24.2.1-R8 INFLUENCE OF INACCURACIES IN PERMEABILITY MEASUREMENTS

DC.BERG (CLAUSTHAL UNIVERSITY OF TECHNOLOGY), M.DICKERT, D.MEINERS, G.ZIEGMANN

This work investigates the effects of inaccuracies occuring during permeability measurements and their impact on the measured values. Factors considered are the areal weight of the fabric, the pressure gradient across the preform and the effect of race tracking.

24.2.1-R9 TECHNOLOGICAL APPROACH TO FATIGUE LIFE PREDICTION OF CFRP

J.BRUNBAUER (INSITUTE FOR MATERIALS SCIENCE AND TESTING OF POLYMERS), G.PINTER

Studies on experimental measurement of stiffness properties of unidirectional carbon/epoxy laminates under tension-tension fatigue loads are presented. The results can be used to measure adequate cycle-dependent material properties for implementation in classical laminate theory or software based fatigue life prediction.

24.2.1-R10 AFOSR.2/3

24.2.1-R11 EXPERIMENTAL AND NUMERICAL ANALYSIS OF FIBRE ORIENTATION IN INJECTION MOULDED SHORT GLASS FIBRE REINFORCED POLYAMIDE 6 NOTCHED SPECIMENS

P.CATON-ROSE (UNIVERSITY OF BRADFORD), P.HINE, A.BERNASCONI, E.CONRADO

Autodesk Moldflow Simulation Insights has been used to predict the fibre orientation within notched specimen injection mouldings. Compared to experimentally determined values the Reduced Strain Closure model was shown to most closely represent the fibre orientation within the moulded components

24.2.1-R12 INFLUENCE OF MATRIX RESIN ON TIME-TEMPERATURE DEPENDENT STRENGTH OF UNIDIRECTIONAL CFRP

M.NAKADA (KANAZAWA INSTITUTE OF TECHNOLOGY), S.OHTA, Y.MIYANO, N.SEKINE, T.MATSUMOTO

The time and temperature dependence of static strength in four directions of unidirectional CFRP is discussed based on the time-temperature superposition principle which holds for the viscoelastic behavior of matrix resin.

24.2.1-R13 MODELLING OF MECHANICAL PROPERTIES OF RANDOMLY ORIENTED STRANDS THERMOPLASTIC COMPOSITES

M.SELEZNEVA (MCGILL UNIVERSITY), S.MELDRUM, S.ROY, L.LESSARD, A.YOUSEFPOUR

Strength and modulus of Randomly Oriented Strand (ROS) composites are modelled using a stochastic finite element technique, which employees the concept of random strands generation to model variability. The model shows that failure is matrix-dominated and follows the “weakest-link” principle.

24.2.1-R14 NUMERICAL INVESTIGATION OF DELAMINATION IN L-SHAPED CROSS-PLY COMPOSITE BRACKET

M.GUMUS (MIDDLE EAST TECHNICAL UNIVERSITY (METU)), B.GÖZLÜKLÜ, D.ÇÖKER

Interlaminar normal stresses are induced with interlaminar shear stresses leading to mixed-mode delamination (MMD) in curved cross-ply composite laminates. Delamination is studied using explicit FEM and Cohesive Zone Modelling. Load-displacement curves and response of the specimen are compared with experiments.

24.2.2-R8 STUDY OF THE RESIDUAL STRAINS DEVELOPED DURING PROCESS OF EPOXY AND POLYURETHANE MATRIX COMPOSITES

V.MICHAUD, M.BENAVENTE, L.CANAL (EPFL), JA.MÅNSON

Fiber Bragg grating sensors is an adequate technique to determine the strains build-up during processing of thermoset matrix composite laminates. This technique is applied to study the behavior of polyurethane-matrix composites for high volume applications.

24.2.2-R9 CHARACTERISATION OF FATIGUE MICROMECHANISMS IN TOUGHENED CARBON FIBER-POLYMER COMPOSITES USING SYNCHROTRON RADIATION COMPUTED TOMOGRAPHY

SC.GARCEA (UNIVERSITY OF SOUTHAMPTON), I.SINCLAIR, SM.SPEARING

Toughening micromechanisms in double notch carbon/epoxy coupons subjected to fatigue loading have been investigated using synchrotron radiation computed tomography, and the behaviour compared with the untoughened system.

24.2.2-R11 INFLUENCE OF NOTCHES ON THE FATIGUE BEHAVIOUR OF SHORT FIBRE REINFORCED POLYAMIDE CONSIDERING ENVIRONMENTAL TEMPERATURE

N.NIENHAUS (SCHAEFFLER TECHNOLOGIES GMBH & CO. KG), S.KURZBECK

In this work the combined effect of notches and temperatures on the fatigue behaviour of short glass fibre reinforced polyamide 66 (PA66-GF25) was investigated and characterized. The results show a significant influence of temperature on the supporting effect.

24.2.2-R12 EXPERIMENTAL STUDY OF THE PROPAGATION OF DELAMINATION UNDER OXIDIZING ENVIRONMENT AND MECHANICAL LOADING

F.DAGHIA (ENS CACHAN), C.CLUZEL

Polymer matrix composites under high temperatures suffer from oxidation of the polymer, which is strongly coupled with cracking. A new experimental method, which allows oxidation-driven crack propagation under different external mechanical loads, is developed to investigate this chemo-mechanical coupling.

24.2.2-R13 DYNAMIC CRACK ANALYSIS IN ANISOTROPIC FUNCTIONALLY GRADED MATERIALS BY A TIME-DOMAIN BEM

M.WUENSCHE (UNIVERSITY OF SEVILLE), A.SAEZ, F.GARCIA-SANCHEZ

A time-domain BEM for dynamic crack analysis in 2D, anisotropic and functionally graded composites is presented. First numerical examples show the influence of the material gradation on the dynamic SIFs and indicate the suitability of the BEM for such materials.

24.2.2-R14 AN INNOVATIVE USE OF X-RAY COMPUTED TOMOGRAPHY IN COMPOSITE IMPACT DAMAGE CHARACTERISATION

F.LEONARD (THE UNIVERSITY OF MANCHESTER), J.STEIN, P.WITHERS, A.WILKINSON

This study presents how X-ray computed tomography (CT) can be employed to obtain a more complete 3-dimensional description of impact damage in carbon fibre reinforced polymer (CFRP) composites.

24.2.3-R8 MATERIAL OPTIMISATION FOR RTM FABRICATION OF GFRP FLANGES SPECIFICALLY IN TERMS OF THE CREEP COMPLIANCE

A.EGGERS (TECHNICAL UNIVERSITY OF CLAUSTHAL), D.MEINERS, G.ZIEGMANN, S.MORITZ, K.MAILE

The creep compliance of GFRP flanges can be reduced by using the RTM-technique. For RTM-technique a material optimisation of the used textile regarding flexural properties, creep behaviour and easy handling was made. TTS-method for testing the creep behaviour was used.

24.2.3-R9 LATE-STAGE FATIGUE DAMAGE IN A GLASS/EPOXY NON-CRIMP 3D ORTHOGONAL WOVEN FABRIC COMPOSITE

L.BAIOCCHI, T.CAPELL, S.MCDONALD, S.OGIN (UNIVERSITY OF SURREY), P.POTLURI et al.

Extensive fibre fractures within sections of warp tows closest to z-crowns in a fatigue-cycled glass/epoxy 3D orthogonal woven fabric composite is suggested to be a consequence of stress concentrations due to matrix cracks in two orthogonal planes.

24.2.3-R11 FATIGUE DAMAGE INVESTIGATION OF PA66/GF30 BY X-RAY MICROTOMOGRAPHY

F.ARIF, F.MERAGHNI (ENSAM/ARTS - METZ), N.SAINTIER, Y.CHEMISKY, J.FITOUSSI et al.

Damage behavior of dry as molded short glass fiber reinforced polyamide-66 (PA66/GF30) under fatigue loading has been investigated by X-ray micro-computed tomography. Based on µCT images, fiber/matrix interface debonding is considered as the main fatigue damage mechanism.

24.2.3-R12 METHODOLOGY TO CHARACTERIZE THE INFLUENCE OF THERMAL AGEING ON STRENGTH PROPERTIES OF EPOXY COMPOSITE MATRICES

Y.PANNIER (PPRIME INSTITUTE), C.GUIGON, E.GAUTHIER, MC.LAFARIE-FRENOT

To evaluate the influence of thermal ageing oxidation on epoxy resin mechanical properties, ultramicroindentation tests and four points bending tests are conducted. They reveal a local increase of elastic properties and a ductile to brittle failure transition.

24.2.3-R13 A COUPLED THERMO-ELECTRO-MECHANICAL MODEL FOR FRACTURE IN SOLAR CELLS

M.PAGGI (IMT INSTITUTE FOR ADVANCED STUDIES LUCCA), I.BERARDONE, M.CORRADO

Micro-cracks and grain boundaries in solar cells are impacting on the electric power-loss of photovoltaic modules, a complex laminate structure. In this contribution, a one-dimensional model for simulating the electric current distribution in solar cells with cracks is proposed.

24.2.3-R14 STRAIN RATE EFFECTS ON THE MECHANICAL BEHAVIOR OF CARBON-THERMOPLASTIC MATRIX WOVEN COMPOSITES

JC.WALRICK (ESTACA – CAMPUS OUEST, RUE GEORGES CHARPAK, BP 76121, 53061 LAVAL CEDEX 9), M.BOCQUET, J.FITOUSSI

The proposed contribution concerns the application of an optimized approach dedicated to the experimental characterization of the overall dynamic mechanical behavior of a Twill woven carbon-polyamide laminate. The methodology aims to report the strain rate effect on the material response.

24.2.4-R8 A QUANTITATIVE EVALUATION OF THE UNCERTAINTY OF PERMEABILITY MEASUREMENTS IN CONSTANT THICKNESS FIBRE REINFORCEMENTS (RTM)

M.BODAGHI (UNIVERSITY OF PORTO), P.GONÇALVES, N.CORREIA

This study presents an evaluation of the uncertainties produced by measuring instruments and equipment in permeability determination for LCM. Preliminary results reveal that both pressure and porosity parameters have significant influence on permeability measurements.

24.2.4-R9 RAPID DETERMINATION OF THE FATIGUE PROPERTIES OF CARBON FIBER EPOXY MATRIX COMPOSITE LAMINATES BY SELF-HEATING TESTS

L.GORNET (ECOLE CENTRALE DE NANTES), O.WESTPHAL, P.ROZYCKI, L.STAINIER, G.KEMLIN

Self-heating measurements under cyclic loading allow fast estimation of fatigue properties of composites. Fatigue tests are conducted to obtain high-cycle fatigue (S-N) curves. The fatigue limits of the different composite lay-ups tested were successfully compared with self-heating test method results.

24.2.4-R11 METHODOLOGY TO SIMULATE AND VALIDATE THE FAILURE BEHAVIOR OF SHORT FIBER REINFORCED POLYMER COMPONENTS USING THE FIRST PSEUDO GRAIN FAILURE MODEL

M.REITER (JOHANNES KEPLER UNIVERSITY LINZ), M.JERABEK, Z.MAJOR

A methodology to simulate SFRP components using a coupled mean field homogenization and FE simulation approach is presented and validated. For the material model calibration, special injection molded specimens with nominal fiber orientations of 0°, 45° and 90° were produced.

24.2.4-R12 ON THE EFFECT OF THERMAL AGEING IN CFRP MECHANICAL PROPERTIES

S.GONZÁLEZ (CENTER FOR ADVANCED AEROSPACE TECHNOLOGIES - CATEC), J.DOMÍNGUEZ, F.LASAGNI

In this work, thermal cycles have been performed in aeronautic composite materials using non-reactive and oxidative atmospheres. Mechanical properties (fatigue/static) are analysed and related to composite degradation. Effect of thermal cycling in mechanically loaded CFRP structural part was also investigated.

24.2.4-R13 MODELLING MIXED-MODE TRANSLAMINAR FRACTURE

M.LAFFAN (IMPERIAL COLLEGE LONDON), ST.PINHO, P.ROBINSON

This work concerns development of a damage model that captures the delamination failure exhibited by notched laminates under mixed-mode in-plane loading. The model can represent delamination without ply-by-ply modelling or cohesive elements and will be validated against experimental results.

24.2.4-R14 INVESTIGATION OF IMPACT DAMAGE OF TAPERED COMPOSITE LAMINATES

H.ABDULHAMID (SOGETI HIGH TECH AND ICA), C.BOUVET, L.MICHEL, J.ABOISSIERE, C.MINOT

This work deals with numerical simulation of impact damage of tapered composite laminates. The model reproduces three types of damage: matrix cracking, delamination and fibre rupture. Good agreement with experiment is obtained in terms of force-displacement curve and delamination shape.