Brake Industry and Brake Simulation This presentation discusses the business benefits to brake system design, thermal modeling, high fidelity CFD brake cooling and brake noise. Presentation given by Mike Hebbes, ANSYS Regional Technical Manager April 3, 2012

1. ANSYS Brake Simulation
Mike Hebbes
Regional Technical Manager
April 3, 2012
1 © 2011 ANSYS, Inc. May 9, 2012

2. The Brake Industry
Business Drivers Brake System Design Challenges
• Customer satisfaction • Virtual design of costs effective,
• Increase number of platforms quiet braking systems under ever
• Innovation increasing time pressure
• System Complexity
• Physics Complexity
• Number of Platforms
• Designers productivity
• In-sync models with production
• OEM and supply chain interaction
2 © 2011 ANSYS, Inc. May 9, 2012

3. ANSYS, Inc. Brake System Solutions
Solutions Business Benefits
 ANSYS brake application  50% faster in problem setup
experience  45% faster in project
 ANSYS system modeling, completion
Mechanical, CFD and  New product innovation
electromagnetics
 Multiphysics parametric
optimization with geometry
Interfaces to CAD
 Advanced capabilities to model
brake instability
3 © 2011 ANSYS, Inc. May 9, 2012

4. Brake System Design Considerations
System Modeling
Hydraulic
Control Structural
Electromagnetic Thermal stress
Dynamic loading Non-linear statics
Thermal Dynamics
Steady and NVH
Transient MBD
FEA and/or CFD Durability
Crash
Electromagnetic
Low and high frequency
Actuators, sensors
4 © 2011 ANSYS, Inc. May 9, 2012

5. Thermal Modeling
High Fidelity CFD Brake Cooling
Challenges
– Durability
– Predict local temperature
distributions and thermal loads
– Optimize brake venting
– Transient Drive Cycles
Advantages of ANSYS CAE
– MRF models, Conjugate heat transfer
– Easy and seamless transfer of CFD and
FEA data between applications
5 © 2011 ANSYS, Inc. May 9, 2012

6. Brake Instability Analysis
• Brake disk develop friction induced
oscillations which are heard as “brake
squeal”.
• Brake noise has been a challenging issue
for automotive industry.
• Brake Noise Categories
 Low frequency noise (100-1000 Hz) –
Groan and Moan noise
 Low frequency squeal (1000 – 7000 Hz) –
Coupling of out of plane modes of rotor
with bending modes of pads.
 High frequency squeal (8000-16000 Hz) –
Coupling of in plane modes of rotor with
Courtesy of:
bending modes of pads.
Automotive Company
6 © 2011 ANSYS, Inc. May 9, 2012

7. Early Approach
Standard FE Model provides M and K
Discrete 2 node (springs) elements are used to
provide Friction stiffness (MATRIX27)
Drawbacks
→Requires matching nodes at the sliding
interface
→Tedious and time consuming
→Rotor-pad interface is not treated
‘consistent’
“Complex Eigenvalue Analysis for Reducing Low Frequency Brake
→Impractical for parametric studies Squeal” by Shih-Wei Kung, K. Brent Dunlap and Robert S.
Ballinger,Delphi Automotive Systems
7 © 2011 ANSYS, Inc. May 9, 2012

8. ANSYS Workbench: Brake - System Model
Instability Procedure
• Provides for sliding • Complex Eigen solution
contact with friction • Animations: Complex
• Does not require Mode Shape
• Manual and/or Parametric Studies
matching meshes • Contact Status at Pads
Scripted Meshing • Supports higher order
elements
Single Simulation Environment
Mesh & Setup & Post
CAD
Connections solver Processing
• Bi-Directional CAD • Automated Contact • Flexibility to use Linear • Root locus plots
Connectivity Detection & Non-linear solver • Correlation of modes
• Automated Joint capabilities • Strain energy per
Sensitivity Studies and Counter Measures
Detection component per mode
• Parametric Studies
• Geometry variants
• Friction coefficient variations
• Material Properties (Anistotropic)
• RST MAC (Modal Assurance Criteria)
8 © 2011 ANSYS, Inc. May 9, 2012

9. Training/Documentation
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10. Production Intent CAD – CATIA V5
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11. Parametric Optimization
Pad Assembly Rotor
System Model
Caliper Knuckle
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12. Component Models
Pad (Friction Material)
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13. Goal Driven Optimization
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14. System Model
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15. Parametric Geometry Pre-Processing
Option 1: ANSYS DesignModeler
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16. Parametric and Persistent
ANSYS Geometry Interface for CATIA V5
Geometric
Parameter
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17. Parametric Geometry Pre-Processing
Option 2: ANSYS SpaceClaim Direct Modeler
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18. Parametric and Persistent
ANSYS Geometry Interface for CATIA V5
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19. Geometry Simplification
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20. Material Properties
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21. Contact Summary
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22. Contacts
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23. Contact - Bonded
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24. Contact - Frictional
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25. Joints
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26. Meshing
Integrated, Automated, Flexible
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27. Meshing
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28. Meshing
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29. Meshing
Automated Hex Meshing Examples
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30. Non Pre-Stressed, Complex Eigenvalue
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31. Full or Partial Pre-Stressed, Complex Eigenvalue
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32. Non Linear Static Structural
Boundary Conditions and Loads
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33. Contact Status Capture
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34. Restarts
34 © 2011 ANSYS, Inc. May 9, 2012

35. Non Pre-Stressed, Complex Eigenvalue
Post Processing: Damped Frequencies
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36. Non Pre-Stressed, Complex Eigenvalue
Post Processing: Stability
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37. Partial Pre-Stressed, Complex Eigenvalue
37 © 2011 ANSYS, Inc. May 9, 2012

38. Partial Pre-Stressed, Complex Eigenvalue
Post Processing: Stability
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39. Post Processing
Complex Eigenvalue
39 © 2011 ANSYS, Inc. May 9, 2012

40. Post Processing
Complex Eigenvalue Animations
40 © 2011 ANSYS, Inc. May 9, 2012