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Philippe Boisse - One of the best experts on this subject based on the ideXlab platform.
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A Shell Formulation for Textile Composite Forming Simulations
2020Co-Authors: Renzi Bai, Naïm Naouar, Philippe Boisse, Biao Liang, Julien ColmarsAbstract:The bending stiffness of fibrous reinforcements although weak plays an important role in the wrinkle development simulation, and the fibrous nature of continuous fiber Textile reinforcement modifies their behavior especially the bending. The slippage between fibers and the quasiinextensibility of fibers make the theory of Mindlin and Kirchhoff not verified during the bending process of multi-layer reinforcement. Therefore, a specific shell formulation is proposed in this article. This shell approach can not only determine the transverse slippage between layers but also the rotations of material director.
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A specific 3D shell approach for Textile Composite reinforcements under large deformation
Composites Part A: Applied Science and Manufacturing, 2020Co-Authors: Renzi Bai, Julien Colmars, Naïm Naouar, Philippe BoisseAbstract:The deformation of Textile Composite reinforcements is strongly conditioned by their fibrous composition. Standard plate and shell theories are based on kinematic assumptions that are not verified for Textile reinforcements. A 3D shell approach specific to fibrous reinforcements is proposed. It is based on two specificities: the inextensibility of the fibres and the possible slippage between the fibres. The approach is developed in a continuum-based shell element. The form of the virtual work reflects the specificities of the deformation of the fibrous reinforcements. It takes into account the tensile and bending stiffness of the fibres. Friction between fibres is taken into account in a simple way in connection with bending. The present approach is based on the actual physics of the deformation of the Textile reinforcements. It makes it possible to simulate the 3D deformations of Textile reinforcements and provides displacements and strains for all points in the fabric thickness and the proper rotations of the material normal.
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Textile Composite Damage Analysis Taking into Account the Forming Process
Materials, 2020Co-Authors: Marjorie Jauffret, Aldo Cocchi, Naïm Naouar, Christian Hochard, Philippe BoisseAbstract:The internal structure of Composite materials is modified during manufacturing. The formation of woven prepregs or dry preforms changes the angle between the warp and weft yarns. The damage behaviour of the consolidated Composite is modified by these changes of angle. It is important when designing a Composite part to consider this modification when calculating the damage in order to achieve a correct dimensioning. In this paper, a damage calculation approach of the consolidated Textile Composite that takes into account the change in orientation of the yarns due to forming is proposed. The angles after forming are determined by a simulation of the draping based on a hypoelastic behaviour of the woven fabric reinforcement. Two orthogonal frames based on the warp and weft directions of the Textile reinforcement are used for the objective integration of stresses. Damage analysis of the cured woven Composite with non-perpendicular warp and weft directions is achieved by replacing it with two equivalent Unidirectional (UD) plies representing the yarn directions. For each ply, a model based on Continuum Damage Mechanics (CDM) describes the progressive damage. Two examples are presented, a bias extension specimen and the hemispherical forming coupon. In both cases, the angles between the warp and weft yarns are changed. It is shown that the damage calculated by taking into account these angle changes is greatly modified.
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The Need to Use Generalized Continuum Mechanics to Model 3D Textile Composite Forming
Applied Composite Materials, 2018Co-Authors: Philippe Boisse, R. Bai, Julien Colmars, B. Liang, Nahiene Hamila, Angela MadeoAbstract:3D Textile Composite reinforcements can generally be modelled as continuum media. It is shown that the classical continuum mechanics of Cauchy is insufficient to depict the mechanical behavior of Textile materials. A Cauchy macroscopic model is not capable of exhibiting very low transverse shear stiffness, given the possibility of sliding between the fibers and simultaneously taking into account the individual stiffness of each fibre. A first solution is presented which consists in adding a bending stiffness to the tridimensional finite elements. Another solution is to supplement the potential of the hyperelastic model by second gradient terms. Another approach consists in implementing a shell approach specific to the fibrous medium. The developed Ahmad elements are based on the quasi-inextensibility of the fibers and the bending stiffness of each fiber.
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The bias-extension test for the analysis of in-plane shear properties of Textile Composite reinforcements and prepregs: a review
International Journal of Material Forming, 2017Co-Authors: Philippe Boisse, Nahiene Hamila, E. Guzman-maldonado, A. Madeo, G. Hivet, F. Dell’isolaAbstract:The bias-extension test is a rather simple experiment aiming to determine in-plane shear properties of Textile Composite reinforcements. However the mechanics during the test involves fibrous material at large shear strains and large rotations of the fibres. Several aspects are still being studied and are not yet modeled in a consensual manner. The standard analysis of the test is based on two assumptions: inextensibility of the fibers and rotations at the yarn crossovers without slippage. They lead to the development of zones with constant fibre orientations proper to the bias-extension test. Beyond the analysis of the test within these basic assumptions, the paper presents studies that have been carried out on the lack of verification of these hypothesis (slippage, tension in the yarns, effects of fibre bending). The effects of temperature, mesoscopic modeling and tension locking are also considered in the case of the bias-extension test.
Xiaogang Chen - One of the best experts on this subject based on the ideXlab platform.
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Effects of plies assembling on Textile Composite cellular structures
Materials & Design, 2007Co-Authors: Xincai Tan, Xiaogang Chen, Paul Conway, Xiu-tian YanAbstract:Cellular structures are generally assembled with face sheet plies in their application. It is necessary to understand the influence of assembled plies on deformation and energy absorption before using Textile Composite cellular structures in engineering design. In this paper, effects of ply assembly, outer ply material, outer ply thickness, and loading area on energy absorption and deformation of the applied structure including cellular structure and face sheet plies are investigated. Three-dimensional finite element analyses are carried out employing orthotropic mechanical properties of the applied materials, Textile Composite, wood, E-glass, aluminium alloy 2024-T3 and unidirectional fiber-epoxy Composite T-300. The predicted results show that deformation and distributed strain energy density of both outer and inner surfaces of the applied structure are significantly affected by ply assembly, outer ply material, outer ply thickness, and loading area.
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parameters affecting energy absorption and deformation in Textile Composite cellular structures
Materials & Design, 2005Co-Authors: Xiaogang ChenAbstract:Cellular structures currently applied in various engineering fields are mainly made of metals and papers. To engineering design Textile Composite cellular structures, in this paper, comparisons of various essential structural parameters affecting energy absorption and deformation are carried out. These parameters include the opening angle, the cell-wall length, the cell-wall thickness, the bonded cell-wall length, and the bonded cell-wall thickness. The structure geometries are created by in-house computer package which exports IGES files. Two-dimensional finite element analyses are conducted by MSC.Marc Mentat 2001 which imports these IGES files to numerical calculation. Orthotropic mechanical properties of the Textile Composite cellular structure laminate are applied for the finite element analyses. It is found that the opening angle, the cell-wall length and the cell-wall thickness affect significantly energy absorption and deformation. Strain energy density concentrations appear very seriously around the cell corners during quasi-static impact.
Matthew R Begley - One of the best experts on this subject based on the ideXlab platform.
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generating virtual Textile Composite specimens using statistical data from micro computed tomography 3d tow representations
Journal of The Mechanics and Physics of Solids, 2012Co-Authors: R G Rinaldi, Matthew Blacklock, Hrishikesh Bale, Matthew R BegleyAbstract:Recent work presented a Monte Carlo algorithm based on Markov Chain operators for generating replicas of Textile Composite specimens that possess the same statistical characteristics as specimens imaged using high resolution x-ray computed tomography. That work represented the Textile reinforcement by one-dimensional tow loci in three-dimensional space, suitable for use in the Binary Model of Textile Composites. Here analogous algorithms are used to generate solid, three-dimensional (3D) tow representations, to provide geometrical models for more detailed failure analyses. The algorithms for generating 3D models are divided into those that refer to the topology of the Textile and those that deal with its geometry. The topological rules carry all the information that distinguishes Textiles with different interlacing patterns (weaves, braids, etc.) and provide instructions for resolving interpenetrations or ordering errors among tows. They also simplify writing a single computer program that can accept input data for generic Textile cases. The geometrical rules adjust the shape and smoothness of the generated virtual specimens to match data from imaged specimens. The virtual specimen generator is illustrated using data for an angle interlock weave, a common 3D Textile architecture.
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generating virtual Textile Composite specimens using statistical data from micro computed tomography 1d tow representations for the binary model
Journal of The Mechanics and Physics of Solids, 2012Co-Authors: Matthew Blacklock, Hrishikesh Bale, Matthew R BegleyAbstract:A Monte Carlo algorithm is defined for generating replicas of Textile Composite specimens that possess the same statistical characteristics as specimens imaged using high resolution computed tomography. The Textile reinforcement is represented by one-dimensional tow loci in three-dimensional space, which are easily incorporated into the Binary Model of Textile Composites. A tow locus is expressed as the sum of non-stochastic, periodic variations in the coordinates of the tow centroid and stochastic, non-periodic deviations. The non-stochastic variations have period commensurate with the dimensions of the unit cell of the Textile, while the stochastic deviations, which describe geometrical defects, exhibit correlation lengths that may be incommensurate with the unit cell. The model is calibrated with data deduced in prior work from computed tomography images. The calibration obviates the need for assuming any ideal shape functions for the tow loci, which can take very general form. The approach is therefore valid for a wide range of Textile architectures. Once calibrated, a Markov Chain algorithm can generate numerous stochastic replicas of a Textile architecture very rapidly. These virtual specimens can be much larger than the real specimens from which the data were originally gathered, a necessary feature when real specimen size is limited by the nature of high resolution computed tomography. The virtual specimen generator is illustrated using data for an angle interlock weave.
Youqi Wang - One of the best experts on this subject based on the ideXlab platform.
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Applications of Digital Element Approach in Textile Mechanics and Textile Composite Mechanics
American Society for Composites 2020, 2020Co-Authors: Youqi Wang, Agniprobho Mazumder, Binghui Liu, Chian-fong YenAbstract:The digital element approach (DEA) was originally developed to determine the geometry of Textile Composite preforms. With DEA, a fabric is considered as an assembly of unit cells; a unit cell as an assembly of yarns; and a yarn as an assembly of digital filaments. Each digital filament is discretized into a chain of digital elements. Contact force between digital filaments is calculated based on distance between them. During the past ten years, software, DFMA, has been developed based on DEA to simulate fabric deformation under external force in several areas of Textile Composite mechanics: determination of fabric microgeometry, simulation of fabric deformation in Composite manufacturing processes, such as draping, forming and molding, and generation of conformal FEM meshes for Composites with complex shapes. In this paper, principles of DEA are examined first. Applications of DFMA in the following four areas are then reviewed: 1) determine geometries of Textile Composite preforms with complex shapes, 2) generate conformal FE meshes for Textile Composites, 3) determine strength and shear characteristics of Textile Composite preforms and 4) simulate draping, forming and molding processes of Textile Composite preforms. Multiple examples are presented in detail to illustrate applications from each of the above four areas.
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a structured method to generate conformal fe mesh for realistic Textile Composite micro geometry
Composite Structures, 2020Co-Authors: Agniprobho Mazumder, Youqi WangAbstract:Abstract A procedure is developed to generate a conformal finite element mesh of a Textile Composite unit cell with a complex micro-geometry with the aim of improving the accuracy of micro-mechanics analysis. A realistic micro-geometry of a Textile Composite unit cell is initially generated by using a fiber level dynamic relaxation approach. Yarn surfaces are then discretized into triangle elements. An algorithm is established to remove inter-yarn interferences and gaps induced by numerical errors. The unit cell is first divided into a uniform cuboid element mesh, which is later modified and converted to a conformal finite element (FE) mesh through of a process of node shifting and element splitting. In the conformal mesh, the element boundary perfectly matches the yarn-to-yarn interface. Compatibility between elements is ensured. The quality of each element is examined. The mesh can be input to commercial FEM softwares for Composite stress analysis.
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conforming element mesh for realistic Textile Composite micro geometry
Proceedings of the American Society for Composites — Thirty-third Technical Conference, 2018Co-Authors: Agniprobho Mazumder, Youqi WangAbstract:In recent years, several computer tools, e.g., DFMA, TexGen and WiseTex have been developed to derive realistic yarn-level micro-geometries for Textile Composites. However, due to numerical errors, the generated micro-geometries by these computer design tools have unavoidably exhibited artificial surface interferences or narrow gaps between yarns. It is therefore problematic to directly input the micro-geometry into a commercial FEM code to generate a conforming element mesh. In this paper, a procedure is developed to generate a conforming FE mesh that matches actual yarn-toyarn and yarn-to-matrix surface inside a Textile Composite with a complex microgeometry. It improves the accuracy of micro-mechanics analysis. The procedure divides into five steps. Initially, the unit cell domain is discretized into a uniform cuboid finite element mesh and the yarn surface is discretized into triangular plane elements. The second step consists of calculating the intersecting points between yarn surface triangle elements and mesh gridlines in the z-direction. The third step is the removal of numerical error driven artificial surface interferences or narrow gaps between yarns. If the distance between two intersection points from two adjacent yarns is smaller than a specified tolerance, the two adjacent intersecting points are merged to the mid-point. A material type, defined by yarn number, interface or matrix, is assigned to each node. In the fourth step, the initial uniform cuboid finite element mesh is modified so as to match yarn boundaries to the finite element mesh. In the final step, material types/yarn numbers are assigned to each element based on nodal material types. If an element is composed of nodes of two different material types, it is split into two or more elements. As such, a conforming FEM mesh, which matches the element boundary to the yarn-to-yarn or yarn-to-matrix interface, can be generated.
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mechanics of Textile Composites micro geometry
Composites Science and Technology, 2008Co-Authors: Yuyang Miao, Eric Zhou, Youqi Wang, B A CheesemanAbstract:Abstract Textile fabric geometry determines Textile Composite properties. Textile process mechanics determines fabric geometry. In previous papers, the authors proposed a digital element model to generate Textile Composite geometry by simulating the Textile process. The greatest difficulty encountered with its employment in engineering practice is efficiency. A full scale fiber-based digital element analysis would consume huge computational resources. Two advances are developed in this paper to overcome the problem of efficiency. An improved contact-element formulation is developed first. The new formulation improves accuracy. As such, it permits a coarse digital element mesh. Then, a static relaxation algorithm to determine fabric micro-geometry is established to replace step-by-step Textile process simulation. Employing the modified contact element formulation in the static relaxation approach, the required computer resource is only 1–2% of the resource required by the original process. Two critical issues with regards to the digital element mesh are also examined: yarn discretization and initial yarn cross-section shape. Fabric geometries derived from digital element analysis are compared to experimental results.
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Micro-Stress and Failure Analysis of Textile Composites
2003Co-Authors: Youqi WangAbstract:Abstract : Project objectives are the development of more optimal mechanics approaches for Textile Composite design and failure analysis. Tailoring of the Textile Composite microstructure is one of the most pressing research issues in Textile Composite design. The Textile pre-forming process determines the microstructure of the Textile preform. Preform microstructure determines Textile Composite micro-stress distribution. Development of a numerical approach that facilitates establishment of relations between Textile microstructures and Textile processes is, therefore, critical. In this project, two new numerical methods are developed. The first is a digital element simulation approach for Textile mechanics. It enables simulation of the Textile process as well as simulation of Textile preform deformation. As a result, detailed knowledge of the Textile preform microstructure becomes obtainable. The second method developed in this project is a heterogeneous element method for the micro-stress analysis of Textile Composites. Formulation of a heterogeneous element guarantees that both the equilibrium conditions and the continuity of displacement at the interface are satisfied. Yet, it allows for interface stress and strain jump. Because the formulation reflects the actual physical situation at the interface, it provides a much more accurate result than conventional approaches if the same mesh is used.
Xiu-tian Yan - One of the best experts on this subject based on the ideXlab platform.
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Effects of plies assembling on Textile Composite cellular structures
Materials & Design, 2007Co-Authors: Xincai Tan, Xiaogang Chen, Paul Conway, Xiu-tian YanAbstract:Cellular structures are generally assembled with face sheet plies in their application. It is necessary to understand the influence of assembled plies on deformation and energy absorption before using Textile Composite cellular structures in engineering design. In this paper, effects of ply assembly, outer ply material, outer ply thickness, and loading area on energy absorption and deformation of the applied structure including cellular structure and face sheet plies are investigated. Three-dimensional finite element analyses are carried out employing orthotropic mechanical properties of the applied materials, Textile Composite, wood, E-glass, aluminium alloy 2024-T3 and unidirectional fiber-epoxy Composite T-300. The predicted results show that deformation and distributed strain energy density of both outer and inner surfaces of the applied structure are significantly affected by ply assembly, outer ply material, outer ply thickness, and loading area.
