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28.04.2006
Analysis and Optimization of a Hybrid Fan BladePermas Users´ Conference
27.04.06 – 28.04.06 Strassbourg
DLR German Aerospace Center, StuttgartInstitute of Structures and Design
J. Ehrmanntraut, F. Kocian, V. Plevnik, T. Schmidt, D. Schwinn
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 228.04.2006
Topics
• Single spool LPC (Low Pressure Compressor) based on EJ200 turbo jet engine
• Mass reduction in first stage by implementation of CFRP (Carbon Fibre Reinforced Plastics)
• FEM modelling and structural analysis of a hybrid blade
• Modification of dynamic response of a titanium blade by topologyoptimization
• Introduction of a new monolithic stacked rotor
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 328.04.2006
LPC Low Pressure Compressor (EJ200 Turbo Jet Engine)
Titanium BLISK
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 428.04.2006
Hybrid Blade
• Titanium in the front region due to erosion and foreign object damage
• CFRP (Carbon Fibre Reinforced Plastics) in the rear region for mass reduction (CF-PEEK Prepreg)
• ± 45° and 0° lay-up optimized for torsion and bending stiffness
• Consolidation of CFRP and joining to the titanium in one process step
Target: mass reduction
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 528.04.2006
Hybrid BladeAsymmetric Double Lap Shear Joint
suction side view
CFRP part
titanium part
joining area
pressure side view
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 628.04.2006
FEM Model:• Blade:
- 2746 HEXE8, 287 QUAD4, 782 SHELL4 elements- 25 properties
• Disc: - 6334 HEXE8 elements
• Material : - Ti64, CF-PEEK (based on unidirectional thermoplastic
prepreg)• Loading:
- inertial rotation, aerodynamic pressure, temperature load• Cyclic symmetry by MPC JOIN• Blade/disc joint by MPC ISURFACE
Hybrid Blisk: Pressure Side ViewAA
Suppressed DOF 2,3 (cyl. coor. system)
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 728.04.2006
Approach for QUAD4 (Ti) - SHELL4 (CFRP) Coupling in Double Lap Shear Joint Region
• Different deformation mechanisms of isotropic and orthotropic materials by transverse loading
• Dominance of bending deformation in titanium and shear deformation in CFRP leads to different rotation at element nodes
• Incorrect increase of stiffness by coupling of all DOFs=> MPC RIGID only DOFs 1,2,3
• Separation of element reference and laminate middle surface in SHELL4 elementsby
• Using forces on dependent nodesfor further evaluation of joining area
Titanium
CFRP
Titanium
CFRP
1=ξ
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 828.04.2006
Hybrid Blade: Meshing of Double Lap Shear Joint Region
1ξ =
HEXE8
QUAD4
SHELL4
outer ply (first ply in stacking sequence)
MPC RIGID (1,2,3)
MPC ILIN2 (1,2,3) MPC VST (1,2,3,4,5,6)
MPC RIGID (1,2,3)
Section AA (scaled)
pressure side
suction side
1ξ =
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 928.04.2006
Stress Distribution in Double Lap Shear Joint Region
A1
A3A2
A4
force on dependent node
F
normal vector n1
F1j out of planeF1j
F1j in plane
1
4
11
1
1
4
11
1
11
4
1
)()(;
)()(
;
A
planeinFshear
A
planeofoutFpeel
AAFFAA
jj
jj
ji
i
∑∑
∑
==
≤
=
==
⋅==
τσ
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1028.04.2006
1. HEXE8 elements in the front titanium region2. QUAD4 elements for titanium in joining area3. SHELL4 elements for CFRP4. HEXE8 - QUAD4 transition by MPC VST and MPC ILIN25. QUAD4 - SHELL4 coupling in joining area by MPC RIGID (1,2,3)6. Evaluation of forces on dependent nodes for stress calculation in the joining area 7. Conversion of forces on dependent nodes to element forces8. Splitting of element forces in “in plane” and “out of plane”9. Calculation of peeling and shear stresses
Summary for FEM Modelling of Hybrid Joints
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1128.04.2006
• nonlinear analysis• inertial rotation, • aerodynamic pressure• temperature load
“continuous” v. Mises stress distribution in the volume/shell region
Hybrid Blisk: V. Mises Stress Distribution in Titanium Part [MPa]
suction side pressure side
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1228.04.2006
nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load
pressure side suction side
Peeling Stress Distribution in Double Lap Shear Joint Region
4.18 [MPa] 2.63 [MPa]
-1.79 -1.77
maximum 4.18 MPa
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1328.04.2006
Shear Stress Distribution in Double Lap Shear Joint Region
pressure side suction side
nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load
0.48 0.44
23.0 [MPa] 14.2 [MPa]
maximum 23.0 MPa
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1428.04.2006
maximum approx. 80%
Utilisation Factor in CFRP Region Tsai-Wu Criterion
pressure side suction side
nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load
1.0 1.0
0.0 0.0
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1528.04.2006
Hybrid Blade:Campbell-Diagram
• Vibration analysis• Consideration of nonlinear effects caused
by inertial rotation, aerodynamic pressure and temperature load
1C1T
1F 2F
deformation magnitude
Campbell Diagram BLISK17 hybrid
60% Nn 100% Nn43% Nn
EO 1
EO 2
EO 3
EO 4
EO 5
EO 53
1F
2F
1T
1C
2C
0
500
1000
1500
2000
0 50 100 150 200
Shaft speed rot/s
Freq
uenc
y H
z
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1628.04.2006
Topics
Single spool LPC (Low Pressure Compressor) based on EJ200 turbo jet engine
Mass reduction in first stage by implementation of CFRP (Carbon Fibre Reinforced Plastics)
FEM modelling and structural analysis of a hybrid blade
• Modification of dynamic response of a titanium blade by topologyoptimization
• Introduction of a new monolithic stacked rotor
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1728.04.2006
FEM Model:• Blade:
- 15008 elements (HEXE8)• Disk:
- 21528 elements (HEXE8)• Material : Ti64• Loading:
- inertial rotation, aerodynamic pressure, temperature load
• Cyclic symmetry by MPC JOIN• Blade/disc joint by MPC ISURFACE
Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization
Suppressed DOF 2,3 (cyl. coor. system)
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1828.04.2006
Campbell Diagram C03i4_h23_ti_cold
EO 1
EO 2
EO 3
EO 4
EO 5
70% Nn ADP 110% NnEO 53
1F
2F
1T
0
500
1000
1500
2000
2500
0 50 100 150 200 250Shaft speed rot/s
Freq
uenc
y Hz
• Vibration analysis• Consideration of nonlinear effects
caused by inertial rotation, aerodynamic pressure and temperature load
• Interaction between second flexural and first torsion mode in the whole operating range (risk of twist bend coupling)
Titanium Blade:Campbell Diagram
2F 1T
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 1928.04.2006
Modification of Dynamic Eigenfrequenciesof Titanium Blade using Topology Optimization
• Design elements (DHEXE8) with variable filling ratio (density, stiffness) in the inner part of titanium blade
• Definition of design objective function by $DCFUNCTION: [ f(1T) – f(2F) ] => AbsMax
• Combination of vibration analysis with TOPO• Analysis of results and modification of the inner part of
the titanium blade by deleting FEM-elements with negligible filling ratio
• Verification of topology optimization results by a vibration analysis
design region
outer blade elements not
shown
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 2028.04.2006
filling ratio f after 30 iterations,convergence achieved
deleting of FEM elements with negligible filling ration in the top blade region
Modification of Dynamic Eigenfrequenciesof Titanium Blade using Topology Optimization
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 2128.04.2006
Separation of second flexural and first torsion mode in the whole operating range !
Campbell Diagram C03i4_h23_ti_topo_1
EO 1
EO 2
EO 3
EO 4
EO 5
70% Nn ADP 110% NnEO 53
1F
2F
1T
0
500
1000
1500
2000
2500
0 50 100 150 200 250Shaft speed rot/s
Freq
uenc
y Hz
Optimized Titanium Blade:Campbell Diagram
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 2228.04.2006
Realization Concept of Optimized Rotor:Monolithic Stacked Rotor
• Repair of the rotor by replacing any planar discs
• Joining of the planar discs by brazing or welding
• Combination of different materials to hybrid structures
• Implementation of damping mechanisms
• Several planar discs building the whole rotor• Each planar disc is sustainable of its own• Accessibility allows any cavities in blades and
discs
Computer Supported Component Design Permas Users´ Conference 2006 J. Ehrmanntraut foil 2328.04.2006
Conclusion:
• Simple approach for modelling of hybrid joints leads to good results• Approach for QUAD4 (Ti) - SHELL4 (CFRP) coupling applicable to
similar joining structures • Successful verification of approach for QUAD4 (Ti) - SHELL4 (CFRP)
coupling by simple test specimens• Dynamic eigenfrequencies separation of titanium blade achieved by
topology optimization
28.04.2006
Thank you for your attention
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