Arthur Cantarel

Metal matrix composite processing: numerical study of heat transfer between fibers and metal

Purpose – To study heat transfer kinetics at the fiber scale in order to describe injection of liquid metal through a fibrous perform initially situated in a preheated mould, which is one of the various methods used in order to produce metal matrix composite materials (MMCs).Design/methodology/approach – The first part presents a preliminary study in a static case to describe heat transfer kinetics between a fiber and the matrix in the case of a sudden contact of both components initially set up at different temperatures. This model enables to study the influence of the various parameters of the problem on heat transfer kinetics with phase change. In the second part, we present a modeling which takes into account the metal convection within the pores of the preform.Findings – The numerical results of these two models justify the instantaneous thermal equilibrium assumption classically admitted to describe MMCs manufacturing methods. The results of this dynamic microscopic model are compared with the resul...

Mold Filling Simulation of Resin Transfer Molding Combining BEM and Level Set Method

Liquid Composite Molding (LCM) is a popular manufacturing process used in many industries. In Resin Transfer Molding (RTM), the liquid resin flows through the fibrous preform placed in a mold. Numerical simulation of the filling stage is a useful tool in mold design. In this paper the implemented method is based on coupling a Boundary Element Method (BEM) with a Level Set tracking. The present contribution is a two-dimensional approach, decoupled from kinetics, thermal analysis and reinforcement deformation occurring during the flow. Applications are presented and tested, including a flow close to industrial conditions.

Numerical Simulation of Segregation Phenomena Coupled with Phase Change and Fluid Flow: Application to Metal Matrix Composites Processing

The injection of a liquid metal through a fibrous preform, located in an initially preheated mold, is one of the techniques used to manufacture metal matrix composites (MMCs). In order to reduce the chemical reactions between the fibers and the metal matrix, the fibrous reinforcement and the mold are commonly preheated up to initial temperatures much lower than the metal solidification temperature. Therefore, local metal solidification instantaneously occurs on fiber during liquid metal infiltration. When infiltrating metal alloy, unlike what happens when infiltrating a pure metal, both temperature and composition may vary within the matrix; this heterogeneity induces segregation within composites. A fiber scale numerical simulation was developed taking into account coupled physical phenomena which occur during the processing: flow of the liquid metal around the fibers, phase change phenomena, solute redistribution at the liquid/solid interface during alloy solidification, and species diffusion. This model predicts the segregation phenomena associated with fibrous preform infiltration by a binary alloy.

Toward improvement of the properties of parts manufactured by FFF (fused filament fabrication) through understanding the influence of temperature and rheological behaviour on the coalescence phenomenon

In this paper, the printing temperature ranges of PLA and PEEK, two semi-crystalline thermoplastics, have been investigated for the Fused Filament Fabrication (FFF) process. The printing range, comprised between the melting temperature and the degradation of each polymer, is 160°C to 190°C for PLA and 350°C to 390°C for PEEK. The complex viscosity has been measured for both polymers within the printing range. The kinetics of coalescence has been registered by measuring the bonding length between two filaments of the same polymer according to the temperature. At 167°C, the filaments of PLA reached the maximum value of bonding length. For PEEK, the filaments reached the maximum value of bonding length at 380°C. For the both materials, the final height of the filament is 80% of the initial diameter. The comparison of the obtained results with experimental study and predictive model shows a good agreement when the polymer is totally in fusion state.

Bonded repair issues for composites: An investigation approach based on infrared thermography

An original approach based on active Infrared Thermography (IT) addresses the very challenging issue of the nondestructive analysis of bonded repaired CFRP laminates. Difficulties come from the weak property contrast between parts of repaired assemblies and thickness of the joint. Strong attention is given here to the control of experimental tests conditions (heat load, boundary conditions), which allows to develop a physically consistent numerical model of the thermal problem. Comparison between measured and simulated surface temperature fields shows very good agreement regarding temporal and spatial evolutions for composites with different lay-up and offers new solutions for the NonDestructive Testing (NDT) of bonded repaired composites.

Thermographic investigation of heat source in transversely isotropic composites

This paper deals with the estimation of heat sources from infrared thermographic measures on anisotropic CFRP (Carbon-Fibre Reinforced Composites). Such procedure combines the data processing of the thermal signal, especially as spatial and temporal derivation quantities involved in the heat equation are notably affected by the measurement noise, and the determination of thermo-physical properties of the material, especially to account for the anisotropic conductivity behavior of the material. A comparative analysis of different filtering techniques is done to define a filtering method able to decrease the noise while keeping the useful features of the signal. Then, we use a homogenization scheme based on single-inhomogeneity solutions of Eshelby to derive the transversely isotropic thermal conductivity tensor.

Influence of structural parameters at microscale on the fiber reinforcement

In this paper, a random configuration model for fiber arrangement is proposed and implemented in a computer code. This development enables the investigation of the effect of the random arrangements of the fibers inside the tow on the permeability and the flow properties. Four parameters are considered including three microstructural parameters: side length of the domain L, variation of radii Δr, minimum interfiber distance δmin, and one macro parameter: porosity ɛ. Finite element method is performed for the transverse flow of porous media with random arrangements of fibers. Morris method for global sensitivity analysis is used to study the influence of four parameters. The results have shown that the porosity ɛ has the most obvious influence on the fiber reinforcement permeability.

BEM Simulation of 3D Updated Resin Front for LCM Processes

The use of composite materials in large structures has increased in recent years. Aircraft industry has recently begun to investigate the field of Liquid Composite Molding (LCM) through research programs because of its ability to produce large parts at low cost. The present paper focuses on modeling a 3D radial impregnation through an anisotropic fibrous perform. As a preliminary work, it is assumed an isothermal flow and no hydro-mechanical coupling. Governing equations are Darcy’s law and mass conservation. Simulation is performed combining Boundary Element Method (BEM) with a lagrangian moving mesh method. An analytical solution is developed to assess the numerical model.