Impedance-Based Crack Detection in Conductive Materials

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Solution Overview

Problem

Current methods for detecting cracks in conductive or semiconductive materials, such as ceramic body plating, are often expensive, bulky, and not portable, making them inefficient for real-time structural integrity verification.

Innovation Solution

A measurement system utilizing a voltage source with a fixed resistor to determine equivalent impedance, allowing for cost-effective and portable crack detection by comparing measured impedances with control impedances from intact materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If X-ray scanning or X-ray CT scanning is used to detect cracks in materials, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecrack detection accuracyVSAvoidscanner size and complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical X-ray scanning systems with an electrical impedance measurement system. Instead of using heavy X-ray equipment to detect cracks, the invention uses electrical contacts and impedance measurements to identify structural damage, achieving comparable detection capability with significantly reduced device complexity and portability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the measurement parameter from physical imaging (X-ray) to electrical property measurement (impedance). By measuring electrical impedance between contacts on the material surface, the system can detect cracks and defects without requiring complex imaging equipment, thus resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If X-ray scanning is used for crack detection, then measurement precision is improved, but portability deteriorates

Engineering Contradiction:
Improvecrack detection accuracyVSAvoidscanner portability
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent substitutes heavy mechanical X-ray scanning equipment with a lightweight electrical measurement system. The impedance-based detection method requires only simple electrical contacts and measurement circuits, making the system portable while maintaining crack detection accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses simple, inexpensive electrical contacts and basic measurement circuits instead of expensive, heavy X-ray equipment. This approach achieves the same functional goal with minimal weight and maximum portability, effectively resolving the portability contradiction.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If traditional impedance measurement systems are used, then measurement capability is achieved, but device complexity and cost increase

Engineering Contradiction:
Improveimpedance measurement capabilityVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential measurement capability from complex traditional impedance systems. By using simple voltage sources, basic voltage dividers, and straightforward impedance calculations, the invention achieves accurate measurements without the complexity of traditional multi-probe arrays and sophisticated control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex traditional impedance measurement equipment with simple, inexpensive components such as basic voltage sources, resistors, and voltage measurements. This simplification maintains measurement precision while dramatically reducing device complexity and cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 portable detection of cracks in materials by using a voltage source with a fixed resistor to measure equivalent impedance, reducing costs and equipment size compared to traditional methods like X-ray scanning.

Implementation Method 1

determining a current flowing through the tested material based on a voltage drop across the fixed resistor

Methodology Applied
Scientific EffectOhm's Law: Ohm's Law

Implementation Method 2

determining an equivalent impedance associated with the tested material based on the current and a measured voltage in response to the voltage signal

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Impedance Tomography

Data Source

PatentEP3555606B1Verifying structural integrity of materials using reference impedance
Publication Date: 2022.08.17 3M INNOVATIVE PROPERTIES CO
  • EP3555606B1 patent drawingFigure 1
  • EP3555606B1 patent drawingFigure 2
  • EP3555606B1 patent drawingFigure 3

AI summary

A measurement system may include a set of drive electrical contacts including a force electrical contact and a return electrical contact electrically coupled to a tested material, a measurement electrical contact electrically coupled to the tested material, a return node, a voltage source, and a control module. A circuit path between the voltage source and the return node may include a fixed resistor and the tested material. The control module may be configured to cause the voltage source to apply a voltage signal to the force electrical contact, cause a voltage drop across the fixed resistor to be measured, cause a measured voltage to be measured using the measurement electrical contact, determine a measured equivalent impedance of the tested material associated with the measurement electrical contact based on the voltage drop across the fixed resistor and the measured voltage, and determine whether the tested material includes a crack or other defect based on the measured equivalent impedance.