Prestressing in finite deformation abdominal aortic aneurysm simulation

Area of Science:

• Biomechanics
• Computational mechanics
• Medical imaging analysis

Background:

• Patient-specific geometries for abdominal aortic aneurysm (AAA) simulations are often derived from medical imaging (e.g., CT scans).
• These reconstructed geometries reflect in vivo conditions but are typically treated as stress-free in simulations.
• This simplification can lead to inaccuracies in finite strain biomechanical modeling.

Purpose of the Study:

• To develop and compare two methods for introducing a physically meaningful stress/strain state into patient-specific AAA geometries.
• To demonstrate the necessity of prestressing techniques for accurate finite strain simulations of AAA.
• To evaluate the applicability and accuracy of these prestressing methods on 3D AAA models.

Main Methods:

• An inverse design analysis approach to compute a stress-free reference configuration.
• A modified updated Lagrangian formulation for incorporating prestress.
• Formulation and comparison of both methods using 3D patient-specific AAA models in the finite strain regime.

Main Results:

• Both presented prestressing techniques can introduce a physically meaningful stress/strain state to AAA geometries.
• The study demonstrates the critical need for prestressing in accurate finite strain simulations of AAA.
• Comparative evaluation of the two methods' applicability and accuracy on complex 3D AAA structures was performed.

Conclusions:

• Accurate finite strain simulations of abdominal aortic aneurysms necessitate the inclusion of prestress.
• The developed inverse design and modified updated Lagrangian methods offer viable approaches for modeling prestressed AAA geometries.
• These prestressing techniques enhance the fidelity of patient-specific biomechanical simulations for AAA.