1,198 research outputs found
Damage characterization during high temperature fatigue of off-axis woven organic matrix composites for aircraft applications
No full textThe present work focuses on damage characterization during high temperature fatigue of 8HS woven [45]6 carbon HTS40 carbon fibre/polyimide matrix composite samples. Fatigue tests are performed under controlled environment (air, 2 bar O2, 2 bar N2) at 250°C by using a specific experimental setup developed at PPRIME Institute; Digital Image Correlation (DIC) and μ-Computed Tomography (μCT) are used for monitoring the evolution of sample behaviour during fatigue. It is shown that these two techniques are effective and complementary for damage assessment under fatigue at high temperature under aggressive environment: a rich characterisation of damage extent and orientation can be provided which allows damage being formalised in a way that can be naturally integrated within the context of damage-dependent behaviour models. The employment of such description allows performing full assessment of the effects of environmental fatigue
Environmental Effects on High Temperature Fatigue of Carbon-Polyimide Textile Composites for Aircraft Applications
No full textEffets de l'Environnement sur la Fatigue en Température de Composites tissés C/Polyimide pour Applications Aéronautiques
No full textEnvironmental Effects on High Temperature Fatigue of Carbon-Polyimide Textile Composites for Aircraft Applications
No full textFatigue Multi-physique de Matériaux Composites à Matrice Organique Stratifiés Croisés [0/90]s pour Applications Aéronautiques / Multiphysical Fatigue of Laminated Cross-ply [0/90]s Organic Matrix Composite Materials for Aircraft Applications
No full textMicro-CT analisys of interlaminar graded interface strength (IGIS) composites based on a thermoplastic matrix
No full textThe hybridization approach in composites is used to improve the impact resistance and the damage tolerance of laminates. It is usually based on the use of two different reinforcing fibres (alternatively stacked, commingled or interpenetrated), one having high stiffness and the other having high toughness. Such approach is effective in improving the low velocity impact resistance of the composites but it poses new issues related to the different specific properties of used fibres (coefficient of thermal expansion, interface compatibility, residual stresses after the laminate production to name a few). A new design has been recently proposed for thermoplastic composites based on the gradation of the interlaminar interface strength (IGIS). The interface strength between fibres and matrix is graded through the thickness by alternating woven fibres with compatibilized or not compatibilized polymeric layers. IGIS laminates involving a commercial grade of polypropylene (PP) as matrix and a woven glass fabric as the reinforcement have been prepared with different interface strength configurations (symmetrically or asymmetrically with respect to the middle plane) by means of the well-known film stacking technique. In this contribution Micro Computerized Axial Tomography (MicroCT) analysis was used to investigate the actual damage mechanisms occurring in IGIS laminates and showed how the graded interface strength is capable of shifting fibre breakage at higher impact energies and allowing elastic recovery in conditions such to significantly damage the fully compatibilized laminate configuration. © 2016, European Conference on Composite Materials, ECCM. All rights reserved
Multi-Physical Fatigue of Laminated and Textile Organic Composite Materials for Aircraft Applications
No full textFatigue Multi-physique de Matériaux Composites à Matrice Organique Stratifiés et Tissés pour Applications Aéronautiques
No full textDamage tolerance of carbon/flax hybrid composites subjected to low velocity impact
No full textHybrid laminates produced using carbon (C) and flax (F) fibre epoxy prepregs were fabricated with two different stacking sequences based on the presence of flax fibre laminates as outer layers and carbon as inner layers (FCF) or vice versa (CFC). Pure flax and pure carbon fibre reinforced laminates were also fabricated as a reference. Experimental tests were performed, which included four-point bending, falling weight impact tests at energies ranging from 5 to 30 J with determination of the barely visible impact damage (BVID) and post-impact flexural tests. As a whole, CFC proved slightly superior to FCF as for flexural performance, although the presence of flax laminates on the outside guaranteed a higher impact damage tolerance, acting as hindrance to crack propagation in the laminate. Specimens impacted at 10 J were also subjected to tensile tests monitored by Digital Image Correlation (DIC) that allowed preliminary identification of peculiar failure modes of the hybrid laminates
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