Self-Expandable Shape Memory Alloy Stent with Interlocking Rhombic Weave
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Solution Overview
Problem
Conventional self-extendable shape memory alloy stents face challenges in maintaining the original shape of winding blood vessels and preventing longitudinal contraction or extension, leading to unwanted deformation and reduced workability during installation.
Innovation Solution
A self-expandable stent design featuring a primary and secondary stent member woven with super-elastic shape memory alloy wires, using a base jig with specific diagonal lengths and zigzag patterns to create interlocking rhombic spaces, which allows the stent to maintain shape and prevent longitudinal length variation while maximizing circumferential elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a self-extendable stent with diametrically outwardly acting elastic force is used to expand the blood vessel, then the stenotic passage is expanded effectively, but the blood vessel shape is straightened without maintaining the original winding condition, causing length increase and passage reduction at the ends
Solution Approach 1:
The stent employs a dynamic weaving structure with intersecting wires that can adapt their configuration. The wires are arranged to form a flexible mesh that can dynamically adjust to match the blood vessel's natural curvature, whether straight or winding, allowing the stent to expand effectively while conforming to and maintaining the original vessel shape without causing straightening or length changes
2Adaptability or versatility
If the stent is designed with high circumferential elasticity to expand the blood vessel, then the stenotic passage expansion is maximized, but longitudinal compression or extension occurs during installation, causing length variation and reduced workability
Solution Approach 1:
The stent structure exhibits different mechanical properties in different directions: the wire intersections and weaving pattern are designed to provide high circumferential elasticity for effective blood vessel expansion, while the longitudinal wire arrangement and intersection geometry simultaneously provide longitudinal rigidity to prevent compression or extension during installation, thus maximizing adaptability without compromising ease of operation
3Volume of moving object
If the stent is compressed heavily to reduce volume for insertion through guide tube, then the stent can be inserted into target stenotic portion, but the rhombic spaces are reduced and the stent structure is deformed
Solution Approach 1:
The stent utilizes a dynamic reversible deformation mechanism where the wire mesh structure can be compressed to reduce volume for insertion through the guide tube, and then spontaneously returns to its original expanded configuration with restored rhombic spaces upon deployment, maintaining structural integrity throughout the insertion and expansion process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stent effectively expands and maintains the shape of stenotic passages, whether straight or winding, minimizing deformation and ensuring efficient installation by preventing longitudinal contraction or extension, while maximizing circumferential elasticity.
Implementation Method 1
a self-extendable stent that has a hollow cylindrical body comprised of a super-elastic shape memory alloy wire
Implementation Method 2
self-extendable shape memory alloy stent
Data Source
AI summary
A self-expandable shape memory alloy stent includes first and second wires made of super-elastic shape memory alloy. The first wire extends downwardly from the top to the bottom of the stent without interlocking with itself but extends upwardly from the bottom to the top of the stent while interlocking with itself to leave a multiplicity of rhombic spaces. Similarly, the second wire extends downwardly from the top to the bottom of the stent without interlocking with itself but extends upwardly from the bottom to the top of the stent while interlocking with itself, in such a manner as to divide the rhombic spaces formed by the first wire into four small rhombic spaces. The first wire and the second wire are woven with each other in such a manner that the second wire passes alternately below and above the first wire at intersection points.