Thesis
Fabric modelling and effects of fluid flow disruption in endovascular devices
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17481
- Person Identifier (Local)
- 202190936
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Abdominal Aortic Aneurysms (AAA) present a significant health risk due to the risk of rupture, leading to life-changing and potentially fatal complications. Endovascular aneurysm repair (EVAR) using stent grafts has become the preferred treatment method due to its minimally invasive nature. However, long-term complications including graft migration, endoleaks and thrombosis continue to occur and often require reintervention. This thesis investigates the mechanical behaviour of the woven biofabric used in stent grafts and its influence on the overall performance of endovascular devices, with a particular focus on fabric deformation, device stiffness, and fluid flow disruption. A comprehensive experimental characterisation of the woven bio-fabric was conducted, including testing in the tensile, shear, and bending directions to determine the fabrics mechanical properties under loaded conditions, creating a solid framework for future fabric studies. Finite element models (FEA) were developed through bespoke material models, previously not utilised within the field, and validated to simulate the interaction between the fabric and the nitinol ring scaffold, capturing the complex deformation of the stent graft. Experimental studies in representative stent graft devices assessed axial and bending stiffness through novel methods which open up new avenues in stent graft design and reveal the influence of the fabric properties on the flexibility and conformance to the arterial wall. To further evaluate the impact of fabric deformation on haemodynamics, computational fluid dynamics (CFD) simulations were performed, integrating patient-derived geometric variations and in vivo pressure conditions. The study analysed key haemodynamic parameters such as wall shear stress (WSS), recirculation zones, low flow regions, and other relevant factors linked to the formation of thrombus. The findings highlighted the role of fabric deformation in altering local flow conditions. The research outcomes contribute to the advancement of stent graft design by providing a detailed understanding of the mechanical and fluid dynamics within endovascular devices. The developed modelling framework improves the predictive capabilities for device performance, helping in the development of the next generation of stent grafts with improved hemodynamic efficiency. These insights have direct implications for clinical practice, offering strategies to improve long-term patient outcomes and following EVAR procedures and reduce postoperative complications.
- Advisor / supervisor
- Dempster, William
- Nash, David
- Resource Type
- Note
- The stress-strain data in chapter 3 has been redacted at the request of the supplier.
- DOI
- Funder
- Embargo Note
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File | 2025-11-11 | Private |