concept optimal design of composite fan blades
Post on 12-Sep-2014
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TRANSCRIPT
Altair Confidential
Presented by
Dr. Robert Yancey
Concept Optimal Design of Composite Fan Blades
J. S. Rao, S. Kiran and B. Bombale
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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.
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Composites Overview within HyperWorks
CAD
Interoperability
Mfg Simulation
Interoperability
HyperMesh (Traditional Zone & Modern Ply Based
Composites Pre-Processing)
Visualizations (Visually verify the Math Model)
OptiStruct/RADIOSS (Composites Design Optimization &
Finite Element Analysis)
HyperView (Composites Post-Processing
& Failure Analysis)
HyperLaminate Solver (Classical Lamination Theory)
FEA Solver
Interoperability
Realizations (Export Ply Based Models to
Solver Zone Based Models)
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• Altair’s Early Focus with Optimization Technologies
• Benefits
• Design Synthesis - Designs driven by physics of the problem
• Typically Reduced Weight, Increased Robustness, Decreased
Cycle Time
Design Synthesis with Isotropic Topology
Isotropic Solid Topology Isotropic Shell Topology
Density = 1
Density = 0
E/E0
r/r0
(r/r0)p
1
1
Time
Cri
tica
l D
esig
n
Par
amet
er (
Wei
ght)
Traditional Methods
OptiStruct
Time Allowed
Design Variables = Element “Density”
0/1 Optimization
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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
• Launching Platform for Composite Design Synthesis
• Industry Leader in Free-Size Technology with Manufacturing Constraints
Cantilever Plate Problem
Shell
Solid
Isotropic Shell Topology Isotropic Free-Size
Isotropic Solid Topology
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Composite Free-Size Optimization
• Isotropic Free-Size vs. Composite Free-Size
• 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”
T = Lower T = Upper PSHELL
T = Ply3 (opti) 90
T = Ply2 (opti) -45 T = Ply4 (nom) 45
PCOMP
sym
T = Lower T = Upper
T = Ply3 (nom) 90
T = Ply2 (nom) -45
T = Ply1 (nom) 0
T = Ply4 (opti) 45
PCOMP
sym
T = Ply1 (opti) 0 T_0
T_Total
After Optimization
Continuous Thickness between T_Lower and T_Upper
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Composite Free-Size – What are the Ply Shapes?
Cantilever Plate Problem
Shell
Isotropic Free-Size
Composite Free-Size Optimization Definition
• Consider 0/45/-45/90 Plies
• Min/Max Individual Ply Angle Percentage 10% / 60%
• Balance 45/-45 Plies
Isotropic Solid Topology
0Deg Ply Thickness
90Deg Ply Thickness
45/-45Deg Ply Thickness
Composite Free-Size
Composite Free-Size Optimization Results
• Grow or Synthesizes Ply Shapes
• Laminate Regions = Boundaries of Each Ply
• Requires Ply Based Modeling Techniques
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Composite Design Synthesis with Ply Based Modeling
0Deg Ply Shapes
90Deg Ply Shapes 45/-45Deg Ply Shapes
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Composite Size Optimization – How Many Plies?
• Stack Synthesized Ply Shapes
• Define Manufacturing Constraints
• Min/Max Ply Angle Percentages
• Balanced Laminates
• Define Optimization Targets
• Stress/Strain Targets
• Deformation/Buckling Targets
• Minimize Mass
• Perform Size Optimization to Determine Number of Plies Required to Meet Engineering 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)
90 Deg (2 Plys)
45 Deg (2 Plys)
-45 Deg (2 Plys)
0 Deg (2 Plys)
After Optimization
90 Deg (2 Plys)
45 Deg (2 Plys)
-45 Deg (2 Plys)
0 Deg (2 Plys)
Free-Size Results
Size Results
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Composite Shuffling – What is a Probable Stacking?
• Shuffling
• 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
• Constant Ply Thickness
After Optimization
Size Results Shuffle Results
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Unique Composite Design Methodology
• Design Synthesis (Concept Design) Technologies
• Isotropic Solid Topology
• Isotropic Shell Topology
• Isotropic Free-Size
• 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?
Complimentary Technologies
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• 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.
Baseline Model
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Stress Analysis
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Composite Optimization Stages
• Phase 1: Ply Shape optimization
• Phase 2: Ply Thickness optimization
• Phase 3: Ply Order optimization
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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
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Composite FE Model with 5 Stacks
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Base Laminate Stack 1
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Base Laminate Stack 2
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Base Laminate Stack 3
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Base Laminate Stack 4
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Base Laminate Stack 5
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Maximum Principal Strain Contour
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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
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Free Size Optimization for 0o Super Ply
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Free Size Optimization for +45o Super Ply
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Free Size Optimization for -45o Super Ply
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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
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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).
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Total Thickness of 0o Ply after Size Optimization
Stack 1 0o ply thickness
0.414 mm achieved by
four plies stacked
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Total Thickness of +45o Ply after Size Optimization
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Total Thickness of -45o Ply after Size Optimization
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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
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Stacking Sequence for Stack 1: 13 Plies
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Stacking Sequence for Stack 2: 16 Plies
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Stacking Sequence for Stack 3: 16 Plies
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Stacking Sequence for Stack 4: 4 Plies
PLY THK
41101 0.986
42101 0.931
43101 0.931
44101 0.974
maximum thickness in this stack is 3.822 mm
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Stacking Sequence for Stack 5: 4 Plies
PLY THK
51101 0.4164
52101 0.4085
53101 0.4085
54101 0.4164
maximum thickness in this stack is 1.649 mm
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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%/
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Conclusion
• A procedure for obtaining a composite fan blade from the given metallic
blade is presented.
• The steps in Composite ply optimization of the baseline composite are
presented. Five stacks are adopted here. The super plies and drop off plies
required are shown.
• A sizing optimization is performed for minimum weight. Manufacturing
constraints 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 account
manufacturing constraints. The stacking in all five stacks is shown.
• The weight savings of 27% was achieved for the structural load case
considered. The maximum strain is kept to be of the same order in the final
optimized vane as that in the metallic blade baseline, though the composite
can take much higher value.
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Thank You
Any Questions?