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 F04.30.06 May, 2007

Dimensional Correction 0.085mm 0.11mm

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

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

Location of Max Mean and Alternating Stress Mean Stress Alternating Stress

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

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

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