200 https://popups.uliege.be/esaform21/index.php?id=3740 https://popups.uliege.be/esaform21/index.php?id=2659 Forming simulations are a cost-effective solution to mitigate process-induced defects. The models developed to simulate the forming process require material property data for the dominant deformation mechanisms: intra-ply shear, bending, and inter-ply friction. These mechanisms are considered independent, and material property data has to be derived from experimental data for each mechanism separately. However, it is known that the material response to the deformation mechanisms is correlated, as the choice of matrix, fibre, and reinforcement influences the response to all mechanisms. Over the past years a large variety of thermoplastic composites have been characterised, covering a broad field of applications in automotive and aerospace industry. This makes it possible to start correlating the forming behaviour of thermoplastic composites. In this study, the effect of the constituents of a composite on the forming behaviour is analysed. To this end, a Bayesian cross-classified multilevel model with varying intercepts was applied, and the effects found by the model were analysed. Correlations were found between the effect of the constituents and their properties. The study confirms that the matrix material is an important indicator for the forming behaviour. Wed, 24 Mar 2021 18:38:43 +0100 Fri, 02 Apr 2021 15:36:53 +0200 https://popups.uliege.be/esaform21/index.php?id=2659 https://popups.uliege.be/esaform21/index.php?id=376 In this study, a sequential thermoforming and squeeze flow simulation approach for Glass Mat Thermoplastic (GMT) material is proposed and applied to a hat section geometry using input properties based upon Tepex flowcore, a long glass fiber reinforced polyamide (PA/GF) mat manufactured by Lanxess. First, a fully-coupled thermomechanical simulation is conducted based on a purely Lagrangian description, to efficiently capture thermoforming. Subsequently, relevant state variables are mapped and initialized for a Coupled-Eulerian-Lagrangian (CEL) approach. The CEL approach is adopted to accurately capture squeeze flow, which is not possible by a purely Lagrangian description. While numerical techniques differ, both approaches use the same three-dimensional and thermomechanical constitutive equations including an equation of state, a nonlinear viscosity model, and crystallization kinetics, implemented through a material user-subroutine (VUMAT) for the commercially available simulation software package ABAQUS/Explicit. Fri, 19 Mar 2021 17:35:11 +0100 Tue, 30 Mar 2021 09:42:01 +0200 https://popups.uliege.be/esaform21/index.php?id=376