Publications by Véronique Michaud

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Translaminar fracture toughness is pivotal for notch sensitivity and damage tolerance of fibre-reinforced composites. Hybridisation offers a promising pathway for enhancing this parameter in thin-ply composites. Three novel mini-compact tension specimen ge ...

This paper reports the results of an international benchmark exercise on the measurement of fibre bed compaction behaviour. The aim was to identify aspects of the test method critical to obtain reliable results and to arrive at a recommended test procedure ...

In many cases of composite processing by liquid matrix impregnation, the fiber reinforcement is compressed when it comes in contact with the liquid and then relaxes as the matrix flows within its pores. This phenomenon can be analyzed in terms of local fluid flow, mass conservation and mechanical equilibrium. A model is proposed to simulate the kinetics of impregnation, and the evolution of the fiber volume fraction profile as the resin front progresses, as well as after the front has reached the end of the

In this second international permeability benchmark, the in-plane permeability values of a carbon fabric were studied by twelve research groups worldwide. One participant also investigated the deformation of the tested carbon fabric. The aim of this work w ...

During cure of epoxy resins, polymerization induces an increase in mechanical properties, which is accompanied by a volumetric shrinkage. When the resin is cured in a constrained mold to which it adheres, tensile stresses will hence develop, which may exceed the strength of the resin at a given curing stage. Voids will then form. The origin and governing parameters of void formation are studied using an epoxy resin cured in a three-dimensionally constrained glass mold following isothermal cure cycles. Two t

The different steps associated with the curing of a PVAc/polyester blend are identified and correlated to the mechanism of shrinkage control in the presence of a low-profile additive (LPA). Poly(vinyl acetate) (PVAc) is used as a LPA and is shown to induce ...

Frontal polymerisation has the potential to bring unprecedented reductions in energy demand and process time to produce fibre reinforced polymer composites. Production of epoxy-based fibre reinforced polymer parts with high fibre volume content, commonly e ...

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 ...

An experimental method based on a falling pressure measurement is proposed to evaluate the through thickness air permeability of prepregs during cure, with two set-up variants. One concerns the measurement of the inherent air permeability and the other app ...

The curing reaction of an epoxy resin [diglycidyl ether of bisphenol A (DGEBA)] combined with a methyl-hexahydrophtalic anhydride (MHHPA) hardener and a benzyldimethylamine (BDMA) accelerator was studied over a temperature range of 60 140°C to build its isothermal time-temperature-transformation (TTT) cure diagram. This includes gelation and vitrification measurements using rheological measurement techniques, monitoring of the glass transition temperature and the reaction kinetics by differential scanning c

Carbon fiber-reinforced polymers are increasingly employed in load-bearing structures such as thick reservoirs, pipes or flywheels where cure-induced defects can impair performance and dimensional accuracy. This study investigates whether interlaminar performance and microstructure quality are preserved in tow-wound composites fabricated via partial pre-curing and in situ compaction, which proved to mitigate the risk of thermal overshoot and stress build-up. A proof-of-concept manufacturing line is develope

This paper sets out to review the current state of the art in applying self-healing/self-repair to high-performing advanced fiber-reinforced polymer composite materials (FRPs). A significant proportion of self-healing studies have focused so far on develop ...

The cost-effective production of high-performance and durable steel reinforced thermoplastic composites requires improvement of the adhesion encountered at the interface between metallic substrates (galvanized steel) and a thermoplastic elastomer (TPU). Combined requirements of processing speed, adhesion and durability were assessed by using cationic photo-polymerized coatings at the TPU-metal interface. The adhesion was studied by pull-out tests on co-molded TPU matrix - galvanized steel wires samples befo

Thermoplastic compression resin transfer moulding coupled with injection moulding is an appealing process for the production of thermoplastic composites. However, its implementation at an industrial scale remains challenging as variotherm injection mouldin ...

Permeability is defined here from the equations of fluid flow through porous media. It represents, for composite reinforcements, a measure for their ease of impregnation by a fluid resin. Modeling of the saturated permeability tensor is presented using a h ...

A new model is proposed for the consolidation of hybrid textiles, in which air entrapment and dissolution are considered. One of the key parameters is tow permeability, which is described by the analytical model of Gebart and validated at very high fibre v ...

We report the first measurements of a self-healing polymer that combines a microencapsulated liquid healing agent and shape memory alloy (SMA) wires. When a propagating crack ruptures the embedded microcapsules, the liquid healing agent is automatically re ...

In the impregnation process, when pressure is applied, the dry fiber preform is first compressed and then unloads as the matrix flows within the pores. It has been shown earlier that for glass mat-reinforced thermoplastic (GMT) materials, the time to provi ...

The development of internal stress during cure of epoxy and hyperbranched polymer- modified epoxy resins was characterized, taking into account the evolving viscoelastic properties, the volumetric shrinkage due to the chemical reaction, and the thermal expansion. A criterion for void formation during cure in a constrained mold was proposed, providing guidelines for the construction of a process window for manufacturing of void-free composites. It was shown that the internal stress development in epoxy resin

A study of the microstructure developing at the surface of glass fibers in a poly(vinyl acetate) (PVAc)/polyester blend is presented. Three different experimental methods are used: a technique based on the Wilhelmy method to measure the wettability of the ...

Véronique Michaud

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Translaminar fracture in (non–)hybrid thin-ply fibre-reinforced composites: An in-depth examination through a novel mini-compact tension specimen compatible with microscale 4D computed tomography

Experimental characterisation of textile compaction response: A benchmark exercise

Impregnation of compressible fiber mats with a thermoplastic resin, Part I: Theory

Experimental determination of the permeability of engineering textiles: Benchmark II

Stress-initiated void formation during cure of a three-dimensionally constrained thermoset resin

Low-Profile mechanisms in a PVAc/polyester blend

Self-catalysed frontal polymerisation enables fast and low-energy processing of fibre reinforced polymer composites

A new ISO standard for the experimental characterization of in-plane permeability of fibrous reinforcements

Through thickness air permeability of prepregs during cure

TTT - Cure diagram of an anhydride-cured epoxy system including gelation, vitrification, curing kinetics model and monitoring of the glass transition temperature

Feasibility of tow winding with partial pre-curing and in situ consolidation for curved composite laminates

Progress in Self-Healing Fiber-Reinforced Polymer Composites

Fast-curing coatings for adhesion promotion between metallic oxides and thermoplastic polyurethane

Novel tooling for direct melt impregnation of textile with variotherm injection moulding: Methodology and proof of concept

Permeability properties of composite reinforcements

A model for the consolidation of hybrid textiles considering air entrapment, dissolution and diffusion

Performance of self-healing epoxy with microencapsulated healing agent and shape memory alloy wires

Graded glass mat reinforced polypropylene

Internal Stress Control in Epoxy Resins and their Composites by Material and Process Tailoring

Phase separation at the fiber-matrix interface in composites based on a thermoplastic/polyester blend