D amage initiation and development in textile composites: A - PowerPoint PPT Presentation

D amage initiation and development in textile composites: A gallery Stepan V. LOMOV, Dmitry S. Ivanov, Vitaly KOISSIN, Jan KUSTERMANS, Katleen VALLONS, Jian XU, Ignaas VERPOEST Department MTM, Katholieke Universiteit Leuven, Belgium Valter CARVELLI, Vanni Neri TOMASELLI Politecnico di Milano, Italy Björn VAN DEN BROUCKE EADS Innovation Works, Munich, Germany Volker WITZEL IFB - Institut für Flugzeugbau, Universität Stuttgart, Germany 1 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

A gallery 2 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

C ontents 1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite 3. Non-crimp fabric composite 4. Structurally stitched composite 5. Conclusions 3 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite 3. Non-crimp fabric composite 4. Structurally stitched composite 5. Conclusions 4 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Test method: quasi static tension 500 1.E+10 2D-24 1.E+09 400 1.E+08 1.E+07 stress, MPa 300 1.E+06 AE 1.E+05 200 1.E+04 stress-strain 1.E+03 100 AE events 1.E+02 AE cumulative 0 1.E+01 0 0.5 1 1.5 2 2.5 3 3.5 strain, % � 1 � 2 1.E+04 1.E+09 cumulative AE energy energy 1.E+08 energy of 5.E+03 events 1.E+07 b AE energy 0.E+00 1.E+06 strain, % � 1 Displacement-controlled 0 0.2 0.4 0.6 0.8 1 1.E+05 1.E+08 tension (Instron) � min � 2 1.E+04 AE energy Acoustic emission (Vallen) 1.E+03 5.E+07 1.E+02 Strain-mapping (LIMESS) c 0 0.2 0.4 0.6 0.8 1 0.E+00 strain, % a strain, % 0 0.2 0.4 0.6 0.8 1 5 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Test methods: tension-tension fatigue � max stress � min time Load-controlled (MTS, Schenk) R = 0.1 f = 6…10 Hz 6 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

meso-F E : R oad map Geometric modeller Geometry corrector Meshing Assign material N+2 N+1 N properties Boundary conditions FE solver, postprocessor Homogenisation Damage analysis 7 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

D amage model in F E A Damage initiation: Hoffmann Definition of the damage mode Z 2 2 2 ( ) ( ) ( ) F C C C � � � � � � 1 � T � Z 2 � Z � L 3 � L � T T 2 2 2 C C C C C C L � � � � � � 4 � 5 � 6 � 7 � 8 � 9 � L T Z TZ ZL LT 1 1 1 1 � � � C � � � � � � 1 t c t c t c � � 2 F F F F F F � T T Z Z L L � � � 1 1 1 1 � � � C � � � � � 2 � t c t c t c � 2 F F F F F F � � Z Z L L T T � � 1 1 1 1 � � � C � � � � � � 3 t c t c t c � � 2 F F F F F F � � L L T T Z Z � � 1 1 1 1 1 1 � , , C C C � � � � � � 4 5 6 t c t c t c F F F F F F � L L T T Z Z � 2 2 2 � 1 1 1 � � � � � � C , C , C � � � � � � � � � � 7 8 9 � s � � s � � s � F F F � � TZ � � ZL � � LT � � � 8 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite • Static tension • Finite element analysis 3. Non-crimp fabric composite 4. Structurally stitched composite 5. Conclusions 9 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Woven carbon/epoxy composite 10 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Tension 0.016 0.014 0.012 point #1 local strain 0.01 0.008 0.006 0.004 0.002 0 0 0.005 0.01 0.015 average strain 0.014 0.012 point #5 0.01 local strain 0.008 0.006 0.004 0.002 0 0 0.005 0.01 0.015 average strain eps_X at applied strain 1% 11 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

F E modelling: Material properties and mesh coarse mesh: 5375 elements fine mesh: 26,639 elements 12 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

F E modelling: results experiment fine mesh Experiment FEA, fine rough mesh mesh rough mesh stiffening 400 fine mesh stiffening E, GPa 42.9 � 3.8 43.6 0.08 � 0.03 0.07 stress, MPa � 0.24 � 0.05 0.29 200 � _1, % strain, % 0 0.0 0.5 1.0 eps_T, strain 0.29% 0.29% 0. 52% damaged elements 13 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite 3. Non-crimp fabric composite • Tension • Tension-tension fatigue • Finite element analysis 4. Structurally stitched composite 5. Conclusions 14 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

N on-crimp fabric carbon/epoxy composite loading direction 15 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

N C F , T ension (+45/-45, +45/-45) s Loading in fibre direction Damage initiation at strain 0.3% Saturation of the system of transversal cracks 16 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

N C F , tension-tension fatigue MD BD - CD BD + � 1 � _ult 1000 800 Max stress (MPa) 600 400 Fatigue limit is � 1 Damage initiation stress level in static tests in BD+ HIGHER than Damage initiation stress level in static tests in BD- 200 the damage BD+ BD- initiation threshold 0 1,E+00 1,E+01 1,E+02 1,E+03 1,E+04 1,E+05 1,E+06 1,E+07 1,E+08 Number of cycles to failure 17 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

D amage development in fatigue, load 250 MP a 500,000 1,000,000 5,000,000 18 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

D amage saturation in fatigue Load: 250 MPa (damage initiation level) 19 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

N C F , finite element analysis change of Young module mesh in the plies fibre orientations Puck’s stress intensity factor at near an opening the damage initiation level 20 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite 3. Non-crimp fabric composite 4. Structurally stitched composite • Tension • Tension-tension fatigue 5. Conclusions 21 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

S tructurally stitched N C F carbon/epoxy composite areal density, g/sq. m 0° /90° 556 45° /-45° 540 stitching carbon 1K linear density, tex 67 twist, 1/m 15 plate thickness, mm 3.2 VF, % 63 5 mm 22 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Tension: stitched VS non-stitched Change after stitching AE energy non-stitched stitched 23 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Tension: damage patterns strain map (eps_X) on the surface of strain 0.3% the tufted composite non- stitched structural stitching PES stitching on NCF stitched 24 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

Tension-tension fatigue 500 non-stitched Unstitched 0º Unstitched 90º 400 Stress [ MPa] 300 200 100 � 1 Fatigue limit is HIGHER than 0 1.E+ 00 1.E+ 01 1.E+ 02 1.E+ 03 1.E+ 04 1.E+ 05 1.E+ 06 1.E+ 07 the damage Failure Cycles initiation 500 Stitched 0º Stitched 90º threshold 400 Stress [MPa] 300 200 100 � 1 stitched 0 1.E+ 00 1.E+ 01 1.E+ 02 1.E+ 03 1.E+ 04 1.E+ 05 1.E+ 06 1.E+ 07 Failure Cycles 25 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

1. Introduction: Experimental and modelling methods for studying progressive damage 2. Woven composite 3. Non-crimp fabric composite 4. Structurally stitched composite 5. Conclusions 26 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm

C onclusions 1. The methodology of studying damage processes in textile composites , has been successfully applied to different materials in conjunction with fatigue testing and FE modelling. 2. Clear relation is identified between the damage initiation limit in static tests and fatigue life limit , as well as analogy between the progressive damage patterns for static tests (increasing strain) and fatigue (loading cycles). 3. Meso-FE modelling proved to be able to produce adequate description of damage processes in textile composites. 27 downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm