Vision-Based Shape Memory Alloy Test Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing test apparatuses for determining transformation temperatures of shape memory metal alloys, such as nickel titanium alloys, face issues with accuracy due to contact measurement methods, hazardous and costly cooling agents, and inadequate temperature control, while also being limited to testing a single specimen at a time.
Innovation Solution
A non-contact test apparatus and method using a vision-based optical system with a camera to track shape changes of multiple specimens submerged in a temperature-controlled bath, allowing for simultaneous testing and accurate determination of transformation temperatures without physical contact, utilizing a two-stage chiller unit for precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact transducer (LVDT) is used to measure specimen displacement, then the measurement can be obtained, but the accuracy of test data is adversely affected
Solution Approach 1:
The patent replaces the mechanical contact transducer (LVDT) with an optical measurement system that uses a camera and image analysis to track specimen displacement. This substitution eliminates mechanical contact between the measurement device and the specimen, thereby preventing the adverse effects of contact on test data accuracy while maintaining high measurement precision through optical field-based detection.
2Temperature
If liquid nitrogen is used to cool the bath, then the cooling effect is achieved, but the operation becomes hazardous and costly
Solution Approach 1:
The patent changes the cooling parameter from using liquid nitrogen to using a two-stage chiller unit with a refrigerant-based cooling system. This parameter change maintains the required low temperature capability for martensite phase transformation while eliminating the hazards and costs associated with liquid nitrogen handling, storage, and disposal.
Solution Approach 2:
The patent replaces the expensive and hazardous liquid nitrogen with a more economical refrigerant system that uses readily available, non-hazardous cooling media. The two-stage chiller unit provides cost-effective cooling through standard refrigeration cycles, eliminating the need for continuous purchase and handling of expensive liquid nitrogen.
3Temperature
If a hotplate is used to heat the bath, then heating is provided, but uniform and consistent temperature control is not achieved
Solution Approach 1:
The patent replaces the simple hotplate heating system with a computer-controlled thermal system that integrates heating elements, temperature sensors, and automated control algorithms. This substitution enables precise temperature control with uniform heat distribution through multiple heating zones and active feedback regulation, achieving the required temperature consistency for accurate transformation temperature measurement.
4Device complexity
If one specimen is tested at a time, then the test setup is simple, but the productivity is reduced
Solution Approach 1:
The patent merges multiple specimen testing capabilities into a single integrated apparatus. The fixture system can hold and test multiple specimens simultaneously, while the optical measurement system captures images of all specimens in a single frame. This combining of multiple testing functions into one system increases productivity without significantly increasing overall device complexity.
Solution Approach 2:
The patent creates a universal test apparatus that can handle multiple specimens through a multi-position fixture system. The camera-based measurement system provides multi-functionality by automatically tracking and measuring displacement of all specimens simultaneously. This universal design allows the same apparatus to test numerous specimens without requiring separate dedicated equipment for each specimen.
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 solution enables accurate and simultaneous testing of multiple shape memory metal alloy specimens, improving measurement precision and reducing costs by eliminating hazardous cooling agents and ensuring uniform temperature control, while allowing for the testing of multiple specimens concurrently.
Implementation Method 1
utilizing a two-stage chiller unit for precise temperature control
Implementation Method 2
A non-contact test apparatus and method using a vision-based optical system with a camera to track shape changes
Implementation Method 3
determining a transformation temperature of a shape memory metal alloy... the martensite-to-austenite transformation temperatures
Data Source
AI summary
A test apparatus and method for determining at least one characteristic of a test specimen. An exemplary test specimen is a shape memory metal alloy and an exemplary characteristic is a transformation temperature of the shape memory metal alloy. The test apparatus may include a chiller unit including a tank containing a chilling medium, such as isopropyl alcohol or denatured alcohol, which holds a removable fixture tray that can accommodate up to ten specimens, or more. The fixture tray holds the test specimens in an initial deformed condition, and the cooling medium may be gradually heated to induce transformation of the specimens. The test apparatus may include a vision-based optical system which includes a camera that tracks the specimens within its field of view.