Analysis and Optimization of a Hybrid Fan Blade

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1 Analysis and Optimization of a Hybrid Fan Blade Permas Users Conference Strassbourg DLR German Aerospace Center, Stuttgart Institute of Structures and Design J. Ehrmanntraut, F. Kocian, V. Plevnik, T. Schmidt, D. Schwinn

2 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 topology optimization Introduction of a new monolithic stacked rotor Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 2

3 LPC Low Pressure Compressor (EJ200 Turbo Jet Engine) Titanium BLISK Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 3

4 Titanium in the front region due to erosion and foreign object damage Hybrid Blade 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 4

5 pressure side view Hybrid Blade Asymmetric Double Lap Shear Joint CFRP part suction side view joining area titanium part Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 5

AA Hybrid Blisk: Pressure Side View FEM Model: Blade: - 2746 HEXE8, 287 QUAD4, 782 SHELL4 elements - 25 properties Disc: - 6334 HEXE8 elements Material : - Ti64, CF-PEEK (based on unidirectional

6 AA Hybrid Blisk: Pressure Side View FEM Model: Blade: HEXE8, 287 QUAD4, 782 SHELL4 elements - 25 properties Disc: 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 Suppressed DOF 2,3 (cyl. coor. system) Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 6

7 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 elements by ξ =1 Using forces on dependent nodes Titanium Titanium for further evaluation of joining area CFRP CFRP Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 7

8 Hybrid Blade: Meshing of Double Lap Shear Joint Region Section AA (scaled) HEXE8 MPC RIGID (1,2,3) ξ = 1 suction side outer ply (first ply in stacking sequence) ξ = 1 QUAD4 MPC ILIN2 (1,2,3) MPC VST (1,2,3,4,5,6) SHELL4 pressure side MPC RIGID (1,2,3) Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 8

1 j A1 = F A ( out A of plane) 1 ; τ ( shear) 1 = 4 j= 1 F 1 j ( in A 1 F 1j in plane

9 Stress Distribution in Double Lap Shear Joint Region force on dependent node F A 1 A3 A 2 A 4 normal vector n 1 F 1j F 1j out of plane A = 1 4 i= 1 A σ ( peel) i = ; 4 j= 1 F F 1 j 1 j A1 = F A ( out A of plane) 1 ; τ ( shear) 1 = 4 j= 1 F 1 j ( in A 1 F 1j in plane plane) Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 9

10 Summary for FEM Modelling of Hybrid Joints 1. HEXE8 elements in the front titanium region 2. QUAD4 elements for titanium in joining area 3. SHELL4 elements for CFRP 4. HEXE8 - QUAD4 transition by MPC VST and MPC ILIN2 5. 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 forces 8. Splitting of element forces in in plane and out of plane 9. Calculation of peeling and shear stresses Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 10

rotation, aerodynamic pressure temperature load continuous v.

11 Hybrid Blisk: V. Mises Stress Distribution in Titanium Part [MPa] nonlinear analysis inertial rotation, aerodynamic pressure temperature load continuous v. Mises stress distribution in the volume/shell region suction side pressure side Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 11

12 Peeling Stress Distribution in Double Lap Shear Joint Region nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load 4.18 [MPa] 2.63 [MPa] maximum 4.18 MPa pressure side suction side Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 12

Shear Stress Distribution in Double Lap Shear Joint Region nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load 23.

13 Shear Stress Distribution in Double Lap Shear Joint Region nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load 23.0 [MPa] 14.2 [MPa] maximum 23.0 MPa pressure side suction side Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 13

Utilisation Factor in CFRP Region Tsai-Wu Criterion nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load 1.0 1.

14 Utilisation Factor in CFRP Region Tsai-Wu Criterion nonlinear analysis, inertial rotation, aerodynamic pressure and temperature load maximum approx. 80% pressure side 0.0 suction side 0.0 Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 14

15 Hybrid Blade: Campbell-Diagram EO 53 Campbell Diagram BLISK17 hybrid Vibration analysis Consideration of nonlinear effects caused by inertial rotation, aerodynamic pressure and temperature load C 1C 1F 2F Frequency Hz T EO 5 EO 4 2F EO 3 1T 1C 500 EO 2 1F EO 1 deformation magnitude 0 43% Nn 60% Nn 100% Nn Shaft speed rot/s Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 15

16 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 topology optimization Introduction of a new monolithic stacked rotor Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 16

Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization FEM Model: Blade: Disk: - 15008 elements (HEXE8) - 21528 elements (HEXE8) Material : Ti64 Loading: - inertial

17 Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization FEM Model: Blade: Disk: elements (HEXE8) elements (HEXE8) Material : Ti64 Loading: - inertial rotation, aerodynamic pressure, temperature load Cyclic symmetry by MPC JOIN Blade/disc joint by MPC ISURFACE Suppressed DOF 2,3 (cyl. coor. system) Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 17

Titanium Blade: Campbell Diagram Vibration analysis Consideration of nonlinear effects caused by inertial rotation, aerodynamic pressure and temperature load Interaction between second flexural and

18 Titanium Blade: Campbell Diagram 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) Frequency Hz Campbell Diagram C03i4_h23_ti_cold EO 53 70% Nn ADP 110% Nn EO T EO 4 2F EO EO 2 1F EO 1 2F 1T Shaft speed rot/s Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 18

Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization Design elements (DHEXE8) with variable filling ratio (density, stiffness) in

Analysis of results and modification of the inner part of the titanium blade by deleting FEM-elements with negligible filling ratio Verification of topology

19 Modification of Dynamic Eigenfrequencies of 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 outer blade elements not shown design region Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 19

Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization filling ratio f after 30 iterations, convergence achieved deleting of

20 Modification of Dynamic Eigenfrequencies of Titanium Blade using Topology Optimization filling ratio f after 30 iterations, convergence achieved deleting of FEM elements with negligible filling ration in the top blade region Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 20

21 Optimized Titanium Blade: Campbell Diagram 2500 Campbell Diagram C03i4_h23_ti_topo_1 EO 53 70% Nn ADP 110% Nn Separation of second flexural and first torsion mode in the whole operating range! Frequency Hz EO T EO 4 2F EO F EO 2 EO Shaft speed rot/s Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 21

planar discs Joining of the planar discs by brazing or welding Combination of different materials to hybrid structures

22 Realization Concept of Optimized Rotor: Monolithic Stacked Rotor Several planar discs building the whole rotor Each planar disc is sustainable of its own Accessibility allows any cavities in blades and discs 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 Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 22

23 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 Computer Supported Component Design Permas Users Conference 2006 J. Ehrmanntraut foil 23

24 Thank you for your attention

Computational Analysis for Composites

Computational Analysis for Composites Professor Johann Sienz and Dr. Tony Murmu Swansea University July, 011 The topics covered include: OUTLINE Overview of composites and their applications Micromechanics