Finite Element Implementation of Biphasic-Fluid Structure Interactions in febio

Area of Science:

• Biomechanics and Multiphysics Modeling
• Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI)

Background:

• Hydrated biological tissues are often modeled as solid-fluid mixtures, known as biphasic materials, particularly in cartilage mechanics.
• Interactions between viscous fluids and porous tissues are crucial in physiological processes like synovial joint lubrication, cardiovascular, and respiratory mechanics.

Purpose of the Study:

• To implement a finite element solver in open-source software (febio) for dynamic interactions between viscous fluids and biphasic domains.
• To accommodate finite deformations and fluid exchange between domains, utilizing a novel hybrid biphasic formulation with a slightly compressible fluid.

Main Methods:

• Developed a biphasic-fluid-structure interaction (BFSI) solver within the febio framework.
• Verified the BFSI implementation against analytical and numerical benchmark problems, including novel solutions.
• Applied the solver to simulate 2D airflow through a face mask and 3D blood flow in a carotid artery.

Main Results:

• The BFSI solver demonstrated significant reduction in airflow dispersion through a simulated face mask.
• Accurate modeling of 3D blood flow in a bifurcated carotid artery with porous arterial walls was achieved.
• Mass conservation was verified across all fluid-permeable boundaries in the arterial flow simulation.

Conclusions:

• The successful formulation and implementation of the BFSI solver provide enhanced multiphysics modeling capabilities.
• This open-source tool offers accessible and advanced simulation for complex biomechanical and physiological systems.