Sensor Bond Integrity Verification via Thermal Shock
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Solution Overview
Problem
Conventional strain gauges face accuracy issues due to bond degradation between the sensor and the structure over time, caused by factors like fatigue and corrosion, leading to incorrect strain measurements and lack of warning for potential gauge failure, with current inspection methods being time-consuming and often inconclusive.
Innovation Solution
A method and system that apply a thermal shock to the sensor to determine bond integrity by measuring output signals from a Wheatstone bridge circuit, allowing for quick assessment of bond integrity between the sensor and the structure without substantially heating the structure, using techniques like electrical heating or photo flash heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional visual or tactile inspection methods are used to check bond integrity, then the inspection process is simple to perform, but the inspection is time-consuming and often inconclusive
Solution Approach 1:
The patent replaces mechanical inspection methods (visual/tactile examination) with a thermal shock-based measurement system that uses temperature changes and strain gauge readings to automatically detect bond integrity. The system applies a thermal shock to the sensor and measures the resulting temperature change rate and strain changes to determine bond status, eliminating the need for time-consuming manual inspection while providing objective, quantifiable results.
Solution Approach 2:
The sensor system performs self-diagnosis by monitoring its own thermal response and strain measurements. When a thermal shock is applied, the sensor measures its own temperature change rate and strain changes, automatically determining whether it is properly bonded to the structure without requiring external inspection equipment or personnel.
2Measurement precision
If thermal shock is applied to the sensor for bond integrity verification, then bond integrity can be determined accurately, but the structure may be substantially heated
Solution Approach 1:
The thermal shock is applied locally to the sensor rather than the entire structure. The heating element is positioned in direct thermal contact with only the sensor, creating a localized temperature increase that does not substantially heat the surrounding structure. This allows accurate bond integrity measurement while minimizing thermal impact on the structure.
Solution Approach 2:
The thermal shock is applied as a brief, periodic pulse rather than continuous heating. The system applies heat for a short duration (sufficient to create a measurable temperature change in the sensor) and then stops, allowing the structure to maintain its overall temperature while the sensor experiences the thermal shock needed for bond integrity verification.
3Reliability
If the sensor is heated to verify bond integrity, then bond status can be determined, but the sensor may provide incorrect strain measurements during normal operation
Solution Approach 1:
The thermal shock and bond integrity verification is performed as a periodic, temporary action rather than a continuous state. The sensor operates normally for strain measurement, then periodically undergoes brief thermal shock for bond verification. After verification, the sensor returns to normal operation with accurate strain measurement capability, as the bond status is confirmed without permanently altering the sensor's measurement properties.
Solution Approach 2:
The bond integrity verification is performed preliminarily before relying on strain measurements. By checking bond status through thermal shock first, the system ensures that subsequent strain measurements will be accurate, preventing incorrect readings from occurring in the first place.
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
Enables efficient and reliable verification of bond integrity, providing accurate strain measurements by distinguishing between fully bonded and partially debonded sensors through temperature or strain changes over time, thus enhancing the reliability of physical property measurements.
Implementation Method 1
heating a sensor bonded to a structure of interest and operably coupled to a measuring circuit during a sufficiently short time period to leave the structure in a substantially unheated state
Implementation Method 2
A sensing element for a strain gauge is conventionally implemented within a Wheatstone bridge circuit which converts the sensed resistance to a voltage signal
Data Source
AI summary
Methods and systems are disclosed for determining an amount of bond between a structure and sensor. A method may include heating a sensor that is operably coupled to a measuring circuit and then measuring an output signal over time. The method may further include determining, from the output signal, a percentage of bond integrity remaining between the sensor and the structure. A system may include a measurement circuit having a sensor operably coupled to a sensing system. The sensing system may be configured for applying a thermal shock to the sensor and subsequently measuring an output signal of the measuring circuit. The sensing system may also be configured for determining, from the output signal, an amount of bond between the sensor and the structure.