Calcul des propriétés élastiques des tissus utilisés dans les matériaux composites

Abstract

Les renforts textiles s'imposent dès qu'il faut réaliser des structures massives ou complexes en matériaux composites, comme certains raccords et jonctions de tubes, des panneaux d'habitation légère, des carters de protection de têtes de puits en fond de mer, etc.Cet article expose les caractéristiques générales d'un renfort textile, puis différentes approches micromécaniques analytiques représentant les tissus à tissage bidimensionnel sont présentées. En partant du plus simple et en allant vers le plus complexe, ces modèles sont l'analogie à un stratifié [0°/90°], la mosaïque en série et en parallèle, les ondulations 1D et les ondulations 2D série-parallèle et parallèle-série. Toutes ces approches sont fondées sur la théorie mécanique des stratifiés.En analysant les résultats d'applications numériques de ces modèles et les résultats expérimentaux, on constate que les modèles des ondulations en 2D procurent les meilleures valeurs estimées des modules élastiques. Les autres modèles n'indiquent que des ordres de grandeurs. COMPUTATION OF ELASTIC PROPERTIES OF FABRICS USED IN COMPOSITE MATERIALSWoven fabric reinforcements are irreplaceable from the moment that heavy or complex composite structures should be manufactured, such as some pipe connections or flanges, light panels for housing, subsea well head protection panels, etc.In this paper overall characteristics of woven fabrics are described, followed by the review of different micromechanical analytical approaches. Starting with the simplest and continueing with the more complex, these models are: the analogy with a [0°/90°] laminate, the series and parallel mosaic models, the 1D fiber undulation model, and the 2D series-parallel and parallel-series fiber undulation models. All these approaches are based on the classical laminated plate theory.Analyzing the results of numerical applications of the models and experimental results, one can notice that both 2D fiber undulation models give the best estimated values for elastic moduli. The other provide a rough estimate of moduli only. Se presentan en este artículo las características generales de un refuerzo textil, así como diversos enfoques micromecánicos analí-ticos que representan los tejidos de tejido bidimensional. Partiendo del más sencillo y llegando al más complejo, estos modelos corresponden a la analogía de un estratificado [0°/90°], el mosaico en serie y en paralelo, las ondulaciones 1D y las ondulaciones 2D serie-paralelo y paralelo-serie. Todos estos enfoques se fundan en la teoría mecánica de los estratificados. CÁLCULO DE LAS PROPIEDADES ELÁSTICAS DE LOS TEJIDOS UTILIZADOS EN LOS MATERIALES COMPUESTOSAl analizar los resultados de aplicaciones digitales de estos modelos y los resultados experimentales, se puede comprobar que los modelos de las ondulaciones en 2D procuran los mejores valores evaluados de los módulos elásticos. Los demás modelos única-mente indican las magnitudes.

Flexural behaviour modelling of carbon/epoxy laminates using the puck-EWM approach

“…In the first step, we model our fabric prepreg ‘carbon/epoxy’ by analogy with a [0°/90°] laminate [27]. The predicted results, using numerical modelling are shown in Tables 4 and 5 and have been compared with the experimental tests.…”

Nonlinear modeling of the failure of a graphite epoxy under a three-point bending test

“…In a second step, we model our fabric prepreg “carbon/epoxy” by analogy with a [0°/90°] laminate 22 (Figure 27). The obtained results are listed in Tables 8 to 12.…”

“…In the case of the fabric, we notice that the criterion overestimates the final failure compared to the experimental results, with an error margin of 35%. This large dispersion can be explained by the approximations imposed by the analogical method, which neglects the effect of interactions between warp and weft fibers 22 (Figure 28).…”

Thermal Ageing of a Hybrid Composite Rod for Next Generation Overhead Power Lines

“…It consists of an aluminum conductor supported by a hybrid composite core made of epoxy matrix reinforced with both unidirectional carbon and glass fibers ( Figure 1). Carbon fibers have been selected for this application because of the very low value of their thermal expansion coefficient in the longitudinal direction [1], thus allowing to design lines with a sag almost independent of temperature variations. However, carbon fibers have been replaced by glass fibers within the composite shell to avoid the galvanic corrosion of the surrounding aluminum conductor [2].…”