STRUCTURAL EVALUATION OF THICK COMPOSITES FOR MARITIME APPLICATIONS A i th Nanayakkara Asintha N kk Maritime Division Unclassified Outline C it for f maritime iti li ti • Composites applications • Thick composites and failure • DSTO Generic Foil • Materials • Manufacturing • Static/Fatigue testing • Finite element studies • Future work Unclassified Composite Properties • • • Weight reduction Non‐magnetic Corrosion resistant Youngss Modulus (G GPa) Why composites? Ni-Al-Bronze E11 UD carbon-epoxy 100 E11 UD aramid-epoxy Mn Al Bronze Mn-Al-Bronze E11 UD glass-epoxy E22 UD carbon-epoxy 10 E22 UD glass-epoxy E22 UD aramid-epoxy 1 1 2 3 4 5 6 3 Density (g/cm ) 7 8 Performance Shape‐adaptive behaviour Increased propulsion efficiency • Increased range Increased range • • bend-twist coupling p g Unclassified Why composites ? Design • • • • Large choice of fibres Large choice of fibres Structural health monitoring Ability to replace components Reduce maintenance Reduce maintenance Carbon Kevlar Manufacture • • Near‐net‐shape processing Lower cost production Unclassified Composites in Marine Applications • • • • • Minehunter Patrol boats Hovercraft Surface combatants Submarines SOURCE: http://www.navy.gov.au http://www.naval-technology.com/projects/skjold/ HMASSOURCE: Gascoyne • Bulkheads B lkh d • Hydrodynamic Control surface • • • • Rudders Machinery Heat exchangers Pumps/pipes/ducts SOURCE: http://www.navy.gov.au Submarine Unclassified Research and development pathway • Hobart Class AWD SOURCE: http://www.navy.gov.au A li ti Applications ~1:1 Large Foils Small Foils Structural Static/Fatigue Testing ~1:10 • Failure Modes • Si and Size dS Scale l Eff Effects t • Manufacturability • Material Properties • Coupon Tests Unclassified Fundamental Science DSTO Generic Foil Dimensions and Loading Conditions • Large foil allows for a range of techniques and numerical tools to be developed before being applied to real applications • Reduced problem: • Contains features such as hydro-profile hydro profile, taper and scale Unclassified Potential failure modes Delamination Delamination D l i ti iin a composite it laminate Compressive Failure Kink bands i fib in fibres Bending of curved beams Free edges wavy plies Tensile Failure Bending stresses External ply p y drop-off p Unclassified Fatigue DSTO Generic hydrofoils Foil Skin Material Core Material Manufacture method Mass (kg) Density (g/cm2) Foil-1* Glass-Woven, GlassMat Glass-Woven VARTM 34.1 1.90 Foil-2 Glass-Woven, Gl W GlassGl Mat Glass-Woven Closed Cl d mould ld RTM 67.8 1.90 Foil-3 Carbon 500UD, Carbon-500UD, Carbon-400DB, Glass-Mat Glass-Quad Closed Cl d mould ld RTM 57.8 1.62 Foil-4 Carbon 450UD, Carbon-450UD, Carbon-400DB, Glass-Mat Glass-Quad Closed Cl d mould ld RTM 56.5 1.58 * Onlyy half foil made Unclassified Fabrics Glass Basket Glass Mat (130 g/m2) (780 g/m2) Carbon 450UD (450 g/m2) Glass Quad Glass Biax Carbon 500UD Carbon DB (1430 g/m2) (600 g/m2) (500 g/m2) (400 g/m2) Unclassified Foil profile Glass-Quad Glass Quad 36% Resin Glass-Basket 1% Glass-Mat 6% (R d) C (Red) Carbon b DB 25% (Blue) Carbon UD 22% Unclassified Foil profile Tip Root Unclassified Foil Manufacture – Composite Modeller Abaqus Unclassified Composite Modeller Abaqus - Ply 20 Unclassified Composite Modeller Abaqus - Ply 40 Unclassified Composite Modeller Abaqus - Ply 50 Unclassified Composite Modeller Abaqus - Ply 55 Unclassified Composite Modeller Abaqus - Ply 60 Unclassified Composite Modeller Abaqus - Ply 65 Unclassified Foil Manufacture Unclassified Infusion Half foil VARTM • • • • Closed-mould RTM with combined vacuum and pressure Kinetix R118 resin + long pot life H103 hardener Kineti Approximately 11 kg of resin required to make a half foil Infusion process took approximately 60-90 min Room temperature cure overnight; post-cured at 60ºC for 6h 80ºC for 15h p g p Unclassified Bonding Surfaces were lightly sanded and cleaned with acetone. Fine netting material was used to help maintain a consistent bondline thickness Toughened epoxy paste adhesive Techniglue-HP R15 Post cure was performed at 50ºC. The achieved b bond d liline thi thickness k was approximately i t l 1 mm. Unclassified Guide fixtures and clamps ensured that the top half of the foil did not move during the bonding process. Finished blade Unclassified Finite Element Analysis BC: Clamped Load AIM: • Investigate composite modelling techniques • Use Composite Modeller ad-on • Element studies • Determine deflections • Failure criteria • Boundary condition (clamped) • Distributed load 100mm from foil tip; 50kN • C3D8 solid elements • Ply-by-ply Pl b pl model • Deflection; approximately 109mm • No No. of elements; 770370 Unclassified Longitudinal stresses z • Stresses are at maximum in carbon layers; just beneath glass surface Stress; MPa Unclassified x y Longitudinal stresses Max stresses are in carbon unidirectional layers in tension Carbon DB Glass-Mat Glass-Quad z y Stress; MPa Unclassified Longitudinal stresses Max stresses are in carbon unidirectional layers in compression Glass-Mat Carbon DB Stress; MPa Unclassified z Glass-Quad y Transverse stresses Stress; MPa z x y • Transverse stresses at a maximum on the surface • Max stresses are along the thickest region Unclassified Transverse stresses Stress; MPa Carbon UD Glass-Mat Glass-basket C b DB Carbon Glass-Quad z y Unclassified Interlaminar shear stresses Stress; MPa • Interlaminar stresses peaked towards the geometric centre near foil f il tip ti • Interlaminar stresses rose in ply l drop d region i Unclassified z y Finite element studies: Conclusions • Tip deflections of approximately 10cm • Maximum longitudinal stresses in Carbon UD layers • Maximum transverse stresses on surface of foil • Maximum shear stresses near ply drop regions • Failure anticipation via delamination in structural plies • Possible kinking/compressive failure in lower side of blade Unclassified Outcomes • Overview of generic hydrofoil program • Successful manufacture of a thick composite part • Successful infusion processes • Finite element studies; high interlaminar stresses in ply d drop regions i and d ttowards d th the roots t Unclassified Future work and structural testing •Full scale static/fatigue tests •Phase Phase I: static tests; Phase II: Dynamic tests; Phase III: overload •Test Test results will be used to: • validate numerical modelling tools, • understand fatigue failure failure, develop NDE techniques for detecting fatigue induced defects • evaluating strain sensing systems. Unclassified Future work and structural testing • Test range of strain and deflection sensors: fibre optics and strain guages • Failure analysis on foil • Coupon tests; in-plane, throughthickness and fracture • Introduce failure criteria for FE Unclassified Acknowledgements • • • • • • • Andrew Phillips Nigel St John Russell Cairns Gary y Simpson p Gary Mathys Sarina Russo Jeff Heath Unclassified THANK YOU OU QUESTIONS? Unclassified
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