Development of a Novel Compact Tension Specimen for Fibre Hybrid Composites

Transcription

1 Development of a Novel Compact Tension Specimen for Fibre Hybrid Composites Tomas Katafiasz: 3 rd Year PhD Candidate 6 th April 2017, CompTest2017, KU Leuven L. Iannucci, E. Greenhalgh 1

2 Industrial Partners

3 Compact Tension Specimen

4 Compact Tension Specimen

5 Compact Tension Specimen

6 Compact Tension Specimen

7 Motivation Fibre Hybrid Composites - Composite - Monolithic metallic BMW 7 Series Courtesy of BMW Ltd. And Hexcel Ltd.

8 Motivation Fibre Hybrid Composites - Fibre hybrid composites: - Cost saving - Localised property enhancement - Smooth surface finish - Pseudo-ductility - Drapeability BMW 7 Series Courtesy of BMW Ltd. And Hexcel Ltd.

9 Issues with translaminar testing Fibre Hybrid Composites - But, issues with compressive properties due to: - Fibre crimp in woven laminae - Fibre waviness in non-crimp fabrics (as discussed in the previous presentation) BMW 7 Series Courtesy of BMW Ltd. And Hexcel Ltd.

10 Fibre hybrid composite - resin film infusion (MTM57 epoxy) INTERLAYER HYBRID 16 plies T700 Carbon Spread Tow (woven) 12 plies S2-Glass Bi-Axial Non-Crimp Fabric 0/90 Carbon 0/90 Glass Resin 0/90 Carbon 0/90 Glass 0/90 Carbon x4 Resin 0/90 Glass 0/90 Carbon Hybrid fibre volume fractions: 35% Carbon, 65% Glass

11 Thermogravimetric Analysis (TGA) W T W gf+cf W gf

12 T700 carbon spread tow / S2-glass NCF / MTM57 epoxy glass carbon glass carbon glass carbon glass carbon glass

13 Compact Tension Specimen

14 Compact Tension Specimen

15 Compact Tension Specimen

16 Compact Tension Specimen

17 ASTM E Compact Tension Specimen

18 Premature Failure in Compact Tension Specimens FM1: Fibre fracture due to longitudinal compressive stress N. Blanco, D. Trias, S.T. Pinho, P. Robinson, Intralaminar fracture toughness characterisation of woven composite laminates. Part I: Design and analysis of a Compact Tension (CT) specimen, Eng. Fract. Mech. 131 (2012)

19 Curved Compact Tension Specimen

20 Curved Compact Tension Specimen

21 Premature Failure in Compact Tension Specimens FM6: Buckling due to high compressive stresses at the right edge N. Blanco, D. Trias, S.T. Pinho, P. Robinson, Intralaminar fracture toughness characterisation of woven composite laminates. Part I: Design and analysis of a Compact Tension (CT) specimen, Eng. Fract. Mech. 131 (2012)

22 Premature Failure in Compact Tension Specimens Gigliotti L, Pinho ST. Translaminar fracture toughness of NCF composites with multiaxial blankets. Mater Des. Elsevier Ltd; 2016;94: A. Ortega, P. Maimí, E. V. González, L. Ripoll, Compact tension specimen for orthotropic materials, Compos. Part A Appl. Sci. Manuf. 63 (2014) X. Li, S.R. Hallett, M.R. Wisnom, N. Zobeiry, R. Vaziri, A. Poursartip, Experimental study of damage propagation in Over-height Compact Tension tests, Compos. Part A Appl. Sci. Manuf. 40 (2009) A. Arteiro, G. Catalanotti, J. Xavier, P.P. Camanho, Large damage capability of noncrimp fabric thin-ply laminates, Compos. Part A Appl. Sci. Manuf. 63 (2014)

23 Notched Curved Compact Tension NCCT (exploded view)

24 Notched Curved Compact Tension NCCT

25 NCCT FE Development Normal modes (buckling) Linear static (maximum strain)

26 NCCT Manufacturing Fibre Hybrid

27 NCCT Manufacturing S2-Glass

28 NCCT Test Set-up LED Lighting Optical strain camera

29 NCCT Optical Data Capture Interlayer Fibre Hybrid 0mm 4mm 9.5mm 15mm

30 NCCT Optical Data Capture S2-Glass (backlit)

31 Data Analysis Area Method critical energy release rate G IC (J/m 2 ) of the material, where E = total energy used to propagate crack (J),a = crack length (m), t = specimen thickness (m)

32 Data Analysis Modified Compliance Calibration Method critical energy release rate G IC (J/m 2 ) of the material, where P c = load at crack length a (N), t = specimen thickness (m), dc/da = function of compliance curve (1/N) Compliance curve captured from FE models

33 NCCT Critical Strain Energy Release Rate: S2-Glass R-Curve

34 Virtual Crack Closure Technique Validation: S2-Glass

35 NCCT Critical Strain Energy Release Rate: R-Curve (area method)

36 NCCT Validation - Impact Modelling Test Rig BSi, BS ISO 18352:2009 Carbon-fibre reinforced plastics - Determination of compression-after-impact properties at a specified impact-energy level, (2009).

37 Drop Tower Impact Set-Up Impact panel Video capture High speed camera Lighting Mirror

38 NCCT Validation - Impact Modelling: Energy based failure Energy based failure VUMAT (user defined material) using Abaqus 6.14 Explicit: L. Iannucci, M.L. Willows, An energy based damage mechanics approach to modelling impact onto woven composite materials-part I: Numerical models, Compos. Part A Appl. Sci. Manuf. 37 (2006) Interlayer hybrid: T700 Carbon Spread Tow woven S2-Glass Non-Crimp Fabric Standardised tests to capture material properties of carbon and glass separately (with glass strain rate effects) New NCCT specimen data to provide translaminar fracture toughness Including cohesive elements to capture delamination Double Cantilever Beam (interlaminar Mode I) 4-Point End Notched Flexure (interlaminar Mode II)

39 NCCT Validation - Impact Modelling PRELIMINARY PRELIMINARY

40 NCCT Validation - Impact Modelling Quarter model about planes of symmetry

41 NCCT Validation - Impact Modelling Quarter model about planes of symmetry

42 NCCT Validation - Impact Modelling Quarter model about planes of symmetry Representative fixed (encastre) rig at edges

43 NCCT Validation - Impact Modelling Quarter model about planes of symmetry Representative fixed (encastre) rig at edges Mesh sensitivity study Initial velocity of tup set equal to experiment

44 NCCT Validation - Impact Modelling Tup: solid elements Rig: solid elements Layup: [C/G/C/G/C/G/C] 4 C: Carbon G: Glass Continuum shell elements Cohesive elements: (capturing delamination) [C/G/C/G/C/G/C] [C/G/C/G/C/G/C] [C/G/C/G/C/G/C] [C/G/C/G/C/G/C]

45 70J Impact Event of Fibre Hybrid Load vs Time

46 70J Impact Event of Fibre Hybrid Load vs Time

47 70J Impact Event of Fibre Hybrid Load vs Time

48 70J Impact Event of Fibre Hybrid Load vs Time

49 FE Impact Damage Correlation - Ultrasonic C-Scans Impact Energy: 70J 2 1

50 FE Impact Damage Correlation - Ultrasonic C-Scans Impact Energy: 70J Fibre fracture in direction 1 2 1

51 FE Impact Damage Correlation - Ultrasonic C-Scans Impact Energy: 70J Fibre fracture in direction 2 2 1

52 Conclusions Translaminar properties of fibre hybrid composites can now be characterised without the need for anti-buckling devices or FE based compliance Fibre hybrid composites can be modelled using energy based failure theories using the NCCT specimen

53 Conclusions Translaminar properties of fibre hybrid composites can now be characterised without the need for anti-buckling devices or FE based compliance Fibre hybrid composites can be modelled using energy based failure theories using the NCCT specimen

54 Conclusions Translaminar properties of fibre hybrid composites can now be characterised without the need for anti-buckling devices or FE based compliance Fibre hybrid composites can be modelled using energy based failure theories using the NCCT specimen

55 Future work Longer crack lengths, more comprehensive propagation values within the R-curve 55

56 Future work 56

57 Future work Scaled Bentley car bonnet for component level testing of the spread tow carbon / S2-glass fibre hybrid 57

58 Future work Vectran/Epoxy (MTM57) tested using the same configuration due to low compressive strength. 25mm total thickness 58

59 Tomas Katafiasz With thanks to: Iannucci, L. and Greenhalgh, E. 59

60 10mm thick S2-Glass, 10mm crack length achieved before rear end compression Maximum strain failure criterion 60

61 61