Capacitive Sensor Fatigue Measurement Elastomer
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Solution Overview
Problem
Existing methods for monitoring elastomeric material fatigue, such as resonant sensors and dipoles, often require additional conductive elements that can compromise the structural integrity of components and are costly to implement, with limited sensitivity in predicting remaining service life due to reliance on the real part of the dielectric constant.
Innovation Solution
A capacitive sensor system with a two-pole, interdigital conductor structure is applied to the elastomeric component's surface, allowing electric field lines to penetrate and measuring both real and imaginary parts of impedance over a frequency range to determine the loss angle, which is more sensitive for fatigue assessment, enabling wireless excitation and universal adaptation to different materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resonant sensors or dipole structures are embedded in the elastomeric component, then fatigue monitoring capability is achieved, but structural integrity is compromised due to differences in modulus of elasticity and additional integration complexity
Solution Approach 1:
The patent replaces mechanical/embedded sensor structures with electromagnetic field-based measurement. Instead of embedding conductive structures that mechanically interact with the elastomer, the invention uses capacitive sensor elements that measure fatigue through electromagnetic field interactions with the elastomer's dielectric properties, eliminating mechanical integration issues
Solution Approach 2:
The invention measures fatigue by detecting changes in the complex dielectric constant (both real and imaginary parts) of the elastomer material. This parameter-based approach allows non-contact measurement that doesn't compromise structural integrity, as the measurement is based on electromagnetic field interactions rather than mechanical integration
2Ease of operation
If metallic conductors are integrated into dynamically loaded regions, then electrical connectivity is achieved, but fatigue resistance is reduced due to limited load cycle承受能力
Solution Approach 1:
The patent replaces metallic conductive structures with capacitive sensor elements that use electromagnetic fields for measurement. This substitution eliminates the need for metallic conductors in dynamically loaded regions, thereby maintaining electrical connectivity functionality while significantly improving fatigue resistance by avoiding metal fatigue issues
3Device complexity
If only the real part of the dielectric constant is measured, then measurement simplicity is maintained, but sensitivity for predicting remaining service life is insufficient
Solution Approach 1:
The invention measures both the real part (ε') and imaginary part (ε'') of the complex dielectric constant. The imaginary part, which represents dielectric loss, provides additional sensitive information about material fatigue and degradation. This dual-parameter measurement approach significantly improves service life prediction sensitivity while maintaining manageable measurement complexity through standard impedance spectroscopy techniques
4Measurement precision
If dipole material with different dielectric properties is used, then detectability by transmitter-receiver is improved, but material selection complexity and costs increase
Solution Approach 1:
The invention uses the elastomer's own dielectric properties for measurement without requiring additional dipole materials with specially matched dielectric characteristics. The capacitive sensor elements measure the natural dielectric response of the elastomer material itself, eliminating the need for complex material pairing and selection processes while maintaining high detectability
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
This approach enhances the accuracy and quality of fatigue assessment, allowing for non-destructive, cost-effective, and space-saving monitoring with increased sensitivity, suitable for both recurring and permanent inspections, and adaptable to various elastomeric products.
Implementation Method 1
a capacitive sensor element is arranged on a surface of an elastomer body of the elastomer product in such a way that electric field lines of the capacitive sensor element can penetrate into the elastomer body
Implementation Method 2
the elastomer to be monitored exhibits space charge relaxation and orientation relaxation upon electrical excitation
Implementation Method 3
the elastomer to be monitored exhibits space charge relaxation and orientation relaxation upon electrical excitation
Implementation Method 4
A programmable impedance spectrometer or the like can detect or measure the impedance of the sensor conductor structure across the frequency range
Data Source
Figure 1~2
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Figure 4
AI summary
Method and apparatus for fatigue measurement of an elastomer product (2), wherein a fatigue sensor (10) with at least one capacitive sensor element (12) is arranged on a surface of an elastomer body (20) of the elastomer product (2) such that the electric field lines (B) of the capacitive sensor element (12) can penetrate the elastomer body (20), comprising at least the steps of: • Exciting (100) the capacitive sensor element (12), preferably wirelessly, • Detecting (200) both the real part and the imaginary part of the impedance of the capacitive sensor element (12) over a frequency range; • Determining (300) the loss angle of the impedance over the frequency range; • Compare (400) the frequency-dependent impedance with at least one predetermined frequency-dependent impedance of a known fatigue state of the elastomer body (20); and • Determine (500) a degree of fatigue of the elastomer body (20) from the result of the comparison (400).