Biphasic finite element modeling of hydrated soft tissue contact using an augmented Lagrangian method

Area of Science:

• Biomechanics
• Computational Mechanics
• Biomedical Engineering

Background:

• Understanding biphasic soft tissue contact is crucial for analyzing human diarthrodial joint biomechanics.
• Previous biphasic-biphasic contact models were limited to idealized geometries.
• Generalizable contact analysis for complex joint geometries remains a challenge.

Purpose of the Study:

• To develop a finite element formulation for biphasic soft tissue contact applicable to general geometries.
• To implement and verify this formulation for accurate biomechanical analysis.
• To provide a robust computational tool for studying joint mechanics.

Main Methods:

• Developed a finite element formulation for biphasic tissue contact.
• Utilized the augmented Lagrangian method to ensure continuity of contact traction and fluid pressure.
• Implemented the formulation in COMSOL Multiphysics and validated with 2D axisymmetric problems.

Main Results:

• Verified the accuracy of the finite element implementation through various indentation and cartilage contact simulations.
• Demonstrated the robustness of the biphasic contact formulation.
• Showcased the capability to handle physiologically relevant problems.

Conclusions:

• The developed finite element formulation provides a robust and accurate method for analyzing biphasic soft tissue contact in general geometries.
• This advancement enables more realistic biomechanical simulations of human diarthrodial joints.
• The implementation is suitable for investigating complex, physiologically relevant joint behaviors.