Fatigue Test System for Tubular Implants
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Solution Overview
Problem
Current fatigue test systems for tubular implant structures, such as stents, face challenges in applying well-defined and reproducible deformations, as they often rely on friction-fit connections that can lead to inconsistent loading and movement, making it difficult to compare results across different structures and potentially leading to over-optimistic assessments of their behavior under physiological conditions.
Innovation Solution
A fatigue test system that includes fixture assemblies to control the position of each end of the tubular implant structure, using form-fitting and/or force-fitting mechanisms to securely attach the structure to controllably moveable parts, ensuring well-defined and predetermined deformations are applied, thereby minimizing side effects and allowing for fair comparison across different designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If friction-fit connections are used to hold the tubular implant structure, then the structure can be easily positioned and tested, but the loading becomes inconsistent and movement is ill-defined, leading to over-optimistic assessment of behavior
Solution Approach 1:
The patent introduces fixture assemblies as intermediary components between the implant structure and the testing system. These fixtures provide controlled connection points that eliminate the friction-fit approach, ensuring well-defined loading conditions while maintaining ease of operation through standardized attachment mechanisms.
Solution Approach 2:
The invention changes the connection parameter from friction-based (unreliable) to mechanically controlled (reproducible). By using fixture assemblies with defined geometric and mechanical properties, the system transforms the interaction mode to achieve consistent, reproducible deformation across different implant structures.
2Adaptability or versatility
If the implant structure is allowed to move freely during testing, then it can simulate physiological conditions, but the deformation becomes ill-defined and difficult to control, making comparison across different structures difficult
Solution Approach 1:
The testing system is segmented into controllable parts (fixture assemblies) that can independently position and control each end of the implant structure. This segmentation allows precise control of deformation while maintaining the ability to simulate physiological movement patterns through coordinated movement of the fixture components.
Solution Approach 2:
The fixture assemblies are designed to be dynamically controllable, allowing the system to transition between static positioning and dynamic movement simulation. This enables precise control of deformation parameters while still accommodating physiological movement patterns through programmed actuator sequences.
3Adaptability or versatility
If different designs are subjected to different positioning during testing, then each structure can be tested in its optimal configuration, but the results cannot be fairly compared across different designs
Solution Approach 1:
The fixture assemblies are designed as universal components that can accommodate different implant structure designs while maintaining consistent loading and positioning protocols. This multi-functionality allows each design to be tested in its optimal configuration while ensuring that all structures undergo comparable, standardized deformation conditions for fair comparison.
Data Source
AI summary
A fatigue test system for repetitively deforming a substantially tubular implant structure which is within a radial range and within an axial range expandable and contractable and which has at least a first and a second end, wherein the system comprises at least a first and second part which are controllably moveable relative to each other, and a first and a second fixture assembly for fixing the first end to the first part and the second end to the second part, so that the system controls in use the position of each of the first and second end of the tubular implant structure.