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Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Effet pression, Pressure effect, Efecto presión, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode empilement, Stacking sequence, Modo apilamiento, Modèle 3 dimensions, Three dimensional model, Modelo 3 dimensiones, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Résistance compression, Compressive strength, Resistencia compresión, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, Matériau fibre multidirectionnelle, WWFE-II, benchmark data, hydrostatic pressure, through-thickness, and triaxial

This article describes a unique set of experimental results employed in benchmarking leading three-dimensional failure criteria, as a part of the Second World Wide Failure Exercise (WWFE-II). In Part A of WWFE-II, the originators of those criteria (or their representative) made blind theoretical predictions of the triaxial strength, stress―strain curves and deformation of 12 Test Cases, selected by the organisers to challenge the contributors' models. The cases covered various materials and laminates subjected to a wide range of triaxial and through-thickness loading conditions. The Test Cases were for (a) an isotropic material made of an epoxy polymer, (b) various 0° unidirectional laminae and (c) (0°/90°)s, (0°/±45°/90°)s and (±35°)s multi-directional laminates. In Part B of WWFE-II, a comparison is made by the contributors between available experimental results, described here, and their theoretical predictions, made in Part A. Discussion is also made on the accuracy of these results.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Divers, Miscellaneous, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Argent, Silver, Plata, Batterie, Battery, Batería, Carbone, Carbon, Carbono, Cathode, Cátodo, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Etude expérimentale, Experimental study, Estudio experimental, Matériau revêtement, Coating material, Material revestimiento, Matériau électrode, Electrode material, Material electrodo, Multicouche, Multiple layer, Capa múltiple, Oxygène, Oxygen, Oxígeno, Polymère aromatique, Aromatic polymer, Polímero aromático, Polymère conducteur, Conducting polymers, Pyrrole polymère, Pyrrole polymer, Pirrol polímero, Réaction électrochimique, Electrochemical reaction, Reacción electroquímica, Réduction chimique, Chemical reduction, Reducción química, Batterie métal air, Metal air battery, composite electrode, conductive polymer, electrodeposition, and silver

A novel three-component composite electrode consisting of a carbon current collector with conductive polymer and silver coating is described here. The composite electrode fabrication strategy is described and the composite electrode is evaluated as a cathode for oxygen reduction in non-aqueous media. This approach is utilized for the first time to prepare three-dimensionally structured carbon―conductive polymer―silver composites, yielding composite electrodes with ∼4× the oxygen reduction capacity of their planar counterparts. Improvement of cathode oxygen reduction activity will increase current capability and power output of metal air batteries, facilitating future development of small, lightweight, and long-life power sources.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Charge complexe, Complex load, Carga compleja, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode rupture, Fracture mode, Modo ruptura, Modèle non linéaire, Non linear model, Modelo no lineal, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résistance compression, Compressive strength, Resistencia compresión, Résistance flexion, Bending strength, Resistencia flexión, Résistance traction, Tensile strength, Resistencia tracción, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Matériau fibre multidirectionnelle, Stratifié croisé, Dispersed micro-damages, bending, failure envelopes, open hole, and strength

This article presents a model, known as generalized Daniels' model, describing the process of micro-damage accumulation, deformation and failure of multilayered fibre reinforced composite structures under complex internal states of stress responding to external plane-stress loading. The model considers three independent kinds of ply micro-damage: longitudinal, transverse and shear. Non-linear analysis, taking into account scissoring effects, is used to make theoretical predictions for all the 13 test cases involved in the third world-wide failure exercise. The cases cover the biaxial failure behaviour of a unidirectional and multi-directional laminates, failure of thick and thin cross ply and quasi-isotropic laminates under tension, damage due to thermal loading, bending of a general laminate, loading and re-loading and the predictions of the tensile and compressive strength values of test specimens with an open hole. For the prediction of notched strength of laminates with hole, the model is used with a non-local approach based on the specific size of ply microstructure and Neuber's hyperbola of specific deformation energy. The results are presented for all the 13 test cases.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Critère rupture, Fracture criterion, Criterio ruptura, Délaminage, Delamination, Delaminación, Effet dimensionnel, Size effect, Efecto dimensional, Endommagement, Damaging, Deterioración, Etude comparative, Comparative study, Estudio comparativo, Etude théorique, Theoretical study, Estudio teórico, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode empilement, Stacking sequence, Modo apilamiento, Mode rupture, Fracture mode, Modo ruptura, Modélisation, Modeling, Modelización, Rupture matrice, Matrix fracture, Ruptura matriz, Stratifié, Laminate, Estratificado, Damage, bending, delamination, failure envelope, matrix cracking, open hole, and third world-wide failure exercise

The authors have recently completed two world-wide failure exercises, which dealt with benchmarking recognised failure criteria under two-dimensional and three-dimensional loadings, respectively. A new phase, called the 'third world-wide failure exercise' is currently underway to fill some of the major gaps identified in the previous activities. The third world-wide failure exercise is concerned with highlighting the degree of maturity of the current capabilities of 12 internationally recognised methods for modelling various aspects of damage in composite materials. Such problems include matrix cracks due to thermal and mechanical loads; delamination; ply constraint and stacking sequence effects; loading and unloading phenomena; failure due to stress gradients (in particular the hole size effect). The topics addressed within the third world-wide failure exercise represent an extremely important and crucial area for advanced modelling and virtual testing of composites. The third world-wide failure exercise runs in two stages (1) Part A which is devoted to providing full details and a comparison between the 12 theories together with their 'blind' predictions, made by their originators, for a challenging set of test problems and (2) Part B which is concerned with comparing the theoretical predictions with experimental results and assessing the accuracy and maturity of the methods. This paper provides details of the background to third world-wide failure exercise, the process of completing Part A and a summary of key conclusions.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Effet pression, Pressure effect, Efecto presión, Etude théorique, Theoretical study, Estudio teórico, Matériau composite, Composite material, Material compuesto, Modèle 3 dimensions, Three dimensional model, Modelo 3 dimensiones, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Polymère, Polymer, Polímero, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Résistance compression, Compressive strength, Resistencia compresión, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Second World-Wide Failure Exercise, benchmark, failure, polymeric composite, pressure, three-dimensional stress, and triaxial

The Second World-Wide Failure Exercise was launched and organised by the authors to determine the accuracy of current theories for predicting failure in polymer composite laminates under three-dimensional states of stress. This paper provides an introduction to the second stage ('Part B') of Second World-Wide Failure Exercise within which the level of maturity and accuracy of the leading three-dimensional failure theories for composites are assessed against experimental data, their strengths and weaknesses are identified and conclusions are drawn. The Second World-Wide Failure Exercise builds upon the process and philosophy developed during the First World-Wide Failure Exercise with the clear aims of ensuring that the assessment is objective, transparent and an effective, accessible benchmark for use by the composites community.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Etude théorique, Theoretical study, Estudio teórico, Interface fibre matrice, Matrix fiber interface, Interfase fibra matriz, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Micromécanique, Micromechanics, Modèle 3 dimensions, Three dimensional model, Modelo 3 dimensiones, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Rupture fibre, Fibre fracture, Ruptura fibra, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Résistance compression, Compressive strength, Resistencia compresión, Résistance traction, Tensile strength, Resistencia tracción, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, Micromechanics of failure, damage, failure criterion, nonlinear, and strength

The research presented in this article is a continuation of the authors' work in Part A of the second world-wide failure exercise (WWFE-II). In Part A, a constituent damage model based on micromechanics of failure was employed in order to predict the failure envelopes and stress―strain curves for unidirectional and laminated composites under multi-axial loadings. In this study, original predictions were compared with experimental data, supplied in Part B of the second world-wide failure exercise. Three modifications were made to the previous model: (a) a quadratic fiber failure criterion was proposed to replace the maximum longitudinal stress failure criterion used for fibers in the original model; (b) a three-dimensional kinking model was introduced so as to take into account the influence of the formation of kinking bands on micro stresses in the matrix, when a ply is under longitudinal compression; and (c) in-plane shear terms in stress amplification factors were averaged to avoid overestimation of local stress concentration for regions within the matrix and in the vicinity of the fiber―matrix interface. Questions regarding the discrepancies between the idealized and actual tests were also raised and are discussed in this study.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte résiduelle, Residual stress, Tensión residual, Contrainte thermique, Thermal stress, Tensión térmica, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Durcissement (matière plastique), Curing (plastics), Endurecimiento (material plástico), Energie déformation, Strain energy, Energía deformación, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Tube, Tubo, Vérification expérimentale, Experimental test, Verificación experimental, 3D stresses, Strain energy criterion, failure envelope, and through-thickness

An analytical model to predict the constitutive response, failure initiation and post-initial failure behavior of fibrous composites under triaxial loading has been developed based on a strain energy formulation. This paper highlights the means of developing several key parameters in the model and extends the model to include the effects of in-plane thermal residual stresses accumulated during the curing of composite laminates. The derivations of a set of consistent model input parameters for several composite material systems are described. A series of comparative stress-strain curves and failure envelopes are provided comparing model predictions to published experimental data. The strain energy based failure model is found to provide good agreement with the experimental observations studied in this work.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques et équipements généraux, General equipment and techniques, Transducteurs, Transducers, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Vibration, onde mécanique, stabilité dynamique (aéroélasticité, contrôle vibration...), Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...), Aile, Wing, Ala, Cellule solaire, Solar cells, Conception pièce, Piece design, Concepción pieza, Contrôle vibration, Vibration control, Engin volant autonome, Unmanned aerial vehicle, Máquina autónoma voleando, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fibers, Matériau composite, Composite materials, Matériau stratifié, Layered materials, Modélisation, Modelling, Propriété électromécanique, Electromechanical properties, Propiedad electromecánica, Récupération énergie, Energy recovery, Transducteur piézoélectrique, Piezoelectric transducers, Gust alleviation, energy harvesting, multifunctional wing spar, piezoelectric material, and reduced energy control

This article examines the concept and design of a multifunctional composite sandwich structure for simultaneous energy harvesting and vibration control. The intention is to design a composite wing spar for a small unmanned aerial vehicle which is able to harvest energy itself from ambient vibrations during normal flight along with available sunlight. If the wing experiences any strong wind gust, it will sense the increased vibration levels and provide vibration control to maintain its stability. The proposed multifunctional composite wing spar integrates a flexible solar cell array, piezoelectric wafers, a thin film battery, and an electronic module into a composite sandwich structure. The piezoelectric wafers act as sensors, actuators, and harvesters. The basic design factors are discussed for a beam-like multifunctional wing spar with energy harvesting, strain sensing, and self-controlling functions. The configurations, locations, and operating modes of piezoelectric transducers are also discussed for optimal power generation. The equivalent electromechanical representations of a multifunctional wing spar is derived theoretically and simulated numerically. Special attention is given to the self-contained gust alleviation with the goal of using available energy harvested from ambient vibrations. A reduced energy control law is implemented to reduce the actuation energy and the dissipated heat. This law integrates saturation control with a positive strain feedback controller and is represented by a positive feedback operation amplifier and a voltage buffer operation amplifier for each mode. This study builds off of our previous research and holds promise for improving unmanned aerial vehicle performance in wind gusts. Here, we also include, but not use, a flexible solar panel in our modeling.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Charge multiaxiale, Multiaxial load, Carga multiaxial, Coefficient dilatation thermique, Thermal expansion coefficient, Coeficiente dilatación térmica, Critère rupture, Fracture criterion, Criterio ruptura, Délaminage, Delamination, Delaminación, Effet pression, Pressure effect, Efecto presión, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode rupture, Fracture mode, Modo ruptura, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété thermique, Thermal properties, Propiedad térmica, Propriété traction, Tensile property, Propiedad tracción, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Stratifié croisé, Plasticity, fracture energy, kink band, matrix cracks, propagation, and third World-Wide Failure Exercise

This paper showcases the authors' predictions for the 13 challenging test cases of the third World Wide Failure Exercise. The cases involve the prediction of lamina biaxial stress―strain curves, matrix cracking and delamination in various cross-ply and quasi-isotropic laminates under uniaxial loading, variation of thermal expansion coefficient of a laminate with matrix cracking, bending of a general laminate, loading-unloading behaviour and the strength of various thin and thick laminates containing an open hole. The laminates were made of various glass and carbon fibre/epoxy materials. The constitutive model is based on plasticity theory, includes hydrostatic pressure effects and accounts for multiaxial load combination effects. The failure criteria distinguish between matrix failure, fibre kinking and fibre tensile failure. In-situ strengths are used for matrix failure. Propagation of failure takes into consideration the fracture energy associated with each failure mode and, for matrix failure, the accumulation of cracks in the plies. The model is used to make blind predictions of all test cases from the third World-Wide Failure Exercise.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Analyse contrainte, Stress analysis, Análisis tensión, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Résistance compression, Compressive strength, Resistencia compresión, Résistance traction, Tensile strength, Resistencia tracción, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, Composite laminates, failure criterion, laminate strength, and stress―strain behaviour

This paper represents the authors' contribution to Part B of the second world wide failure exercise, in which the failure predictions and stress―strain curves of 12 test cases are compared with experimental data. The paper briefly reviews the methodology presented in second world wide failure exercise Part A, which includes a semi-analytical stress analysis model and Christensen's failure criteria. A further development in this paper is to introduce a new failure criterion developed also by Christensen and the application of the criterion in conjunction with the stress model. These failure criteria have no adjustable parameters and only depend upon a minimal number of measurable failure properties. Comparisons between the theoretical predictions using different criteria and the experimental results provided by the second World-Wide Failure Exercise organizers are shown in diagrams. It appears that Christensen's failure criteria for anisotropic fiber composite materials predict the failure strength satisfactorily in most of the test cases. Christensen's Polynomial invariants theory compares also well with the experimental results. However, the layup-dependent strength properties required in the criterion are sometimes very difficult to evaluate without performing experimental tests.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Modèle non linéaire, Non linear model, Modelo no lineal, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Renforcement mécanique, Strengthening, Refuerzo mecánico, Résistance compression, Compressive strength, Resistencia compresión, Résistance traction, Tensile strength, Resistencia tracción, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, Rupture pli, Composite laminate, envelope, nonlinear response, progressive ply failure, and triaxial loading

This article represents our contribution to Part B of the 2nd Worldwide Failure Exercise (WWFE-II), where comparisons between epoxy/lamina/laminate response and failure predictions, based on maximum strain failure criterion, and experimental results are made. Correlations between actual test data and our nonlinear stress-strain response and failure envelope predictions under multi-axial loading for 12 different case studies are presented and discussed. Although our approach to modeling composite failure ranked high when applied to biaxial in-plane loading analysis, the theory does not consistently capture the inherent strengthening mechanisms that can be attributed to triaxial loading and hydrostatic pressure. It is expected that the incorporation of a strain-based ply-level failure criterion that introduces some form of strengthening mechanism under a three-dimensional stress state would significantly improve the accuracy of our predictions.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Analyse contrainte, Stress analysis, Análisis tensión, Délaminage, Delamination, Delaminación, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode empilement, Stacking sequence, Modo apilamiento, Mode rupture, Fracture mode, Modo ruptura, Mécanique rupture, Fracture mechanics, Mecánica ruptura, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Matériau fibre multidirectionnelle, Stratifié croisé, Polymer-matrix composites, damage mechanics, matrix cracking, and transverse cracking

This is a contribution to the exercise that aims to benchmark and validate the current continuum damage and fracture mechanics methodologies used for predicting the mechanical behaviour of fibre-reinforced plastic composites under complex loadings. The paper describes an analytical approach to predict the effect of intra- (matrix cracking and splitting) and inter-laminar (delamination) damage on the residual stiffness properties of the laminate, which can be used in the post-initial failure analysis, taking full account of damage mode interaction. The approach is based on a two-dimensional shear lag stress analysis and the equivalent constraint model of the damaged laminate with multiple damaged plies. The application of the approach to predicting degraded stiffness properties of a multidirectional laminate with multilayer intra- and inter-laminar damage is demonstrated for [0/90/0] and [0/908/0] cross-ply laminates made from a specific glass/epoxy system under in-plane uniaxial and biaxial loading damaged by transverse and longitudinal matrix cracks and crack-induced transverse and longitudinal delamination.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Domaines d'application, Application fields, Matière plastique, Plastics, Material plástico, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Assemblage collé, Adhesive joint, Ensambladura pegada, Batterie lithium, Lithium battery, Epoxyde résine, Epoxy resin, Epóxido resina, Etude expérimentale, Experimental study, Estudio experimental, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Moulage sous vide, Vacuum molding, Moldeo en vacío, Plastique alvéolaire, Cellular plastic, Plástico espumoso, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété électrique, Electrical properties, Propiedad eléctrica, Résistance compression, Compressive strength, Resistencia compresión, Résistance flexion, Bending strength, Resistencia flexión, SAN, Stratifié, Laminate, Estratificado, Structure sandwich, Sandwich structure, Estructura sandwich, Carbon, Ragone, battery, epoxy, lithium-ion, pouch-cell, and unmanned

Multifunctional structure-battery composites were developed using fiber reinforced marine composites for structure function and rechargeable lithium-ion cells for energy storage and structure function. Laminate, sandwich, and modular beam configurations were fabricated and tested to determine flexural stiffness and strength, energy storage capacity versus discharge rate, and buoyancy (density). The structure-battery composites exhibited higher flexural stiffness but lower strength than equivalent unifunctional designs, energy storage capacities between 40 and 60 Wh/L, and buoyancies bracketing the unifunctional specimen values. Issues requiring further attention include: improved bending strength, simplified fabrication, reversible attachments for modular components, electrical wiring and connections, and battery management circuitry.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Matériaux composites, Composites, Alignement, Alignment, Alineamiento, Conductivité thermique, Thermal conductivity, Conductividad térmica, Effet température, Temperature effect, Efecto temperatura, Epoxyde résine, Epoxy resin, Epóxido resina, Etude expérimentale, Experimental study, Estudio experimental, Interface solide solide, Solid solid interface, Interfase sólido sólido, Matériau composite, Composite material, Material compuesto, Modélisation, Modeling, Modelización, Morphologie, Morphology, Morfología, Méthode mesure, Measurement method, Método medida, Nanocomposite, Nanocompuesto, Nanotube carbone, Carbon nanotubes, Nanotube multifeuillets, Multiwalled nanotube, Propriété thermique, Thermal properties, Propiedad térmica, Propriété travers court, Through thickness property, Propiedad corta travesía, Recuit, Annealing, Recocido, Alignement nanotubes, Thermal interface materials, multiwalled carbon nanotube epoxy composites, and three omega thermal conductivity measurements

This paper reports development and thermal characterization of tin-capped vertically aligned multiwalled carbon nanotube array composites for thermal energy management in load-bearing structural applications. Three-omega voltage measurements are used to characterize thermal conductivity in the vertically aligned multiwalled carbon nanotube-epoxy composites as well as in its individual constituents, i.e. bulk epon-862 (matrix) and tin thin film in the temperature range 240 K―300 K, and in individual multiwalled carbon nanotubes at room temperature taken from the same vertically aligned multiwalled carbon nanotube batch as the one used to fabricate the carbon nanotube-epoxy composites. A I-D multilayer thermal model that includes effects of thermal interface resistance is developed to interpret the experimental results. The thermal conductivity of the carbon nanotube-epoxy composite is estimated to be ∼5.8 W/m-K and exhibits a slight increase in the temperature range of 240 K to 300 K. The study suggests that morphological structure/quality of the individual multiwalled carbon nanotubes as well as thin tin capping layer are dominating factors that control the overall thermal conductivity of the thermal interface materials. These results are encouraging in light of the fact that thermal conductivity of a vertically aligned multiwalled carbon nanotube array can be increased by an order of magnitude by using a standard high-temperature post-annealing step. In this way, multifunctional (load bearing) thermal interface materials with effective through-thickness thermal conductivities as high as 25 W/m-K can potentially be fabricated.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Constante élasticité, Elastic constant, Constante elasticidad, Délaminage, Delamination, Delaminación, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Modèle non linéaire, Non linear model, Modelo no lineal, Modélisation, Modeling, Modelización, Mécanique rupture, Fracture mechanics, Mecánica ruptura, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Damage, crack density, delamination, strength, and third World-Wide Failure Exercise

This article is the author's contribution to the third World-Wide Failure Exercise which aims at benchmarking current damage models for composites. Reduction of thermo-elastic constants of laminates and their nonlinear behaviour due to intralaminar cracking and nonlinear shear response of the composite are analysed using global―local approach. The macroscopic properties of damaged laminates are expressed in simple forms containing density of intralaminar cracks and their surface displacement features obtained from local solutions. The initiation and evolution of the intralaminar damage is analysed using strength-based approach for laminates with thick layers and fracture mechanics approach for thin layers. Due to a lack of information, certain characteristics, such as statistical failure properties distribution parameters and transition point (thickness) from strength to fracture mechanics applicability, were assumed. All calculations are based on analytical expressions, some of which were developed previously through numerical analysis. The present method was applied to solve 9 out of the 13 test cases of the third World-Wide Failure Exercise and that was sufficient to illustrate the capability of the damage model.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Divers, Miscellaneous, Etude expérimentale, Experimental study, Estudio experimental, Formation motif, Patterning, Formacíon motivo, Interaction solide liquide solide, Solid liquid solid interaction, Interacción sólido líquido sólido, Mode rupture, Fracture mode, Modo ruptura, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété surface, Surface properties, Propiedad superficie, Propriété traction, Tensile property, Propiedad tracción, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Résistance flexion, Bending strength, Resistencia flexión, Silicium, Silicon, Silicio, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Simulation numérique, Numerical simulation, Simulación numérica, Tension superficielle, Surface tension, Tensión superficial, Multifunctional integration, energy harvesting, and surface tension

We report a novel strategy that exploits the unique mechanical characteristics of microscale liquid elements to enable versatile multifunctional integration of brittle components into load-bearing structures. The preliminary feasibility of this integration strategy is demonstrated experimentally using chemically patterned 500 -μm-thick silicon chips to emulate brittle functional components. A systematic study of the mechanical characteristics of microscale liquid bridges, including the force-gap relations under axial loading and the control of rupture distances, is discussed to help guide the systematic design of liquid-based mechanical elements for multifunctional integration.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Charge multiaxiale, Multiaxial load, Carga multiaxial, Critère rupture, Fracture criterion, Criterio ruptura, Délaminage, Delamination, Delaminación, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Micromécanique, Micromechanics, Mode rupture, Fracture mode, Modo ruptura, Modélisation, Modeling, Modelización, Méthode élément fini, Finite element method, Método elemento finito, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété thermomécanique, Thermomechanical properties, Propriedad termomecánica, Propriété traction, Tensile property, Propiedad tracción, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Résistance compression, Compressive strength, Resistencia compresión, Résistance flexion, Bending strength, Resistencia flexión, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, GENOA, WWFE-III, damage, failure criteria, micro crack density, micromechanics, multi-axial, and open hole

As a part of a world-wide study, a commercial code (General Optimization Analyzer), based on multi-scale (micro-macro) progressive failure analysis (PFA), is used to provide theoretical predictions for damage development for a set of challenging 13 test cases proposed in the Third World-Wide Failure Exercise (WWFE-III). Multiple failure criteria were utilized aimed at tackling issues related to a wide range of damage modes, being addressed by the WWFE-III. The critical damage events/indexes predictions tracked translaminar and interlaminar composite failures, namely matrix cracking/crack density, damage initiation/propagation, delamination initiation/growth, and their interaction with fiber failure. The composite laminates analysed were both with and without a central hole and the predictions were made using constituent fiber properties and matrix properties based on materials data or identification from ply stress―strain curve inputs. Loadings included uniaxial tension or compression, biaxial, bending, thermal, and loading―unloading.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Critère rupture, Fracture criterion, Criterio ruptura, Délaminage, Delamination, Delaminación, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Micromécanique, Micromechanics, Modèle 3 dimensions, Three dimensional model, Modelo 3 dimensiones, Modèle mécanique, Mechanical model, Modelo mecánico, Modèle non linéaire, Non linear model, Modelo no lineal, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété rhéologique, Rheological properties, Propiedad reológica, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Résistance compression, Compressive strength, Resistencia compresión, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Viscoélasticité non linéaire, Non linear viscoelasticity, Viscoelasticidad no lineal, Vérification expérimentale, Experimental test, Verificación experimental, Polymer―matrix composites, damage model, failure criterion, and multiscale modelling

This paper presents a comparison between the experimental results provided in the PART B of the second World Wide Failure Exercise and the predictions obtained from a Micromechanical-based hybrid mesoscopic 3D approach described in the PART A of this exercise. This hybrid damage and failure approach is based on physical principles and introduces micromechanical aspects (such as the effect of the local debonding on the non-linear behaviour and on the strengths) at the mesoscopic scale. The behaviour of the UD ply is described by a thermo-viscoelastic model. For the failure phenomena, a distinction is made between different modes of failure: failure in fibre mode, in-plane interfibre mode and through-the-thickness interfibre mode. A fine damage model, that describes the evolution of the crack density and of the associated local delamination, is used to take into account the degradation of the mechanical properties of a failed ply in in-plane interfibre mode until the final failure of the laminate. Finally, the final failure of the specimen is defined as a critical loss of rigidity of the laminate. The predictions are in quite good agreement with the experimental results.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des solides, Solid mechanics, Mécanique des structures et des milieux continus, Structural and continuum mechanics, Mécanique de la rupture (fissure, fatigue, endommagement...), Fracture mechanics (crack, fatigue, damage...), Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Constante élasticité, Elastic constant, Constante elasticidad, Critère rupture, Fracture criterion, Criterio ruptura, Endommagement, Damaging, Deterioración, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode empilement, Stacking sequence, Modo apilamiento, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Elastic properties, Test Cases, WWFE-III, input data, and lamina strengths

This paper gives details of the input data and a full description of a set of 13 test cases provided to the participants of the third world-wide failure exercise for use in their theoretical models. World-wide failure exercise is aimed at benchmarking leading methods, capable of predicting initiation and progression matrix cracking and damage and failure in composites. The originators of leading theories were requested to use the exact input data provided here in their blind predictions of the test cases. The input data include all of the elastic constants, ultimate strains and strengths and the nonlinear stress―strain curves for the unidirectional laminae and their constituents. Various types of laminates, chosen for the analysis, are described together with the lay-up, layer thicknesses, stacking sequences and the loading conditions. Detailed instructions, issued to the contributors, are also presented at the end of this paper.

Materials, Matériaux, Mechanics acoustics, Mécanique et acoustique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Stratifiés, Laminates, Contrainte triaxiale, Triaxial stress, Tensión triaxial, Critère rupture, Fracture criterion, Criterio ruptura, Epoxyde résine, Epoxy resin, Epóxido resina, Etude théorique, Theoretical study, Estudio teórico, Fibre carbone, Carbon fiber, Fibra carbón, Fibre minérale, Mineral fiber, Fibra inorgánica, Fibre verre, Glass fiber, Fibra vidrio, Matériau composite, Composite material, Material compuesto, Matériau fibre unidirectionnelle, Unidirectional fiber material, Material fibra unidireccional, Matériau renforcé fibre, Fiber reinforced material, Material reforzado fibra, Mode empilement, Stacking sequence, Modo apilamiento, Modèle mécanique, Mechanical model, Modelo mecánico, Modélisation, Modeling, Modelización, Pression hydrostatique, Hydrostatic pressure, Presión hidrostática, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Simulation numérique, Numerical simulation, Simulación numérica, Stratifié, Laminate, Estratificado, Vérification expérimentale, Experimental test, Verificación experimental, Stratifié croisé, Stratifié monolithique plan, Criteria, Envelope, Triaxial, WWFE-II, failure, hydrostatic, pressure, and through-thickness

This article draws to a conclusion the results from the co-ordinated study known as the Second World-Wide Failure Exercise (WWFE-II). It contains an objective assessment of the performance of 12 leading failure criteria for predicting the response of fibre-reinforced polymer composites when subjected to 3D states of stress. Twelve challenging test problems (Test Cases) were defined by the organisers of WWFE-II, encompassing a range of materials (polymer, glass/ epoxy, carbon/epoxy), lay-ups (unidirectional, angle ply, cross ply and quasi-isotropic laminates) and various 3D stress states (various triaxial strength envelopes, through-thickness and shear loading, and stress―strain curves). A systematic comparison has then been conducted between 'blind' predictions (i.e. without access to the experimental results beforehand) made for each Test Case by the originators of each theory and previously obtained experimental results for each Test Case. In-depth quantitative and qualitative ranking procedures have been employed to identify the strengths and weaknesses of each theory, and the overall effectiveness of each theory as a potential design tool. The theories are grouped according to their degree of maturity and ability to predict accurately the 3D behaviour of composites. The results from this study provide unique information to the community, the intent being that it will form a guide for the selection of the most appropriate failure theory for use in a given design situation.