Advanced numerical tool for composite woven fabric preforming (original) (raw)
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Present State of the Art of Composite Fabric Forming: Geometrical and Mechanical Approaches
Materials, 2009
Continuous fibre reinforced composites are now firmly established engineering materials for the manufacture of components in the automotive and aerospace industries. In this respect, composite fabrics provide flexibility in the design manufacture. The ability to define the ply shapes and material orientation has allowed engineers to optimize the composite properties of the parts. The formulation of new numerical models for the simulation of the composite forming processes must allow for reduction in the delay in manufacturing and an optimization of costs in an integrated design approach. We propose two approaches to simulate the deformation of woven fabrics: geometrical and mechanical approaches.
Advanced Composites Letters, 2000
The present study concerns the modelling of the behaviour of pre-impregnated woven fabric during the forming process. The mechanical approach is based on a mesostructural model. It allows us to take into account the mechanical properties of fibres and resin and the various dominating mode of deformation of woven fabrics during the forming process. Shear and tensile tests of composite fabric specimens are proposed and compared with the experimental results in order to demonstrate the efficiency of our approach. Different numerical simulations and experiments of shaping process have been carried out in order to validate the proposed computational formulation. The various forming parameters examined have included the initial shape of fabric, fibre orientations and viscosity of resin.
The Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section, 2015
The structure of the fabric, when it is used as a composite reinforcement, have a major influence on the mechanical properties of a fabric reinforced composite material. Composite design and analysis requires a computer tool, not only to link composite properties to fabric micro and macro geometry, but also to link fabric micro geometry to the weaving pattern. The complex structure of textile composite comprises of several hierarchical levels: macro (composite component or sub-component), meso (unit cell of the reinforcement structure) and micro (fibre placement inside yarns and fibrous plies). The most specific to textile composites is meso level, where the structure dependent behaviour of the material is most pronounced. This is the most important level at which the optimization of the structure and the constituents should be performed. Continuous and discrete approaches are possible for the forming simulations of composite textile reinforcements because of their multi-scale struc...
Modelling of fabric draping: Finite elements versus a geometrical method
Thermoplastic composite materials can be processed by Rubber Press Forming at elevated temperatures. Process specific boundary conditions are difficult to incorporate in the classical geometric drape simulation methods. Therefore, a fabric reinforced fluid model was implemented in the Finite Element package DIEKA, which is capable of modelling the boundary conditions as well. The model predictions of both types of simulations are compared for a double dome geometry, having separated contact areas, leading to different results.
Discrete Modelling of Non-Crimp Fabric Multi-Layer Preforming Processes
The manufacture of textile-reinforced composites typically requires the preforming of dry textile fabrics. During this process the material is subjected to complex loading where the coupling of tensile, bending, shear and compressive forces result in deformations to the internal architecture of the textile. To determine the extent of these deformations a discrete numerical modelling method at the tow level has been developed. The present study explores the method's ability to capture local and global deformations which occur in non-crimp fabrics, specifically to capture the onset of deformations that occur due to tow-stitch interactions and the forming of multiple layers. Initially proposed by El Said et al. for 3D woven fabrics, the method utilises a two-step process. The first step generates an accurate as-woven unit cell geometry using a high fidelity digital element method where the tows are composed of bundles of beam elements. The as-woven geometry is then extracted and te...
Geometrical and mechanical draping of composite fabric
Revue européenne des éléments finis, 2005
This paper presents an optimization based method for simulation of forming processes of woven fabric reinforced composites. Two approaches are proposed for the simulation of the forming of woven fabric: geometrical and mechanical. The geometrical approach is based on a fishnet model. It is well adapted to pre-dimensioning fabrics and to give a suitable quantification of the resulting flat patterns. The mechanical approach is based on a mesostructural model. It allows us to take into account the mechanical properties of prepreg fabric and the various dominating mode of deformation of woven fabrics during the forming process. Some numerical simulations of forming process are proposed and compared with the experimental results in order to demonstrate the efficiency of our approaches. RÉSUMÉ. Ce papier traite le problème d'optimisation de la mise en forme des tissus composites pré-imprégnés. Deux approches complémentaires sont proposées pour modéliser le drapage de ces matériaux : une approche géométrique et une approche mécanique. La première est basée sur le modèle du filet et s'inscrit dans une démarche de prédimensionnement, la seconde est basée sur une approche mesostructurale et s'inscrit dans une perspective d'optimisation de la conception et la fabrication de pièces composites.
A woven reinforcement forming simulation method. Influence of the shear stiffness
Computers & structures, 2006
A simulation method is proposed for forming processes of fabrics used as reinforcements of composite materials. It uses specific finite elements made of woven material. The nodal interior loads are deduced from yarn tensile strain energy and woven cell shear energy. A picture frame shear test is presented. Optical measures permit to analyse the strains in yarns at microlevel for the different stages of the shear test. The influence of shearing in the formulation is studied on two forming simulations. It is shown that taking shear into account permits the appearance and the development of wrinkles when the locking angle is overcome.
Kinematic modelling of the weaving process applied to 2D fabric
Journal of Industrial Textiles, 2014
Weaving process simulation of fabrics, used as fibrous reinforcements in composite applications, is presented in this article. The mechanical modelling of textile structures requires an accurate geometric representation of the woven elementary cell including complex interlacements of yarns and compactions.