Christophe Binetruy

• Professor
• Centrale Nantes

High-performance C-SMCs typically consist of long carbon fibre reinforcement with high fibre content and can be compression moulded at elevated temperatures and pressures to form parts with complex geometries. Squeeze flow testing has been increasingly adopted for experimentally characterising the flow behaviour of C-SMCs, but the reliability and r...

During Liquid Composite Molding, a fibrous reinforcement is impregnated with liquid resin. Process design requires knowledge of the reinforcement permeability for fluid flow, but until recently, there has been no standard available for its measurement. In 2023, following decades of benchmarking activities and a standardization project, an ISO stand...

The liquid resin infusion (LRI) process is continuously used for manufacturing large industrial parts across various sectors, yet it poses challenges due to its inherent variabilities. The MONOCLE research project, led by the Jules Verne French Institute and industrial partners, aims to develop a digital monitoring approach for complex parts during...

Permeability is a fundamental property of porous media. It quantifies the ease with which a fluid can flow under the effect of a pressure gradient in a network of connected pores. Porous materials can be natural, such as soil and rocks, or synthetic, such as a densified network of fibres or open-cell foams. The measurement of permeability is diffic...

Permeability is a fundamental property of porous media, especially when studying resin transfer within a dense fibrous medium to manufacture composite materials. When the measurement of permeability tensor of composite reinforcements is difficult and time consuming, especially in thick, heterogeneous fibrous structures, a numerical approach based o...

A numerical model is proposed to simulate significant yarn slippage and unweaving in woven fabrics using the Arbitrary Lagrangian Eulerian (ALE) method. Woven fabrics were modeled at the yarn scale using 1D ALE elements with additional slip displacement degrees of freedom (DOF). The relatively weak bending stiffness of the yarn was included using a...

The consideration and implementation of actions to reduce the environmental footprint of products and sectors are becoming major concerns. Recycling wind turbine blades and induced production wastes are becoming significant challenges due to the nature of the currently used materials, i.e., fiber-reinforced thermoset polymer composites, making it c...

Environmental impact is becoming increasingly important in the automotive industry, with car manufacturers looking to reduce CO 2 emissions through cleaner engines and structural weight reduction. Composite materials offer an excellent alternative to standard steels with significant weight reduction and the ability to produce functional parts (Rang...

The main idea behind “Quilted Stratum Process” (QSP ® ) is to create a flat blank made of unidirectional/woven thermoplastic prepreg patches instead of using uniformly shaped prepreg stack as is the case with standard thermostamping process. Thus, using QSP ® ; one can manufacture components with complex geometries by using nearly rectangular patch...

Permeability measurements of engineering textiles exhibit large variability as no standardization method currently exists; numerical permeability prediction is thus an attractive alternative. It has all advantages of virtual material characterization, including the possibility to study the impact of material variability and small-scale parameters....

In the context of environmental transition, the environmental impact of composite parts manufacturing has to be improved as well as the impact of each step of the life cycle. However, a lack of data makes this improvement difficult as few studies have focused on the environmental impact of the manufacturing process of composite parts by giving deta...

The Zero wastE Blade ReseArch project (ZEBRA), led by the French technical research center IRT Jules Verne, is looking to accelerate the industry transition to circular economy by designing and manufacturing the first 100% recyclable wind blades, using the thermoplastic resin ELIUM®, developed by Arkema. To improve the infusion process, the objecti...

In the Resin Transfer Molding (RTM) process, a polymeric resin is injected inside a dry preform to fill the gaps around and inside the fiber tows. Simulating this process at the scale of the tows is challenging because of the computational cost associated to solving a three-dimensional dual-scale flow problem. In this work, a novel Dual-Scale Skele...

Tailored Fibre Placement (TFP) allows manufacturing net shape preforms with continuously varying orientations and thickness. This additive technology, combined with forming, enables the design of fiber reinforced composite parts with optimized fiber orientations. A new modelling strategy to simulate the forming of thin dry TFP preform without backi...

This paper presents a new methodology to extend the Data-Driven Identification (DDI) to heterogeneous samples made of multiple elastic materials. By using the Correspondence Analysis (CA) technique to post-process DDI, we are able to identify multiple material databases representative of the material behavior of each phase. Simultaneously, we local...

In this article, we provide a general description of a random stack of solid particles. We consider fine particles of any shape distributed evenly on a flat surface. The angular distribution of the particles is arbitrary. In the absence of constraints imposed on the medium, the volume fraction is expressed analytically according to the parameters o...

For fast and complete impregnation in Liquid Composite Molding, knowledge about the permeability of the fibrous reinforcement is required. While development of experimental methods continues, a parallel benchmark effort to numerically characterize permeability is being pursued. The approach was to send out the images of a real fibrous microstructur...

In the frame of LCM processes, the mesoscopic architecture of a preform is defined by the sequential stacking of layers in the mold. Once the compaction is carried out, the precise orientation of layers and spatial distribution of tows is difficult to know with precision. The lack of this information can lead to a wrong prediction of properties. In...

One can compute the final deformation of a known geometry under specific boundary conditions using the constitutive laws of mechanics that describe their stress strain behavior. In such cases the initial geometry is known, and all operators mapping the deformation are defined on the reference domain. However, there are situations in which the final...

Fibrous textiles are subjected to dry through-thickness compaction during most of the composites manufacturing processes. Usual tow models implemented in textile numerical simulations do not reproduce the tow widening occurring during the compaction. Nonetheless, this widening (that can reach 10%) would influence the internal microstructure of the...

“Quilted Stratum Process” (QSP ®) is a new process in the category of thermoplastic composite forming with the objective to locally strengthen the composite parts by strategically stacking discontinuous UD/woven prepregs while maintaining the short cycle time of about 1 min. Interply adhesion arising due to polymer tack plays an important role in Q...

Continuous fiber-reinforced thermoplastic composites can be produced by compression or consolidation processes at a temperature above the thermoplastic melting temperature. High production rates or high fluidity thermoplastic (TP-HF) viscosities can lead to large in-plane displacements of the fibrous network during the process. The same mechanisms...

“Quilted Stratum Process” (QSP®) is a new process developed by CETIM, Ecole Centrale de Nantes and their partners which is in the category of thermoplastic composite forming. Unlike the conventional thermoforming process, a QSP® preform stack consists of several discontinuous plies. Due to the inability of using the blank-holders in this process, t...

The mechanical efficiency of fiber-reinforced composite materials mainly depends on the alignment of fibers along the load paths arising from the boundary conditions applied to the part. On this basis, the Tailored Fiber Placement (TFP) consists in building a fibrous reinforcement by continuously laying down a tow on a plane backing material which...

Macroscopic properties of composites are highly dependent on the properties and distribution of fibers. Thus, knowing the distribution of fiber orientations is necessary to predict the mechanical performance of the final part. Various image processing techniques have been developed for the quantification of fiber orientations from optical microscop...

Quilted Stratum Process" (QSP ®) is a unique thermoplastic composite forming process which locally strengthens the composite parts by strategically stacking discontinuous UD/woven prepregs. Interply adhesion is important in QSP ® because of resin-rich layer at ply-ply interfaces, inability to use blank holders and high temperature where the resin i...

The 19th European Conference on Composite Materials (ECCM19) will be be held in Nantes, France between June 22-26, 2020. ECCM provides a forum for accessing to the most up-to-date knowledge from both industrial and academic worlds in all the fields of Composite Materials. The meeting will provide an opportunity to highlight latest developments and...

A method to identify the strain-stress relations of materials based on the data-driven computational mechanics paradigm was proposed by Leygue et al. (2018), which waives the need of any underlying constitutive equation. Given a strain field, the algorithm solves a minimization problem constrained to equilibrium and compatibility conditions in orde...

Le procédé QSP ® est un procédé de formage d'une préforme composite thermoplastique optimisée constituée de patchs préimprégnés unidirectionnels et tissés discontinus. Les patchs sont découpés de façon à limiter les chutes, puis sont distribués stratégiquement dans la préforme à plat, chauffés et formés rapidement pour atteindre un temps de cycle c...

During compression of saturated fibrous reinforcement, the flow of the liquid can, under certain conditions, generate fiber-tows washout (in-plane movement of fiber-tows) due to the strong hydrodynamically induced force on the fibrous reinforcement. The objective of the study is first to detect experimentally the onset and measure the full-field ma...

Tows, partially constrained (tows within textile architecture) or free (single tows) exhibit movements and deformations, due to the various mechanical solicitations applied during manufacturing. During weaving or stitching, single dry tows undergo local compaction due to interlacing or stitch, leading to the evolution of the tows cross-section whil...

Composites manufacturing using the infusion process involves an unloading phenomenon due to the vacuum bag flexibility. Additionally, during impregnation, woven or non-crimp fabrics exhibit a dual-scale flow. Usual modeling of both phenomena assumes that the fibrous preform is a continuous medium with a varying permeability. Nonetheless, the permea...

In Liquid Composite Molding (LCM) processes, fabric layers are stacked in a mold which may be a few meters long and wide to build up a thickness of not more than a few millimeters. Resin is introduced to fill all the empty spaces between the fibers. As the in plane dimensions are a few orders of magnitude larger than through the thickness, flow of...

This paper addresses the complexity reduction of stochastic homogenisation of a class of random materials for a stationary diffusion equation. A cost-efficient approximation of the correctors is built using a method designed to exploit quasi-periodicity. Accuracy and cost reduction are investigated for local perturbations or small transformations o...

Consolidation is a crucial step in manufacturing of composite parts with prepregs because its role is to eliminate inter- and intra-ply gaps and porosity. Some thermoset prepreg systems are toughened with thermoplastic particles. Depending on their size, thermoplastic particles can be either located in between plies or distributed within the inter-...

Fibrous fabrics are used in a variety of applications, among them, for structural composites. Most fabrics are efficiently manufactured from tows or yarns. During textile manufacturing or during fiber reinforced composites manufacturing, the fabrics and tows undergo several movements and deformations. Although there have been several attempts by di...

The aim of this work is to investigate the viscoelastic effect during acoustoelastic testing of a thermoplastic (polyethylene) for a reliable stress evaluation, which is critical for the processing and in-service life of thermoplastic products. The strain accumulated under step loading-holding stages was firstly characterized by a stepped isostress...

In this study, a simplified cost effective simulation-based methodology is proposed to assist manufacturing engineers in the design and development phase of the resin transfer molding process. Race-tracking is unavoidable in the resin transfer molding and can lead to entrapment of air pockets, which results in parts being discarded as scrap. A pure...

JEC Composites Magazine Issue 120, April 2018 Composite manufacturing still often relies on trial-and-error approaches to design the process, making little use of the plethora of science-based literature, models and simulations. This paper presents an approach for the development of easy-to-use tools with no learning curve, with lower licensing co...

Composite manufacturing still often relies on trial-and-error approaches to design the process, making little use of the plethora of science-based literature, models and simulations. This paper presents an approach for the development of easy-to-use tools with no learning curve, with lower licensing costs and can provide useful information to manuf...

Thermoplastic matrix composites reinforced with glass fiber reinforcements are viewed as an alternative to thermoset matrix composites for structural components in the automotive field, as they allow for lower costs and higher production rates. However, the forming of thermoplastic composites from a preform made of discontinuous plies is more sensi...

In the Vacuum Assisted Resin Transfer Molding (VARTM) process to manufacture composites, woven or stitched fabrics are stacked on top of a tool surface and resin is introduced into this porous network by drawing a vacuum. For large parts, to reduce the time for filling, highly permeable distribution media (DM) is placed on top of the fabric layers...

Characterizing the response of compressed dry fibrous reinforcements is a key feature to control liquid composite molding processes. Considering preforms manufactured by automated dry fiber placement, supplementary information are needed, since cyclic loading occurs, during which the mechanical properties of tows evolve. In this way, an extensive c...

This paper proposes to address the issue of complexity reduction for the numerical simulation of multiscale media in a quasi-periodic setting. We consider a stationary elliptic diffusion equation defined on a domain $D$ such that $\overline{D}$ is the union of cells $\{\overline{D_i}\}_{i\in I}$ and we introduce a two-scale representation by identi...

This paper proposes to address the issue of complexity reduction for the numerical simulation of multiscale media in a quasi-periodic setting. We consider a stationary elliptic diffusion equation defined on a domain $D$ such that $\overline{D}$ is the union of cells $\{\overline{D_i}\}_{i\in I}$ and we introduce a two-scale representation by identi...

The freedom of composite design can be improved by combining continuous and discontinuous prepregs. The forming of a pre-heated blank made of optimally oriented and distributed discontinuous prepreg plies may lead to unacceptable defects such as in-plane and out-of-plane wrinkles, sliding of plies over long distance, rotation of adjacent plies, ben...

Several studies showed that thin-plies composite laminates apparently exhibit higher strength than its counterpart using thicker plies. In this work, a high-resolution numerical discretization based on the use of in-plane-out-of-plane separated representations within the Proper Generalized Decomposition – PGD – framework is performed in different c...

Composites manufacturing processes usually involve multi-scale models in both space and time, highly non-linear and anisotropic behaviors, strongly coupled multi-physics and complex geometries [1]. In this framework, the use of simulation for real-time decision making directly in the manufacturing facility is still precluded nowadays [2]. In this w...

The fundamental macroscopic material property needed to quantify the flow in a fibrous medium viewed as a porous medium is the permeability. Composite processing models require the permeability as input data to predict flow patterns and pressure fields. As permeability reflects both the magnitude and anisotropy of the fluid/fiber resistance, effici...

Fibrous composite reinforcements with enhanced permeability are of a particular interest for liquid composite molding processes requiring the fibrous preforms to be well impregnated by a viscous polymer. The aim of this work is to study the link between the reinforcement permeability and the geometrical parameters of its architecture, taking into a...

Bottom ash resulting from the incineration of various domestic wastes can be viewed as a typical granular material. It is mainly used in civil engineering as a substitute for traditional natural aggregates. The purpose of this paper is to characterize their mechanical behavior and evaluate their mechanical properties for engineering applications. F...

Thermoplastic matrix composites reinforced with glass fiber reinforcements are viewed as an alternative to thermoset matrix composites for structural components in the automotive field, as they allow for lower costs and higher production rates. However, the forming of thermoplastic composites from a preform made of discontinuous plies is more sensi...

Composites manufacturing processes usually involve multiscale models in both space and time, highly non-linear and anisotropic behaviors, strongly coupled multiphysics and complex geometries. In this framework, the use of simulation for real-time decision making directly in the manufacturing facility is still precluded nowadays, in spite of the imp...

This work addresses the numerical simulation of compression moulding of Sheet Moulding Compound (SMC) where the behaviour of the polymer is supposed Newtonian and thermal effects are neglected. The proposed model relies on the Stokes formulation combined with Lubrication Theory, following the approach developed in [2]. It is solved using a Finite E...

A crucial step in many composites manufacturing processes is the impregnation of fibrous medium with the resin. The fundamental property needed to quantify the flow is the permeability of the fibrous medium. Process models require the permeability as input data to predict flow patterns and pressure fields. Efficient numerical techniques are needed...

In this paper a model of Transversely Isotropic Fluid (TIF), developed by Pipkin in [1], is presented and used for example to model in 2D the in-plane shearing of UD prepreg. This problem demonstrates the need to have a continuous fiber tension field over the elements, with the final objective of detecting the wrinkling of fibers during the forming...

Thermoplastic composites are attractive because they can be recycled and exhibit superior mechanical properties. The ability of thermoplastic resin to melt and solidify allows for fast and cost-effective manufacturing processes, which is a crucial property for high volume production. Thermoplastic composite parts are usually obtained by stacking se...

This research addresses the effects of quasi-UD non-crimp fabric (NCF) design parameters on the fabric architecture and on the permeability tensor. These fabrics are designed for the Liquid Resin Infusion (LRI) of large and thick composite parts. Three fabrics’ parameters intended to bring a flow enhancement to the NCF are investigated: the stitch...

Coda wave interferometry (CWI) is largely employed in geotechnical applications to monitor changes due to cracks in materials but it is still not used for composite materials. In this paper, the technique is proposed to study internal stresses in a composite laminate [0°/90°]63 and was compared with the traditional acoustic technique. It is shown t...

Image-based simulation is becoming an appealing technique to homogenize properties of real microstructures of heterogeneous materials. However fast computation techniques are needed to take decisions in a limited time-scale. Techniques based on standard computational homogenization are seriously compromised by the real-time constraint. The combinat...

Ensuring a good inter-laminar bonding while accelerating the production in the tape winding process of thermoplastic tapes is a key question. Finite element models and numerical simulation help to predict the influence of process parameters on the product quality. This article addresses the finite element modeling of the thermal and mechanical phen...

MSWI) can be viewed as a typical granular material because these industrial by-products result from the incineration of various domestic wastes. MSWI bottom ash is mainly used in road engineering in substitution of the traditional natural aggregates. As the characterization of their mechanical behavior is essential in order to use them, specific st...

Most Out-of-Autoclave prepregs (OoA) are only partially impregnated with resin. Their impregnation completes during the cure cycle, solely driven by the difference between atmospheric and vacuum pressure. Increased part length leads to an impregnation time gradient caused by the transient air flow inside the fibrous medium. In this work, a novel nu...

The construction of mesoscopic models of fiber washing effects during the high pressure resin transfer molding (RTM) process with thermoplastic polymers requires the knowledge of the limit of adhesion coefficients between dry and impregnated fabric reinforcement plies and the mold. To measure these coefficients, a new method is described. During RT...

Three different types of a quasi-unidirectional fabric have been produced and studied in order to reach the objective of the enhanced longitudinal permeability. The overall goal of the project TAPAS is to use the optimised fabric in a RTM process adapted to high fluidity polyamide 6,6. Microstructure study is undertaken with Scanning Electron Micro...

The acoustic birefringence method has been used since a long time for metallic materials to detect residual stresses. This method is rarely used for polymers and composites due to the strong attenuation of the acoustic signal. Moreover, for thermoplastic polymer, with a slight anisotropy (known as texture for metals), coupling with applied stresses...

This paper provides a methodology for the modeling of heat transfer and polymer flow during direct thermoplastic injection pultrusion process. Pultrusion was initially developed with thermosets which have low viscosity. But the impregnation becomes a critical point with thermoplastics which exhibit higher viscosity. There are very few reported work...

The necessity to realize a mechanical study of tows at the fiber-scale comes from the fact that the quality of composite parts depends on spatial distribution of fibers and fiber-fiber interactions during automated placement. This paper presents the 3-D dynamic modeling of one fiber motion with an articulated bodies system. Complex shape composite...

The motion of an ellipsoidal particle immersed in a Newtonian fluid was studied in the pioneering work of Jeffery in 1922. Suspensions of industrial interest usually involve particles with a variety of shapes. Moreover, suspensions composed of rods (a limit case of an ellipsoid) aggregate, leading to clusters with particular shapes that exhibit, wh...

The flow of polymeric fluids in complex geometries relevant to processing applications can be simulated numerically using a wide variety of theoretical models. Simple mathematical models have a purely macroscopic nature and focus only on the non-linear relationship between shear viscosity and shear rate. More advanced models address the viscoelasti...

Continuous fiber reinforced polymer (CFRP) always involves a fluid flow through the fibrous medium, whether to create a semi-product like a prepreg that will be further processed to make the final part or to directly manufacture a part from dry fiber reinforcement. This chapter discusses the physics and modeling of flow of simple fluids within comp...

A crucial step in many composites manufacturing processes is the impregnation of fibrous medium with the resin. The fundamental property needed to quantify the flow is the permeability of the fibrous medium. Process models require the permeability as input data to predict flow patterns and pressure fields. Image-based computation can offer a good a...

Image-based simulation is being considered more and more in industrial applications, where more than simulate the expected reality it seems preferable to simulate the reality itself. For example, in heterogeneous composite materials more than assuming a particular distribution of the material constituents, it is preferable to solve the model in the...

The aim of this work is to investigate the acoustoelastic effect in a thermoplastic polymer (polyamide 6) under uniaxial compression using ultrasonic waves (longitudinal and shear). The acoustic velocities varied linearly, as expected, when small strains or stresses were applied, from which Murnaghan coefficients were obtained for the first time fo...

A new dynamic method based on bilayer system is proposed to characterize the residual stress formation during the crystallization of semi-crystalline polyethylene glycol 10000 (PEG10000). The resin is coated on a solid polymeric film to create a filmsubstrate compound. Its temperature field and dynamic deflection are monitored by synchronized optic...