Computational Modeling of Diffusion-Based Delamination for Active Implantable Medical Devices

Area of Science:

• Bioengineering
• Materials Science
• Mechanical Engineering

Background:

• Delamination at material interfaces is a critical failure mode in active implantable medical devices (AIMDs).
• Body fluid infiltration into polymer substrates and along metal-polymer interfaces complicates modeling of AIMDs, such as cochlear implants (CIs).
• Existing digital twin models lack the complexity to address biofluid infiltration in AIMDs.

Purpose of the Study:

• To develop and validate a mathematical model for delamination and body fluid infiltration in AIMDs, specifically CIs.
• To enhance understanding of failure mechanisms in silicone rubber and metal-based AIMDs.
• To provide a framework for digital twin development in bioengineering.

Main Methods:

• Implementation of a mathematical model using COMSOL Multiphysics®.
• Incorporation of volume diffusion and interface diffusion (delamination) models.
• Validation against experimental data from a newly developed test for AIMDs/CIs.

Main Results:

• The model successfully derived diffusion coefficients from experimental data.
• A good qualitative and functional match was observed between experimental and modeling results.
• The interface diffusion model accurately approximated previous experimental findings.

Conclusions:

• The developed mathematical model provides a better understanding of AIMD failure mechanisms.
• The model's validation against real-life data supports its utility for predicting device performance.
• This work advances the development of complex digital twins for bioengineering applications.