1. Proposal Presentation:
Multiaxial Fatigue Analysis of Composite Tension-Torsion Straps for Rotor Systems
Ryan T. Casey

2. Tension-Torsion Strap
McDonnell Douglas MD-500E Rotor Head

3. Common Rotor System Configuration for T-T Strap
Tension-Torsion Strap
Flap Hinge
Lead/Lag Hinge
Pitch Housing
Blade Attachment

4. Loading Conditions of T-T Strap
CF Load
Torsional Twist due to Pitch Input
Small Flatwise Bending due to Pitch Housing Deflection

5. Methodology Classical Laminate Theory Develop FEA model
Material Properties (E, G, etc…)
Develop FEA model
Determine Notch Factors
Develop Stress Spectrum
Multiaxial Fatigue Failure Theories:
Max Principal Strain, Von Mises, Max Shear Strain, Lohr-Ellison, Kandil-Brown-Miller

6. Expected Results Fatigue Life Range Prediction for Composite T-T Strap
FEA Models (ANSYS Workbench)
Equivalent Material Properties from Laminate Theory
Notch Factors

7. Project Task Milestones
Due Date
Research in Classical Laminate Theory &
Classical Laminate Theory
February 12, 2010
Determine Design Parameters/Requirements
Common Stress Spectrum Creation
February 19, 2010
Complete FEA of Metal Strap Configuration
March 5, 2010
Composite Design concurrent w/ FEM & Fatigue Analysis
Finalize Composite Strap Design
March 19, 2010
Complete FEM & Fatigue Life Analysis
March 26, 2010

8. Questions
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