Electrostatic Probe for Non-Intrusive Composite Inspection
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Solution Overview
Problem
Current non-destructive inspection methods are inadequate for accurately detecting delamination and other imperfections in composite materials, which are increasingly used in safety-critical applications due to their design flexibility and strength, but are vulnerable to damage like micro-cracking and delamination, leading to longer damage assessment times compared to metallic structures.
Innovation Solution
An apparatus and method utilizing a probe with a sensor unit and oscillator circuit that generates an electrostatic field, featuring concentric electrodes insulated from each other, which changes oscillation frequency when imperfections are present, allowing for non-intrusive detection of macroscopic imperfections in metallic, non-conductive, and composite materials by monitoring the tuning frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic pulse echo inspection is used to detect imperfections in composite materials, then detection capability for air boundaries and delamination is improved, but the method cannot accurately detect thinning of composite material
Solution Approach 1:
The patent replaces the ultrasonic mechanical wave-based inspection system with an electrical measurement system. The probe applies a voltage across the composite material and measures current flow, substituting mechanical energy with electrical energy to achieve more reliable detection of both delamination and thinning imperfections
Solution Approach 2:
The patent changes the measurement parameter from ultrasonic echo time to electrical resistance/conductivity. By measuring the electrical properties of the composite material, the system can detect both air boundaries (delamination) and material thinning, as both imperfections affect electrical conductivity differently than ultrasonic wave propagation
2Measurement precision
If tap-test inspection with accelerometer is used to detect imperfections, then contact time measurement is improved, but the method provides very limited information on type and exact position of imperfection
Solution Approach 1:
The patent replaces the mechanical tap-test system with an electrical measurement system. Instead of mechanically tapping and measuring contact time or sound frequency, the system applies voltage and measures current flow patterns, providing comprehensive information about imperfection type, location, and characteristics without mechanical contact
Solution Approach 2:
The patent introduces electrical current as an intermediary to probe the composite material structure. The current flow serves as a mediator that reveals information about internal imperfections (delamination, thinning) by how it passes through or around the defects, providing detailed spatial and typological information
3Measurement precision
If x-ray examination is used to detect flaws in test objects, then detection of crushed core and water accumulation is improved, but the method cannot detect air inclusions and requires protective measures
Solution Approach 1:
The patent replaces the x-ray electromagnetic radiation system with an electrical measurement system operating at lower energy levels. By measuring electrical conductivity patterns, the system can detect all types of imperfections including air inclusions, without the harmful radiation effects of x-rays
Solution Approach 2:
The patent changes the detection parameter from x-ray absorption to electrical conductivity. Different imperfections (water, crushed core, air inclusions) affect electrical conductivity in distinct ways, allowing comprehensive detection without the limitations and hazards of x-ray imaging
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 accurate and efficient detection of imperfections such as early corrosion, cracks, and delamination, even in hidden areas, with high resolution and independence from the material type, facilitating quicker and more precise damage assessment in composite structures.
Implementation Method 1
The sensor unit comprises at least two concentric electrodes, and insulation means that insulate the at least two concentric electrodes from each other, wherein the at least two concentric electrodes are adapted to generate an electrostatic field
Data Source
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AI summary
The invention is related to an apparatus 100, and a method of use of the apparatus 100, for non-intrusively detecting imperfections in a test object 150 made from metallic, non-conductive, and/or composite materials. The apparatus 100 comprises a probe 105 that is adapted to be moved over a test object 150 made from metallic, non-conductive, and/or composite materials. The probe 105 comprises a sensor unit 110 with at least two concentric electrodes that are adapted to generate an electrostatic field, and an oscillator circuit 130 that is adapted to oscillate with an associated oscillation frequency 160 in response to a test object 150 being located in the electrostatic field. The apparatus 100 further comprises an evaluation unit 140 that is adapted to enable localisation of an imperfection in a test object 150 made from metallic, non-conductive, and/or composite materials based on the associated oscillation frequency 160.