Finite Element Analysis Stent FEA: Measured parameters
- Global behavior and mechanical properties (stress, strain, etc) of device during various loadings (crimping, expansion, etc)
- Stent Recoil behavior
- Stent Foreshortening behavior
- Stent expansion behavior
- Stent compression behavior
- Stent fatigue assessment
- Stent deployment
- Stent design performance capabilities
Finite Element Analysis Stent FEA: Scope
- PTA, PTCA, coronary and peripheral stent
- Any cardiovascular implants
- Any medical device implants
Finite Element Analysis Stent FEA: Applicable standards
- Accelerate Fatigue Testing: Minimum & Maximum physiological target strain, preliminary assessment of fatigue resistance, worst case stress and strain level for device size identification.
- Accelerated stent fatigue testing
Stent Finite Element Analysis Stent FEA: Test method description
FEA try to depict the real life cycle of the stents in order to anticipate real stresses and strains encountered in the stents. Therefore, we simulate the different steps for each stent:
- The crimping of the stent from its initial diameter to crimped outer diameter: This step uses a modeled cylindrical structure (with a larger diameter than the stent) with radial wall displacement. The cylinder induces stent diameter reduction until the diameter of crimping was reached.
- The recoil after crimping: the cylinder used for crimping is removed to study the recoil of the stent and to remove stresses due to crimping.
- The expansion of the stent from the crimped diameter to its nominal diameter (deployed inner diameter). We use a modeled balloon located inside the stent. The balloon is deployed and induces a radial expansion of the stent until the stent reaches its inner nominal diameter.
- The recoil after expansion: The balloon is removed to study the recoil of the stent without loading.
The fatigue investigation: The stent can undergo a simulated physiological pulsatile pressure load. To perform this simulation we will apply different pressures on the outer surface of the stent to study its radial strength. We will analyze stresses and strains in each pressure case and use a Goodman diagram to estimate if the structure will resist to the pulsation.