Concept Optimal Design of Composite Fan Blades

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Concept Optimal Design of Composite Fan Blades

  1. 1. Concept Optimal Design of Composite Fan BladesJ. S. Rao, S. Kiran and B. Bombale Presented by Dr. Robert Yancey yancey@altair.com Altair Confidential
  2. 2. Objectives• Composite Design of given baseline metallic (Ti) fan blades.• At operating speed • baseline maximum strain in the vane is maintained • weight reduction is taken as the objective function.• Phase I: Ply shape optimization• Phase II: Ply thickness optimization• Phase III: Ply order optimization.• Goal: weight savings without affecting performance of engine blade. Altair Confidential
  3. 3. Composites Overview within HyperWorks CAD Mfg Simulation Interoperability Interoperability HyperMesh (Traditional Zone & Modern Ply Based Composites Pre-Processing) Realizations Visualizations (Export Ply Based Models to (Visually verify the Math Model) Solver Zone Based Models) OptiStruct/RADIOSS (Composites Design Optimization & Finite Element Analysis)HyperLaminate Solver HyperView FEA Solver (Composites Post-Processing Interoperability(Classical Lamination Theory) & Failure Analysis) Altair Confidential
  4. 4. Design Synthesis with Isotropic Topology • Altair’s Early Focus with Optimization Technologies Density = 1 Isotropic Solid Topology Isotropic Shell Topology Design Variables = Element “Density” Density = 0 0/1 Optimization E/E0 1 (r/r0)p • Benefits 1 r/r0 • Design Synthesis - Designs driven by physics of the problem • Typically Reduced Weight, Increased Robustness, Decreased Cycle Time Time Allowed Parameter (Weight) Critical Design Traditional Methods OptiStruct Time Altair Confidential
  5. 5. Isotropic Free-Size Optimization• Isotropic Free-Size  Compliment to Isotropic Shell Topology• Design Variables = Element Thickness (NOT Element “Density”)• Isotropic Free-Size vs. Isotropic Shell Topology Example Cantilever Plate Problem Isotropic Shell Topology Isotropic Free-SizeShell Isotropic Solid TopologySolid• Launching Platform for Composite Design Synthesis• Industry Leader in Free-Size Technology with Manufacturing Constraints Altair Confidential
  6. 6. Composite Free-Size Optimization • Isotropic Free-Size vs. Composite Free-Size Continuous Thickness between T_Lower and T_Upper 45 T = Ply4 (opti) 90 T = Ply3 (opti) 45 T = Ply4 (nom) T = Lower T = Upper PCOMP -45 T = Ply2 (opti) T_Total 90 T = Ply3 (nom)PCOMP -45 T = Ply2 (nom) After Optimization PSHELL T = Lower 0 T = Ply1 (opti) T_0 T = Upper 0 T = Ply1 (nom) sym sym • Captures Coupling Between Total Thickness and Ratio of Ply Orientations (%0 %45 %90) by Updating Individual Ply Thickness • Stacking Sequence Effects Captured by SMEAR Technology • A = Stacking Sequence Independent • B=0 • D = At2/12 – Stacking Sequence Independent • Unique Composite Design Synthesis – “Growing of Plies” Altair Confidential
  7. 7. Composite Free-Size – What are the Ply Shapes? Composite Free-Size Optimization Definition • Consider 0/45/-45/90 Plies • Min/Max Individual Ply Angle Percentage 10% / 60% • Balance 45/-45 Plies Cantilever Plate Problem Composite Free-Size Isotropic Free-Size Isotropic Solid TopologyShell 45/-45Deg Ply Thickness 90Deg Ply Thickness Composite Free-Size Optimization Results • Grow or Synthesizes Ply Shapes • Laminate Regions = Boundaries of Each Ply 0Deg Ply Thickness • Requires Ply Based Modeling Techniques Altair Confidential
  8. 8. Composite Design Synthesis with Ply Based Modeling 45/-45Deg Ply Shapes 90Deg Ply Shapes 0Deg Ply Shapes Altair Confidential
  9. 9. Composite Size Optimization – How Many Plies?• Stack Synthesized Ply Shapes Size Results• Define Manufacturing Constraints • Min/Max Ply Angle Percentages Free-Size Results • Balanced Laminates 90 Deg (2 Plys)• Define Optimization Targets 45 Deg (2 Plys) -45 Deg (2 Plys) • Stress/Strain Targets 0 Deg (2 Plys) • Deformation/Buckling Targets 90 Deg (2 Plys) • Minimize Mass 45 Deg (2 Plys)• Perform Size Optimization to -45 Deg (2 Plys) Determine Number of Plies Required to Meet Engineering 0 Deg (2 Plys) Optimization After Targets 90 Deg (2 Plys) 45 Deg (2 Plys) -45 Deg (2 Plys) 0 Deg (2 Plys) 90 Deg (2 Plys) 45 Deg (2 Plys) -45 Deg (2 Plys) 0 Deg (2 Plys) Altair Confidential
  10. 10. Composite Shuffling – What is a Probable Stacking? • Shuffling Size Results Shuffle Results • Defines “Probable” Stacking Sequence • Obeys Manufacturing Constraints • Manufacturing Constraints • Min/Max Total Laminate Thickness • Min/Max Ply Thickness • Min/Max Ply Angle Percentage • Balanced Ply Angles After Optimization • Constant Ply Thickness Altair Confidential
  11. 11. Unique Composite Design Methodology• Design Synthesis (Concept Design) Technologies • Isotropic Solid Topology • Isotropic Shell Topology • Isotropic Free-Size Complimentary Technologies • Composite Free-Size• Design Tuning Technologies • Isotropic Size/Shape Optimization • Composite Size/Shape Optimization • Composite Shuffling Optimization• Unique Composite Design Synthesis Methodology 1. Topology – What is the Shape of the Part? 2. Composite Free-Size – What are Shapes of the Plies that make up the Part? 3. Composite Size/Shape – How many Plies required to meet Engineering Targets? 4. Composite Shuffling – What is a Probable Stacking Sequence to meet Mfg Considerations? Altair Confidential
  12. 12. Baseline Model• Titanium blades• E = 105 GPa, m = 0.23, r = 4.429×10-9.• 18 blades• Total mass excluding hub = 3.722 Kg.• Length 200 mm• Constant chord 65 mm• 84o pre-twist• 15000 rpm. Altair Confidential
  13. 13. Stress Analysis Altair Confidential
  14. 14. Composite Optimization Stages • Phase 1: Ply Shape optimization • Phase 2: Ply Thickness optimization • Phase 3: Ply Order optimization Altair Confidential
  15. 15. CFRP Properties Young’s modulus (in fiber direction) E11 = 115 GPa Young’s modulus (perpendicular to fiber direction) E22 & E33 = 15 GPa Shear modulus G = 4.3 GPa Density = 1500 Kg/mm3 Volume fiber fraction = 0.5 Altair Confidential
  16. 16. Composite FE Model with 5 Stacks Altair Confidential
  17. 17. Base Laminate Stack 1 Altair Confidential
  18. 18. Base Laminate Stack 2 Altair Confidential
  19. 19. Base Laminate Stack 3 Altair Confidential
  20. 20. Base Laminate Stack 4 Altair Confidential
  21. 21. Base Laminate Stack 5 Altair Confidential
  22. 22. Maximum Principal Strain Contour Altair Confidential
  23. 23. Free Size or Topology Optimization • Stacks 1 and 5 are 1.75mm thick • Stacks 2 and 4 are 4.25 mm thick • Middle Stack 3 is taken with the maximum thickness 5.75 mm • After the Ply Shape Optimization, the superply shape for each Ply Bundle is found. There are 20 Ply Bundles; 0o, +45o, -45o and 90o for each of the five stacks. • The super plies for 0o, +45o, -45o and 90o are given in next slides Altair Confidential
  24. 24. Free Size Optimization for 0o Super Ply Altair Confidential
  25. 25. Free Size Optimization for +45o Super Ply Altair Confidential
  26. 26. Free Size Optimization for -45o Super Ply Altair Confidential
  27. 27. Free Size Optimization for 90o Super Ply Notice maximum thickness in each super ply in middle stack 3 is 1.438 mm, total being 5.75 mm Altair Confidential
  28. 28. So far• A review of the design process up to now reveals that we established the optimum ply shape and patch locations in phase 1 (free size optimization) and subsequently optimized the ply bundle thicknesses in phase 2 (ply bundle sizing optimization), allowing us to determine the required number of plies.• These ply bundles represent the Optimal Ply Shapes (Coverage Zones). Altair Confidential
  29. 29. Total Thickness of 0o Ply after Size Optimization Stack 1 0o ply thickness 0.414 mm achieved by four plies stacked Altair Confidential
  30. 30. Total Thickness of +45o Ply after Size Optimization Altair Confidential
  31. 31. Total Thickness of -45o Ply after Size Optimization Altair Confidential
  32. 32. Total Thickness of 90o Ply after Size Optimization Maximum thicknesses in the middle patch at the root 1.509, 1.344, 1.344 and 1.474 mm respectively for 0o, +45o, -45o and 90o Max thickness = 1.509+1.344+1.344+1.474 = 5.671 mm Altair Confidential
  33. 33. Stacking Sequence for Stack 1: 13 Plies Altair Confidential
  34. 34. Stacking Sequence for Stack 2: 16 Plies Altair Confidential
  35. 35. Stacking Sequence for Stack 3: 16 Plies Altair Confidential
  36. 36. Stacking Sequence for Stack 4: 4 Plies PLY THK 41101 0.986 maximum thickness in this stack is 3.822 mm 42101 0.931 43101 0.931 44101 0.974 Altair Confidential
  37. 37. Stacking Sequence for Stack 5: 4 Plies PLY THK maximum thickness in this stack is 1.649 mm 51101 0.4164 52101 0.4085 53101 0.4085 54101 0.4164 Altair Confidential
  38. 38. Maximum Principal Strain in Optimized Vane Maximum principal strain of the optimized composite blade is 0.00364 same order as baseline metallic blade 0.00326. Note that there is still considerable margin for a composite because of its strength. Weight savings of 27%/ Altair Confidential
  39. 39. Conclusion• A procedure for obtaining a composite fan blade from the given metallicblade is presented.• The steps in Composite ply optimization of the baseline composite arepresented. Five stacks are adopted here. The super plies and drop off pliesrequired are shown.• A sizing optimization is performed for minimum weight. Manufacturingconstraints are included in the sizing optimization. Total thicknesses of 0o,+45o, -45o and 90o plies are presented in all five stacks.• Finally a Ply-Stacking optimization is performed taking into accountmanufacturing constraints. The stacking in all five stacks is shown.• The weight savings of 27% was achieved for the structural load caseconsidered. The maximum strain is kept to be of the same order in the finaloptimized vane as that in the metallic blade baseline, though the compositecan take much higher value. Altair Confidential
  40. 40. Thank YouAny Questions? Altair Confidential

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