23.2.1-R8 INTEGRAL OR DIFFERENTIAL DESIGN FOR A COST EFFECTIVE COMPOSITE AUTOMOTIVE BODY STRUCTURE

P.MÅRTENSSON (KTH, ROYAL INSTITUTE OF TECHNOLOGY/VOLVOCARS), D.ZENKERT, M.ÅKERMO

Part cost must be improved in order to make carbon fibre composites useful for the automotive industry. This paper presents an investigation of how complexity and size of a structure affect the manufacturing design choice between integral and differential design.

23.2.1-R9 INFLUENCE OF IMPACT DAMAGE ON THE FATIGUE BEHAVIOUR OF COMPOSITES

N.KOSMANN (HAMBURG UNIVERSITY OF TECHNOLOGY), H.SCHMUTZLER, K.SCHULTE, B.FIEDLER

Defects in composite structures, such as impact damages have a major influence on the fatigue behaviour.Based on the conducted experiments the influence of impact damages on fatigue life of glass fibre based NCF composites was characterised.

23.2.1-R10 COMPARISON OF COHESIVE ZONE MODELS USED TO PREDICT DELAMINATION INITIATED FROM FREE-EDGES : VALIDATION AGAINST EXPERIMENTAL RESULTS

A.UGUEN (ENSTA BRETAGNE), L.ZUBILLAGA, A.TURON, N.CARRERE

The objective of this paper is to predict the free-edge delamination of composite materials. For this purpose a comparison between different cohesive zone models is presented as well as the different parameters which influence the damage law.

23.2.1-R11 INFLUENCE OF TOOL GEOMETRY IN DRILLING OF CFRP

J.DIAZ, N.FEITO (UNIVERSIDAD CARLOS III DE MADRID), A.DIAZ, JL.CANTERO, J.LÓPEZ-PUENTE et al.

A study about drilling woven CFRPs materials has been developed. Three different point angles and different cutting parameters were tested with two levels of wear. Feed forces and delamination were analyzed. Also a numerical model for both geometries is validated.

23.2.1-R12 AN APPROXIMATE ANALYTIC SOLUTION FOR THE STRESSES AND DISPLACEMENTS OF THIN-WALLED ORTHOTROPIC BEAMS SUBJECTED TO BENDING

F.VLAK (UNIVERSITY OF SPLIT, FESB), R.PAVAZZA, M.VUKASOVIC

An approximate solution for the stresses and displacements according to the theory of bending with influence of shear is given. The solutions are given in the analytic form. The unidirectional orthotropic beams with double symmetrical cross-section are considered.

23.2.1-R13 MESH-OBJECTIVE MULTI-SCALE FINITE ELEMENT ANALYSIS OF UNIDIRECTIONAL FIBROUS MATERIALS USING ENERGY BASED FAILURE MECHANISM

P.MEYER (AEROSPACE ENGINEERING), AM.WAAS

A integrated finite element multi-scale method (IFEM) has been developed. Damage of macroscopic models is predicted by integrating failure of fibrous materials on the micro-scale level, e.g. Fiber, Matrix, based on the crack-band methodology.

23.2.1-R14 THE INFLUENCE OF PRE-STRESS AND CURVATURE ON IMPACT RESPONSE OF CURVED COMPOSITE LAMINATES

G.MINAK (UNIVERSITY OF BOLOGNA), T.BRUGO, A.ZUCCHELLI

In this paper the effect of pre-stress on impact response of curved laminates is considered. Results show that pre-stress decreases damaged area caused by impact. This phenomenon is different with what observed in plate laminates and is useful for designers.

23.2.2-R8 MANUFACTURING COST COMPARISON OF RTM, HP-RTM AND CRTM FOR AN AUTOMOTIVE ROOF

M.BASKARAN, I.ORTIZ DE MENDIBIL, M.SARRIONANDIA, J.AURREKOETXEA (MONDRAGON UNIBERTSITATEA), J.ACOSTA et al.

The manufacturing cost of conventional RTM, HP-RTM and CRTM have been analyzed for an automotive roof case. Results from process simulation have been used to define the cycle time, equipment specifications and layout of each technology.

23.2.2-R9 STATIC AND FATIGUE PERFORMANCE OF THICK LAMINATES - TEST DESIGN AND EXPERIMENTAL COMPRESSION RESULTS

F.LAHUERTA (KNOWLEDGE CENTRE WMC. KLUISGAT 5, 1771 MV WIERINGERWERF, THE NETHERLANDS), T.WESTPHAL, R.NIJSSEN, F.VAN DER MEER, B.SLUYS

The aim of this work is to study the thickness effect in static and fatigue tests of GFRP UD coupons. Thickness scaled compression coupons has been designed. Static and fatigue tests are reported for 4, 10, 20 mm thick coupons.

23.2.2-R10 MODELLING SOFT BODY IMPACT OF THROUGH-THICKNESS REINFORCED COMPOSITES

G.MOHAMED (UNIVERSITY OF BRISTOL), G.KALWAK, SR.HALLETT, M.JEVONS

This paper presents a numerical study to predict the effectiveness of z-pins in controlling delamination in composite beams subject to high-velocity soft body impact. Improvements in delamination threshold velocity, relative to unpinned specimens, is presented and discussed.

23.2.2-R11 EXPERIMENTAL STUDY OF THE AXIAL CUTTING FORCES IN THE DRY DRILLING OF CFRP

A.PORTAL (AIRBUS MILITARY), SR.FERNANDEZ, P.MAYUET, P.ARROYO, J.SALGUERO et al.

This paper reports on the results of a study on the axial cutting forces in the dry drilling of CFRP and its evolution with the main drilling parameters. First empirical model have been also proposed.

23.2.2-R12 ANALYTICAL AND NUMERICAL MODELS FOR PREDICTING UNFOLDING FAILURE IN COMPOSITE BEAMS

E.GRACIANI (UNIVERSIDAD DE SEVILLA), A.BLÁZQUEZ, J.CAÑAS, F.PARÍS

Stresses responsible for unfolding failure in a composite T joint are evaluated analytically using a curved beam model. Results are compared with those obtained with a plane finite element model.

23.2.2-R13 INSTABILITY ANALYSIS OF THE FIBRE-MATRIX DEBOND ONSET AND GROWTH UNDER TRANSVERSE TENSION

L.TAVARA (UNIVERSIDAD DE SEVILLA), V.MANTIČ, E.GRACIANI

A careful numerical analysis using the Linear Elastic-Brittle Interface Model predicts a sudden and large breakage of the fibre-matrix interface under displacement control at the outer matrix-cell-boundary; while a stable debond growth occurs under crack opening control.

23.2.2-R14 IMPACT VALIDATION AND SIMULATION OF COMPOSITE AEROFOIL STRUCTURES

C.DERDAS, M.JEVONS (ROLLS-ROYCE PLC)

This paper presents the impact simulation results and validation of a composite aerofoil structure against crushing and soft body impact threats at a modelling scale appropriate for full component analysis using continuum damage mechanics and cohesive zone modelling.

23.2.3-R8 TESTING OF THE STRENGTH OF AN ALTERNATIVE MANUFACTURING METHOD FOR BOLTED JOINTS USED IN A GFRP-ROTOR OF AN AXIAL-FLUX ELEKTRIC MOTOR FOR SERIAL PRODUCTION IN AUTOMOTIVE

M.BUECKER (INSTITUTE FOR COMPOSITE MATERIALS), M.MAGIN

The strength of two different manufacturing types of threads in two types of thick-walled GFRP laminates is tested. The strength of the molded-in thread of a cross-ply laminate at pull-out is lower but a higher strength in bearing test.

23.2.3-R9 FATIGUE DELAMINATION GROWTH ONSET OF TWO WOVEN LAMINATES

M.OLAVE (IK4-IKERLAN), I.VARA

Mode I fatigue delamination growth onset of two woven laminates is evaluated for different nesting/shifting values. Static fracture toughness tests showed differences between the materials analysed. In contrast, this work shows a similar behaviour for normalized fatigue onset values.

23.2.3-R10 DELAMINATION RESISTANCE OF THROUGH THICKNESS REINFORCED COMPOSITES

M.YASAEE (UNIVERSITY OF BRISTOL), G.MOHAMED, G.ALLEGRI, SR.HALLETT

The delamination resistance of arrays of Z-Pins are measured in mode I, mode II and mixed mode I/II loading scenarios with a method proposed to measure the apparent toughness of these TTR pins at pre-determined delamination lengths.

23.2.3-R11 ENSURING DRILL QUALITY IN COMPOSITE MATERIALS USING ACOUSTIC EMISSION

M.EATON (CARDIFF UNIVERSITY), M.PEARSON, C.BYRNE, P.PRICKETT, R.PULLIN et al.

The drilling of carbon fibre material was monitored using acoustic emission. Drill bit condition and tool wear were identified using AE signal RMS and contiuous wavestream data were used to indicate induced damage resulting in reduced hole quality.

23.2.3-R12 ANALYTIC EVALUATION OF RADIAL STRESSES IN UNFOLDING FAILURE OF COMPOSITE MATERIALS. COMPARISON WITH NUMERICAL SOLUTIONS

JM.GONZÁLEZ CANTERO (UNIVERSITY OF SEVILLE), E.GRACIANI, A.BLÁZQUEZ, F.PARÍS

Typical analysis of composite laminates do not consider interlaminar stresses, being considered as negligible. A novel calculation method for evaluating stresses in composite curved beams is introduced in this paper and compared with numerical results to show its accuracy.

23.2.3-R13 DETERMINATION OF INPUT PARAMETERS FOR A MIX-MODE COHESIVE ZONE FORMULATION IN A NOVEL METAL-CFRP-JOINING INTERFACE

J.KRONSTEINER (LKR LEICHTMETALLKOMPETENZZENTRUM RANSHOFEN GMBH, AUSTRIAN INSTIUTE OF TECHNOLOGY,), S.UCSNIK, S.STELZER

This paper presents a methodology for an automated determination of input parameters by reverse engineering. With the help of Design of Experiments (DOE) and optimization algorithms, the parameters are investigated by comparison of results from experiments and from numerical simulations.

23.2.3-R14 DYNAMIC MECHANICAL PROPERTIES OF CARBON NANOTUBE-PEEK NANOCOMPOSITES

D.KAKA (UNIVERSITY OF SHEFFIELD), J.RONGONG, A.HODZIC, C.LORD

This research investigates the influence of adding carbon nanotubes on the dynamic mechanical properties of PEEK. Particularly, the effects on stiffness and damping of the nanocomposite material over range of temperatures and loading conditions are considered both experimentally and numerically.

23.2.4-R9 TENSILE FATIGUE BEHAVIOR OF STITCHED CARBON/EPOXY COMPOSITES

A.YUDHANTO (TOKYO METROPOLITAN UNIVERSITY), S.MOROOKA, N.WATANABE, Y.IWAHORI, H.HOSHI

23.2.4-R10 MODEL FOR DELAMINATION PROPAGATION IN MULTILAYERED MATERIALS AT 0º/θº INTERFACES: A COMPARISON BETWEEN EXPERIMENTAL AND FINITE ELEMENTS STRAIN ENERGY RELEASE RATES

JF.CARON (UR-NAVIER), LERPINIERE, A.DIAZ DIAZ, K.SAB

Multilayered delaminated plates are analyzed here using an 2D plate model. Alternative to the existing three-dimensional finite element methods (3D-FEM), the proposed model, named LS1, is a layerwise stress model proving significantly less computationally expensive while accurate and efficient.

23.2.4-R12 ARCHITECTURE AND MATERIALS SELECTION IN MULTI-MATERIALS DESIGN

P.BARACCHINI (BORDEAUX UNIVERSITY), C.GUILLEBAUD, FX.KROMM, A.CATAPANO, M.MONTEMURRO et al.

We present a new strategy for the design of architectured materials based on the simultaneous selction of the architecture and components of the multi-material. Moreover, a genetic algorithm is used to perform the solution search for our problem.

23.2.4-R13 A FULLY COUPLED MULTISCALE SHELL FORMULATION FOR THE MODELLING OF FIBRE REINFORCED LAMINATES

J.FRÄMBY, J.BROUZOULIS, M.FAGERSTRÖM, R.LARSSON (CHALMERS UNIVERSITY OF TECHNOLOGY)

We discuss a fully coupled multiscale method based on computational homogenisation for simulating fibre reinforced laminates. We focus on the accuracy in the through-thickness direction and the benefits thereof in predicting onset of matrix and/or delamination cracks.

23.2.4-R14 THE EFFECT OF MULTIPLE LOW-VELOCITY IMPACT ON FIBRE METAL LAMINATES

P.JAKUBCZAK (LUBLIN UNIVERSITY OF TECHNOLOGY), J.BIENIAŚ, B.SUROWSKA

Due to excellent properties, FMLs have been applied in primary structures of several aircrafts. The goal was to carry out the analysis of impact resistance for FML and investigation of influence of multiple impact on their failure and impact resistance.