Onr (Italy) Review On Blast Resistance

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Onr (Italy) Review On Blast Resistance

  1. 1. MULTIFUNCTIONAL MATERIALS: SHOCK, DURABILITY AND BLAST RESISTANCE PROFESSOR DAVID HUI UNIVERSITY OF NEW ORLEANS
  2. 2. OUTLINE Background University of New Orleans (UNO) work relates to developing three functional properties in composite materials: (1) Energy absorption (2) blast protection and (3) durability UNO applied nanotechnology-based solutions through the utilization of nanomaterials that dissipate a substantial fraction of the shock/blast energy that is received We analyzed the mechanisms Experiments with nano-particle filled composites in linear impact (Hopkinson Bar) Experimented with CNT reinforced damping (Vibration) Applied holography and laser vibrometry for experimental records We have proven nanoparticle-based energy absorption technology Energy absorption was achieved by providing large energy sink by sources for friction and slip-stick motion at interfaces of matrix and nanoparticle.
  3. 3. BACKGROUND OF UNO’S NANO-PARTICLE BASED COMPOSITES RESEARCH FOR NAVY
  4. 4. WHAT US NAVY WANTS FOR THE SHIPS? Lighter Stronger Faster The above are the three mantras for the Navy’s R&D search for new materials
  5. 5. NEW MATEIALS SHOULD ENABLE THE NAVY TO HAVE SHIPS Quickly deployable Carry Larger Payloads Survive threats in high seas These would be possible if materials with specific property improvements are introduced
  6. 6. Navy’s new materials of the future NANO-COMPOSITES In all their varieties as Smart Adaptive Multifuctional Etc Etc
  7. 7. MULTIFUNCTIONAL MATERIALS
  8. 8. NAVY IS CHANGING NEW TECHNOLOGIES FOR NAVY ALL VARIETIES OF COMPOSITES Smart, Adaptive, Nano, Multifunctional, Graded FRICTION STIR WELDING Avoids HAZ NEW HULL DESIGNS Advanced composite Double Hull (1998) Double M Hull (2004) NEW JOINT DESIGNS Composite to Metal
  9. 9. Technology show case Swedish all-composite STEALTH ship – First in the world Max length possible with today’s technology : 209 ft Ships longer than 400 ft can not be built with composites Because of lower stiffness New ship double hull concept New hybrid hull concept The bow and stern made of Composite, the mid part stainless steel Metal-composite jointing is in issue
  10. 10. TECHNICAL DISCUSSIONS -BASICS- SOLID IMPACT ON A MULTI-LAYERED SOLID MEDIA 1 dimensional problem : FORCE F = PA V v IMPACTOR VELOCITY =V IMPACT ENERGY = 0.5MV2 Particle velocity =v S Stress Pulse Energy = cv (unidirectional stress wave propagation theory) IF IMPACTOR IS CYLINDRICAL SOLID where: AND GAS PROPELLED, THEN = Density IMPACT ENERGY = PAS v = particle velocity WHERE c = stress wave velocity = (E/ )0.5 P = PRESSURE E = Young’s modulus A = AREA F2 Note: Transformation of energy from low amplitude F 2 >> F1 force to high amplitude force to cause damage t 2 << t 1 IMPULSE = F1 t 1 = F2 t 2 F1 t t t1 t2
  11. 11. IMPACT ---BASICS F2 Note: Transformation of energy from low amplitude F 2 >> F1 force to high amplitude force to cause damage t 2 << t 1 IMPULSE = F1 t 1 = F2 t 2 F1 t t t1 t2 ENERGY OF THE IMPACTOR = (1/2)MV2 ENERGY OF STRESS WAVE = [A/( C)] (1/2)MV2 = [A/( C)] The trick to make a structure to survive impact is to make the high amplitude F2 (stress) transform to low amplitude F1 so that the material’s strength is not exceeded. Modifying materials by using nanotechnology achieves it by dispersing the stress wave amplitude very rapidly
  12. 12. Dutta-Tech Multiple Impedance Pressure Bar (MIPB) MULTILAYER WAVE PROPAGATION – Increased Number Of Interfaces Cause Decrease in Propagating Stress Amplitude Impedance Z = ρc/g Steel PC AL brass steel Strike r Light Gas Materials of different impedences Pressure SG SG SG SG SG = Strain Gage
  13. 13. Multiple layer shock propagation problem
  14. 14. Dutta-Tech DUTTA HYPOTHESIS FOR IMPEDANCE GRADIENT WHICH CONSIDERS INFINITE NUMBER OF LAYERS Interface Damage Multiple Plate Impedance Mismatched Barrier/Armor Impedance graded No Interfaces Barrier/Armor
  15. 15. Dutta-Tech Impedance Effect Processing Model from Hopkinson Bar Test Data Energy content of a stress wave pulse: Evaluate Attenuation by comparing wave amplitude Ac t ∫ σ dt 2 And wave energy in incident and in transmitted bar after U ( Energy ) = 0 E The wave has passed through the designed IMG material Where A is the rod area, c is the wave velocity E is the Young’s modulus, sigma is stress, and t is time INCIDENT WAVE AMPLITUDE INCIDENT WAVE ENERGY Stress waveforms in incident bar - test MIX-5B-Direct Energy: stress square- t curve MIX 5B-Direct 50000000 s ) s m s u re (p i^2 6000 4000 40000000 Stress (psi) 2000 S(in) 30000000 ig a q a 0 -2000 S(in) 20000000 -4000 10000000 -6000 -8000 0 0 2000 4000 6000 8000 10000 12000 14000 -10000000 0 2000 4000 6000 8000 10000 12000 14000 Tim (Seconds) e tim (seconds) e TRANSMITTED WAVE AMPLITUDE TRANSMITTED WAVE ENERGY Transmitted stress wave Energy: stress square - t curve Mix 5B-Direct MIX 5B Sigm square (psi^2) 50000000 6000 40000000 Stress (psi) 4000 2000 30000000 0 -2000 Sin (t) 20000000 a -4000 10000000 -6000 -8000 0 0 2000 4000 6000 8000 10000 12000 14000 -10000000 0 2000 4000 6000 8000 10000 12000 14000 Tim (seconds) e Tim (Seconds) e Amplitude Attenuation : S(t)/S(in) = 53% Energy Attenuation : S(t)/S(in) = 28%
  16. 16. Nano-technology based energy absorption/damping (After R.S.Lakes, Viscoelastic Solids, Boca Raton, FL, CRC Press)
  17. 17. WHY NANO-COMPOSITES? Look at the Problems of Traditional Ship CarbonSteels: Corrosion Thermal and Electromagnetic Signature Construction by framing and sheathing and welding numerous parts with 100 yrs old designs Labor intensive Numerous Heat Affected Zones (HAZ) stress concentration HAZ’s readily corrdes and fail in fatigue Extensive coating is required Result: Higher building and maintenance costs
  18. 18. WHY NANO-COMPOSITES? Advantages with NANO-Composites: • Higher strength-to-weight ratio • Lower Magnetic Signature • Lower Acoustic Signature • Lower Hydrodynamic Signature • Lower Thermal Signature • Lower Radar Signature • Lower maintenance cost • Parts consolidation in fabrication • Fatigue resistance and durable AND NOW NANO WILL MAKE THE MATERIALS MORE BLAST AND SHOCK RESISTANT •
  19. 19. LINEAR IMPACT STUDY OF A NANOCOMPOSITE IN HOPKINSON BAR
  20. 20. OBJECTIVE Multi-walled carbon nanotube (MWCNT) in a polymer is believed to modify the energy absorbing haracteristics of the resulting nano polymer composites. Our objective here is to find out the efffects of MWCNT contents on the dynamic mechanical properties, including energy absorption characteristics of the resulting Polymer Nano-composites.
  21. 21. Materials The materials were Fabricated at Univ of Mississippi Fabrication 1. Mix different percentages of MWCNT in Nylon 6,6 2. Mold into a panel 3. Cure 4. Cut to lengths
  22. 22. Test Materials Samples:
  23. 23. Hopkinson Bar Apparatus Bars Sample
  24. 24. Strain wave records from the two bars
  25. 25. Governing Equations t Avg strain = ∫ C the specimen = u in ε dt 1 0 1 0 t u 2 = ∫ C0ε 2 dt t 0 u1 = ∫ C0ε1dt Avg stress in the specimen = 0 Avg strain rate in the specimen = Energy Absorbed = L = Specimen length
  26. 26. Results: Effects on peak stress and Energy Absorption
  27. 27. Samples - permanent deformation
  28. 28. STRAIN RATE = SLOPE
  29. 29. STRESS-STRAIN PLOTS 0% 5% 10% Effects of MWCNT % on the modulus (stress-strain slope)
  30. 30. Effect on Energy Absorption 0% 5% 10%
  31. 31. CONCLUSIONS MWCNT Nylon composites are extremely tough. They did not completely fracture under dynamic peak stress of 170 MPa. Internal Damage Predicted from permanent dimensional change. Modes of failure need to be confirmed by SEM MWCNT modified strength, stiffness and energy absorption. Only after smaller addition the properties improved significantly (20% approx). The reasons are being investigated. Nylon is thermoplastic and energy absorbent. Additional work needed with thermoset composites
  32. 32. VIBRATIONAL ENERGY ABSORPTION STUDY IN CNT-FRP COMPOSITES
  33. 33. Nano-particle-reinforced energy absorption: It involves placement of numerous nano particles During impact nanoparticles interact with internal matrix and with one another and thus dissipate energy through momentum transfer and friction
  34. 34. Parameters controlling energy absorption in these materials Particle size Dispersion in matrix Shape Density Texture Coefficient of restitution Coefficient of friction Surface area and conditions Free space around the particles Strain rate
  35. 35. Microstructure of filled composite materials Example of a typical syntactic foam composite material with a relatively low volume fill of micro-spheres. The sphere “ringed” is approximately 50µm µ
  36. 36. Mechanisms of shock and blast energy dissipation syntactic homogenous material foam composite material K and G representative hydrostatic shear load volume pressure load Principle of homogenisation method for syntactic foam composite materials
  37. 37. Dispersion of lightweight spherical fillers 30 wt.% SiO 120µm microspheres (Optic. 50x) 5 wt.% SiO 1µm mesospheres (Optic. 50x) 5 wt.% SiO 10nm nanospheres ( Optic. 50x) 30 wt.% SiO 120µm microspheres (500x) Fractured surface of 5 wt.% SiO 1µm (2000x) 5 wt.% SiO 10nm nanospheres (2000x) Better dispersion Fractured surface of SiO microspheres (700x) 5 wt.% SiO 1µm mesospheres (8000x) of nanofillers 5 wt.% SiO 10nm nanospheres (20000x)
  38. 38. Properties of interphase layer Effective thickness of interphase layer Approaches to control the interphase layer Chemical dispersant / surfactant to achieve dispersion and effective thickness of the layer Electrostatic ultrasound 30nm thickness of interphase layer 50-80 vol.% treatment concentration of nanoparticles High shear force mixing to prevent agglomeration 100nm thickness of nanoparticulates of interphase layer 10-30 vol.% concentration of nanoparticles
  39. 39. Single-walled nanotube-epoxy composite
  40. 40. Computationally performed Pull out test
  41. 41. Composite Materials, Experimental Samples manufactured manually by meltmixing nanotubes and polymer by extrusion process Investigated the effects of different orientations of carbon nanotubes (CNT) Applied multiple stress rates Viewed results by holography technique High strain rate was produced by Bruel and Kjaer (B&K) vibration system Energy absorption capacity was measured by damping capacity measurements
  42. 42. Nanotube-FRP Experimental (Contd) CNT orientations were controlled by extrusion rate We measured : frequencies, mode shapes, and damping at each mode by the B&K laser vibrometry Computer System Laser vibrometer Electro- Clamped dynamic Sample exciter
  43. 43. Density, kg/m3 (Temp.=25C) 0 200 400 600 800 1000 1200 1400 ep IP 40 ox 29 20 w y 0 w t.% V er 1125 t.% ifl Si e 30 N O w i-c ,5 x Pure oa 00 epoxy 1045 t.% te µm 20 N d, i-c 12 w o 0µ 1136 t.% ate m 40 VS d, 1 866 w 20 t.% 550 µm VS 0, 1 828 20 55 00 µm w 00 ,1 t.% 772 00 40 D 2 w 32 µm w ,1 Microscale t.% t.% 20 Ex D3 µ pa 2, 1 m nc 20 el 5 , 1 µm w 740 726 740 t.% 0-4 0µ 10 Si O m w t.% 300 1- 5µ 2. 5 Si O m w 1- 1150 t.% 5µ 5 Si m w C 1210 t.% 50 Mesoscale 2. nm 5 Si C w t.% 50 1080 nm 5 Si O w 1060 t.% 15 2. 5 Si nm O w t.% 15 nm 5 Si O w 1030 1010 t.% 10 2 w Si nm O t.% 7 w 1050 t.% 10 2 m nm Nanoscale w es Si O t.% oS 990 m iO 10 2 ,8 nm w es t.% oS nm 930 m iO po es ,4 r oA nm e 790 lS po 2 i, re w 8n t.% m 730 5 C po w N re t.% T 10 750 C 0n Density (weight) of foam composites N m T 10 730 0n m 690 Carbon Nanotubes
  44. 44. Loss factor, tan δ (Temp.=110C) 0 0.2 0.4 0.6 0.8 1 1.2 ep IP 40 ox 29 20 w y 0 wt t.% V 0.02 .% er Si le if 30 N O w i- c ,5 x Pure 0.3 Resin t.% oa 00 Epoxy te µm 20 N d, i- c 12 w o 0.26 t.% ate 0µ d, m 01/03/2010 40 VS 12 w 0.32 t.% 550 0µ 0, m VS 10 0.27 20 55 0µ w 00 m t.% ,1 0.38 40 00 D3 2 µm wt wt.% 2, 1 .% Microscale 0.32 20 Ex D3 µm pa 2, 0.4 nc 12 el 0 5 , 1 µm wt 0- .% 0.35 40 10 Si µm w O t.% 1- 0.25 5µ 2. 5 Si O m w 1- 0.45 t.% 5µ 5 Si m w C 0.4 t.% 50 Mesoscale 2. nm 5 Si C w 0.35 t.% 50 nm 5 Si O w 0.38 t.% 15 2. 5 Research Office Si nm w O 0.41 t.% 15 nm 5 Si O w 0.48 t.% 10 © The University of Sheffield / 2 w 7 Si nm O t.% w 0.8 elevated temperature t.% 10 2 m nm e Nanoscale w Si O 1 t.% soS iO 10 2 m ,8 nm w es oS nm t.% 0.9 m iO po es ,4 r oA nm e 0.95 lS po 2 i, re w 8n t.% m 0.98 5 CN po re w t.% T 1 0.83 00 CN nm T Energy dissipation properties of foams at 10 0.65 0n m 0.55 Carbon Nanotubes
  45. 45. Damping prediction 9 10 Modulus (Pa) 8 10 7 10 6 10 0.6 A + glas s ____ SWCNT + polymer A A + poly B + glas s + poly Loss factor - - - MWCNT + polymer A 0.4 CNT+ polymer B B + poly - - CNT+ polymer A + ceramics 0.2 0 0 20 40 60 80 100 120 Tem perature (° C) Mechanical and damping and Properties at 10 Hz: 5wt% CNT-reinforced balloon- BOUNDARY MESHLESS based foams. The peak damping occurs around 100°C for CNT-reinforced FORMULATION FOR ° polymer balloon-basedOF SOLIDS DEFORMATION syntactic 45
  46. 46. Strength of Syntactic Foams
  47. 47. Shock resistance of foam composite materials
  48. 48. Nanotube-FRP Experimental (Contd) Resonant frequency was determined from the peaks of the frequency response curves Each mode shape was the characteristic of the specific NT-FRP A finite element model was used to determine displacements and stresses for each orientation of the CNT with respect to loading direction. Vibration Vibration Load Load (a) (b) (c) Nanoparticle orientation: (a) CNT along the load direction P, (b) chaotic distribution of CNT, and (c) perpendicular CNT to the load direction.
  49. 49. Nanotube-FRP Experimental (Contd) Modes of vibration of the NT-FRP samples by holography: a b c d e f CNT-reinforced samples, viewed by holography and in color computer imaging for different CNT orientations: (a) CNT along the load direction P, (b) chaotic distribution of CNT, and (c) perpendicular CNT to the load direction
  50. 50. Nanotube-FRP Experimental Results Frequency was varied from 200 to 4000 Hz Twelve natural frequencies were identified Signals were noisy below 400 Hz Single matrix had better coherence than the CNT-FRP’s Variation between tests and finite element prediction of frequencies was within 10% Clamping conditions influence variations Resonance Frequencies Obtained by Laser Vibrometry at Room Temperature ω, along CNT- ω, perpendicular ω, Polymer Mode # reinforced %, Diff. CNT-reinforced %, Diff. matrix (Hz) polymer (Hz) polymer (Hz) 1 186 112 39,8% 132 29.0% 2 506 254 49.8% 411 18.8% 3 860 544 36.7% 546 36.5% 4 1206 856 29.0% 974 19.2% 5 1,658 1,211 27,0% 1,346 18.8% 6 1,924 1,612 16.2% 1,574 18.2% 7 2,504 2,016 19.5% 2,182 12.9% 8 2,934 2,123 27,6% 2,176 25.8% 9 3,624 3,086 15.1% 3,560 1.8% 10 3,918 3,134 20.0% 3,545 9.5%
  51. 51. ANALYSIS- Interphase layer model : Assumption The dissipated energy, via interfacial movement of nanotube and polymeric material, is linked with the local cohesion and adhesion phenomena between the filler/matrix interface. Consider the equivalent shear force and the differential displacement between tube and matrix (after Koratkar et al 2002, and Odegard 2004) η = Loss factor Udiss = Energy Dissipation r = radius of nanotube =10-100nm l2 = length of nanotube
  52. 52. ANALYSIS- Interphase layer model (Contd) Strain between nanotube and matrix material ( 2 ): Where R = radius of the representative volume V G = Shear modulus E eq = Equivalent modulus of nanotube = 2(l/t)Eg And
  53. 53. ANALYSIS- Interphase layer model (Contd) Stress in composite materials is associated with energy dissipation and is given by:
  54. 54. Comparison of damping behavior Perpendicular CNT- Polymer Along CNT-reinforced reinforced polymeric matrix polymeric material material Mo Damping Damping Increase, Damping Increase, de factor, Q factor, Q % factor, Q % 1-2 339 543 60,2 412 21,5 3-4 811 1402 72,9 1253 54,5 5-6 1193 1616 35,5 1345 12,7 7-8 696 907 30,3 823 18,2 9- 10 1783 2341 31,3 1896 6,3
  55. 55. Nanoindentation of blast-resistant materials
  56. 56. Sample preparation for nanoindentation Typical microtomed nanocomposite samples mounted on magnetic steel disks to hold the sample magnetically. Polishing of the microtomed section of sample is not desireable due to a risk of particle failure. Notes to the rightside figure. Steel disk diameter 15mm. Heating stage used on the NanoIndenter. Samples are thin to control the surface temperature. Samples are held by springs. Size of heated plate approx.
  57. 57. Nanoindentation of multilayered and nanomaterials at interphase Several samples mounted on standard stage; Area 15x15cm; height 0cm - 3cm; weight <10kg
  58. 58. Nanoindentation at statics Typical indentation load-displacement curves for fibre, matrix and the transition Variation of elastic modulus across the region at a maximum indentation depth of matrix-interphase-fibre 60 nm Source: Jang-Kyo Kim, Man-Lung Sham. Composites, part A 32, 2001. 607 – 618
  59. 59. Surface topography of composite materials SiO sphere-filled composite material sample; polymer matrix (epoxy) with dispersed inclusions (lightweight and stiff hollow SiO spheres) on Surface Topography at the filler- left corner, improving blast matrix interphase point, showing a resistance of matrix. step change in mechanical properties at the interphase;
  60. 60. Nanoindentation results
  61. 61. Modulus Mapping of blast-resistant materials
  62. 62. Prediction of Energy Dissipation at Impact Stress Impact stress of centrally notched specimen was simulated by MSC.Visual Dytran/LS.Dyna for Windows XP.
  63. 63. Benefits of filled nanocomposites 1.Contains organically-treated, fillers that disperses evenly throughout resin. 2.Reinforcement efficiency is achieved at low concentrations (3- 5%) that has a small cost in terms of specific gravity. 3.Stiffness comparable to a 20-30% load of a standard mineral filled compound. 4.Vibration damping and heat resistance considerably increased in nanocomposites. 5.Lower loading levels (2-8 wt.%) help maintain resin transparency. 6.Available for injection molding, extrusion (sheet or film), and blow molding. 7.Other benefits of nanocomposite include: lower gas permeability, good surface appearance, dimensional stability, and lower heat release.
  64. 64. Conclusions and general remarks NT-FRP show a great promise of energy absorption as clear from the study of their damping characteristics The nano structure in which the polymers tend to form large- diameter helices around NT favors strong matrix bond Depending on orientations the NT increases or decreases the bond strength, fracture strength or damping by 10-20% More work is needed to characterize the effects of SWNT, MWNT, Fullerene, BN, or SiC nanotubes, dispersion and orientation effects, Multiscale vibration damping modeling needs to be refined Both computational and experimental benchmarks need to be improved
  65. 65. Refereed Journal Articles published with respect to this work 1. M. Kireitseu, G. Tomlinson, D. Hui, L. Bochkareva. Dynamics and Vibration Damping Behavior of Advanced Meso/Nanoparticle-Reinforced Composites. Journal of Mechanics of Advanced Materials and Structures, 14(8), 2007, 603-617. 2. M. Kireitseu, D. Hui, G. Tomlinson. Advanced shock-resistant and vibration damping properties of nanoparticles-reinforced composite material, Jrnl. of Composites Part B 39(1), 2008, 128-138. 3. Lurie S, Hui D, Kireitseu M V, Zubov V, Tomlinson G R, Bochkareva L, Williams R A. “Computational Mechanics Modelling of Nanoparticle-Reinforced Composite Materials across the Length Scales”. Int. Journal of Computational Sc. and Engineering, 2 (3-4), 2006, pp. 228-241. 4. M. Kireitseu, V. Kompiš, D. Hui, G. Tomlinson, L. Bochkareva, S. Lurie. Modelling of Strength of Nanoparticle-Reinforced Materials and their Applications. Jrnl. of Science & Military, 2 (1), 2006, 1-6. 5. D. Hui, M. Kireitseu, G.R. Tomlinson, V. Kompis. Advanced Design Concepts and Modelling of Composite Materials in Emerging Applications. Advances in Science and Technology, 50, 2006, pp. 124-130. 6. M.V. Kireitseu, D. Hui, K.T. Lau, Viscoelastic behaviour and vibration damping properties of epoxy based composite filled with coiled carbon nanotubes, Journal of Nanomaterials, Hundawei Publ. House (submitted, August 2008)

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