Concept Optimal Design of Composite Fan Blades

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Presented by

Dr. Robert Yancey

[email protected]

Concept Optimal Design of Composite Fan Blades

J. S. Rao, S. Kiran and B. Bombale

mailto:[email protected]

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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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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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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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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?