1. Fatigue to Failure: FEA Predictions of Limit Conditions for Axial Fatigue Loading of Generic Coronary Stent Designs Part 2: Geometry 1 with EP correction
Prepared for ASTM F May, 2007

2. Dimensional Correction
0.085mm
0.11mm

3. Expansion Analysis Stress at max expansion Stress after recoil
Plastic strain due to expansion

4. Ideal ID Expansion [mm]
Expanded Diameter
Expansion
Recoil
Ideal ID Expansion [mm]
2.926
Maximum OD [mm]
3.34
3.19
Minimum ID [mm]
2.9
2.75
Expansion
Minimum ID
Recoil
Maximum OD

5. Location of Max Mean and Alternating Stress
Mean Stress
Alternating Stress

6. Effect of Residual Stress
Effective stress during extension
with residual expansion stress
Effective stress during extension
without residual expansion stress
Case
Extension
Max Stress
Comments
Residual Stress
±0.33%
364MPa
-Large tensile and compressive stresses in the middle of struts and bridges
-Yield stress increased due to load history
No Residual Stress
110MPa
-Uniform load path with unaltered yield stress

7. Fatigue Scenario Studies
Case
Stress State
Strain State
Fatigue Condition
Mean Stress
Alternating Stress
Expanded
Residual Stress
~300MPa
Cold Work
~4.8%
±0.33%
243 MPa
121 MPa
±0.27%
98 MPa
(annealed)
No Residual Stress
No Cold Work
0 MPa
110MPa

9. Fatigue Analysis ±.70 % is roughly Here ±.50 % is roughly Here
±.33 % is Here
±.33 % without residual stress is Here