Magnetoelastic Strain Sensor with Compliance Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetoelastic strain sensors face limitations due to magnetic saturation at low strains, which restricts their dynamic range and sensitivity, making them less effective for measuring broader strain ranges.
Innovation Solution
A strain sensor design incorporating a magnetoelastic material with a compliance element that distributes strain non-uniformly, preventing magnetic saturation and allowing for tunable sensitivity and dynamic range through a biasing magnetic field, enabling measurement of strains beyond the typical saturation point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If magnetoelastic material is used for strain sensing, then wireless sensing capability is achieved, but magnetic saturation occurs at low strains limiting dynamic range
Solution Approach 1:
The sensor is divided into two functional segments: a resonator segment for magnetic field interaction and wireless sensing, and a compliance element segment for mechanical strain accommodation. This segmentation allows each part to perform its specialized function optimally—the resonator detects strain through magnetic properties while the compliance element prevents saturation by distributing strain non-uniformly
Solution Approach 2:
The compliance element acts as an intermediary between the magnetoelastic resonator and the external strain source. It mediates the strain transmission by distributing it non-uniformly, ensuring the resonator experiences appropriate strain levels for detection without reaching magnetic saturation, thus expanding the usable dynamic range
2Device complexity
If uniform strain is applied to magnetoelastic material, then simple sensor design is achieved, but magnetic saturation limits sensitivity
Solution Approach 1:
The compliance element is designed with specific geometric features (such as varying cross-section or material properties) that create non-uniform strain distribution locally within the resonator. This local quality variation ensures optimal strain levels are maintained in the magnetoelastic material for maximum sensitivity without requiring complex external control mechanisms
3Manufacturing precision
If compliance element with lower stiffness is used, then dynamic range is expanded, but sensor structure becomes more complex
Solution Approach 1:
The compliance element's stiffness parameter is specifically engineered to be lower than the resonator's stiffness. This parameter change allows the compliance element to deform more under applied strain, distributing the strain non-uniformly and preventing magnetic saturation in the resonator, thereby expanding the dynamic range with a relatively simple structural modification
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 design extends the dynamic range of magnetoelastic strain sensors, allowing for accurate measurement of strains up to 1.05 mstrain and beyond, with sensitivity maintained across the range, suitable for applications like medical implants and structural monitoring.
Implementation Method 1
when subjected to an applied strain, a magnetoelastic material exhibits the Villari effect, in which the applied strain induces magnetization in the material
Implementation Method 2
In the presence of a magnetic field, a magnetoelastic material exhibits the Joule magnetostriction effect, in which the magnetic field induces strain in the material
Implementation Method 3
When an alternating magnetic field is applied to a magnetoelastic material, mechanical vibration is induced via the Joule effect and results in strain-induced material magnetization via the Villari effect
Data Source
AI summary
A strain sensor having an active area that includes a magnetoelastic resonator and spring configured so that the spring undergoes a greater amount of strain than the resonator when the sensor is under load. The sensor is anchored at opposite ends of the active area to a substrate for which strain is to be measured. An interrogating coil is used for wireless sensor readout. A biasing magnet may be included to provide a desired sensor response for the particular application of the sensor. The strain sensor may be implemented as a differential strain sensor that includes a second, strain-independent reference resonator.