Non-contact Magnetostrictive Stress Sensing with Magnetic Conditioning
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Solution Overview
Problem
Accurate measurement of stress in ferromagnetic materials is challenging due to small changes in magnetic permeability, and existing magnetostrictive sensors require expensive magnetic encoding or struggle with steady-state stress measurements, making them difficult to retrofit and costly.
Innovation Solution
A non-contact stress sensing system that induces a conditioning magnetic flux in ferromagnetic materials using coils driven by DC or AC sources, or permanent magnets, to enhance signal-to-noise ratio and linearity, allowing for accurate measurement of both transient and steady-state stresses without the need for expensive encoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanent magnetic encoding is applied to ferromagnetic material, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by inducing a conditioning magnetic flux into the ferromagnetic material before the actual stress measurement process. This pre-conditioning step establishes a stable magnetic baseline that enhances the sensitivity and precision of subsequent measurements without requiring permanent magnetic encoding or complex system modifications
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the magnetic flux conditions through conditioning coils. By changing the magnetic flux parameters (strength, distribution, temporal characteristics) before and during measurement, the system optimizes measurement precision adaptively without permanent material modification
2Measurement precision
If permanent magnetic encoding is applied to ferromagnetic material, then measurement precision is improved, but ease of manufacture and installation worsen
Solution Approach 1:
The system performs preliminary magnetic conditioning through coils rather than permanent encoding, allowing the material to remain in its original state. This enables easy installation and retrofitting on existing components without requiring material removal or permanent modification
Solution Approach 2:
The patent replaces the mechanical/permanent magnetic encoding process with an electromagnetic field-based conditioning approach. Instead of physically modifying the material with permanent magnets or encoded structures, the system uses controllable magnetic fields to achieve the same measurement enhancement, dramatically simplifying installation
3Ease of operation
If transient magnetic field induction is used, then ease of operation is improved, but measurement precision worsens for steady-state stress
Solution Approach 1:
The patent applies dynamics by implementing a dual-mode magnetic flux system that can adapt between transient and steady-state operation. The conditioning coils can apply time-varying magnetic fields for transient measurements while maintaining stable conditioned fields for steady-state measurements, providing operational flexibility without sacrificing precision in either regime
Solution Approach 2:
The system uses periodic action through AC-driven conditioning coils that can be modulated at different frequencies. For steady-state stress measurement, the periodic conditioning establishes a stable magnetic baseline that enhances measurement precision, while the same system can switch to transient modes when needed
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 system effectively measures stress with reduced current requirements, enabling operation in hazardous environments and simplifying installation, while providing improved signal linearity and reduced hysteresis, facilitating accurate detection of both transient and steady-state stresses.
Implementation Method 1
a magnetic flux device for inducing a first conditioning magnetic flux in ferromagnetic material
Implementation Method 2
Ferromagnetic materials have a magnetostrictive property that causes the materials to change shape in the presence of an applied magnetic field. The inverse is also true. When a force is applied to a ferromagnetic material, the magnetic properties, such as magnetic permeability, of the material change.
Data Source
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AI summary
A system for sensing stress in a ferromagnetic material is provided. The system includes at least one magnetic flux device configured to induce a conditioning magnetic flux in the ferromagnetic material. The system also includes a sensor positioned proximate to the ferromagnetic material. The sensor includes a core, at least one excitation coil configured to induce a second magnetic flux in the ferromagnetic material, and at least one detector configured to detect changes in the second magnetic flux.