Functional and Structural Analysis of Auxetic Metamaterial Stent Designs for Thoracic Aortic Aneurysms Using Finite...

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Computational Mechanics

Background:

• Thoracic aortic aneurysms necessitate large stent grafts, but current designs struggle with wall apposition and anatomical adaptability.
• Auxetic metamaterials with negative Poisson's ratio offer potential for improved stent applications, yet optimal designs require further investigation.

Purpose of the Study:

• To compare the mechanical performance of different auxetic stent designs.
• To identify the most suitable auxetic configuration for thoracic aortic stent grafts.

Main Methods:

• Investigated four auxetic designs (rotating square, re-entrant, peanut, rotating triangle) using magnesium alloy specimens.
• Conducted quasi-static experimental tests and finite element simulations under clinically relevant loading conditions (compression, expansion).
• Evaluated deployment behavior, including recoiling, stiffness, and deformation.

Main Results:

• Auxetic geometry significantly influences stent recoil, stiffness, and deformation.
• The rotating triangle (RT) design exhibited substantially lower radial stiffness (84%-97% reduction) and moderate foreshortening (7.10%).
• RT design showed a balanced mechanical response, suggesting potential for controlled deployment and stable apposition despite higher recoil.

Conclusions:

• The rotating triangle auxetic stent design demonstrates superior mechanical properties for thoracic aortic applications.
• This design offers improved adaptability and wall apposition compared to other auxetic configurations.
• Further research into auxetic stent designs can advance treatment for thoracic aortic aneurysms.