10 Oct Single device level Hierarchical VVUQ Strategy

Single Device Component Level in Hierarchical VVUQ Strategy for Biodegradable Pulmonary Heart Valve Development

Welcome to the third installment in our blog series on the Hierarchical VVUQ Strategy for the development of biodegradable pulmonary heart valves as part of the EU-funded SimInSitu project. In this post, we delve into the Single Device Component Level, where we focus on the modeling, verification, and validation of the individual components of the pulmonary valve (PV).

Read the first blog post: Hierarchical VVUQ Strategy
Read the second blog post: Material level Hierarchical VVUQ Strategy

Device Component Modeling

To accurately represent the PV device, we modeled it in three relevant sizes: 16mm, 18mm, and 20mm. Both key components, the conduit and the leaflets, were modeled fully parametrically to ensure the necessary degree of parameter flexibility. Key aspects of this modeling approach included:
– Leaflet Positioning and Alignment: The positioning and alignment of the individual leaflets within the conduit were modeled using various positioning parameters.
– Trim Position and Angles: The positioning and alignment of the individual leaflets within the conduit were modeled using various positioning parameters.
– Thickness Distribution and Material Direction: The positioning and alignment of the individual leaflets within the conduit were modeled using various positioning parameters.
– Sinus Shape of the Conduit: This was introduced into the model through a virtual manufacturing step where the individual leaflets imprint the final shape from the inside.
All components were meshed with three-dimensional continuum elements, ensuring a detailed and accurate representation, as shown in the picture below.

Verification

Verification activities at the component level covered all relevant credibility factors, including:
– Code Verification: Ensuring the correctness of the implemented code.
– Discretization Error: Addressing both spatial and temporal discretization errors.
– Solver Error: Ensuring the accuracy of the numerical solver.
The primary model outputs were stress and strain development. Verification results demonstrated a relative error around or smaller than 1%, indicating high model accuracy.

Validation and Uncertainty Quantification

Due to the intrinsic manufacturing process of the PV, conducting meaningful experimental tests on the individual components was not feasible. Therefore, validation and uncertainty quantification activities were performed at the assembly level with the entire PV device. This approach ensured that all component interactions and overall device behavior were accurately captured and validated.

Conclusion

The Single Device Component Level is a critical step in our hierarchical VVUQ strategy, providing detailed modeling and rigorous verification of each component. In our next post, we will explore the Complete Device Level, where we focus on the assembly of the entire device and the extensive testing involved to ensure its functionality and reliability. Stay tuned for more insights into our journey to develop a credible, patient-specific in-silico FEM model for biodegradable pulmonary heart valves.