Chromium Strain Gauge Geometry for Low Transverse Sensitivity
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Solution Overview
Problem
Existing strain gauges with high gauge factors suffer from detection errors due to high transverse sensitivity ratios, which affect accuracy in strain detection.
Innovation Solution
A strain gauge design with a resistor made of chromium as a main component, where the line width and film thickness satisfy the relationship w≤0.0177t^2 + 0.1521t + 2.9541, ensuring a gauge factor of 5 or greater and a transverse sensitivity ratio of 70% or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gauge factor is increased to improve strain detection sensitivity, then the detection sensitivity is improved, but the transverse sensitivity ratio increases causing detection errors
Solution Approach 1:
The patent changes the physical parameters of the resistor by establishing a specific mathematical relationship between line width W and film thickness T (W ≤ 0.0177T² + 0.1521T + 2.9541). This parameter optimization allows the strain gauge to achieve a gauge factor of 5 or greater while maintaining transverse sensitivity ratio at 70% or less, thus improving detection sensitivity without compromising accuracy
Solution Approach 2:
The patent uses chromium (Cr) as the main component material for the resistor, which has specific piezoresistive properties. The Cr-based material provides both high gauge factor potential and, when combined with optimized dimensions, acceptable transverse sensitivity characteristics, resolving the contradiction between sensitivity and accuracy
2Reliability
If the line width and film thickness are optimized to reduce transverse sensitivity ratio, then the detection accuracy is improved, but the gauge factor may decrease
Solution Approach 1:
The patent simultaneously optimizes two parameters (line width W and film thickness T) with a mathematical relationship rather than independently adjusting them. This coupled parameter optimization ensures that when dimensions are adjusted to reduce transverse sensitivity, the gauge factor is maintained at 5 or greater through the coordinated change relationship defined by the formula
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 achieves a high gauge factor while significantly reducing the transverse sensitivity ratio, improving strain detection accuracy and output change, comparable to or exceeding that of commercially available strain gauges.
Implementation Method 1
The resistor is made of a material mainly composed of Cr. A line width W and a film thickness T of the resistor are in a relationship of satisfying an expression (1) below such that a strain gauge has a transverse sensitivity ratio of 70% or less and a gauge factor of 5 or greater.
Data Source
AI summary
The present strain gauge includes a substrate and a resistor formed on the substrate. The resistor is made of a material mainly composed of Cr. A line width W and the film thickness T of the resistor are in a relationship of satisfying an expression (1) below such that the strain gauge has a transverse sensitivity ratio of 70% or less and a gauge factor of 5 or greater. w≤0.0177t2+0.1521t+2.9541—(1). In the expression (1), w=log W and t=log T.