Eddy-Current Flaw Detection on Curved Surfaces

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Solution Overview

Problem

Eddy-current flaw detection in complex, three-dimensionally curved surfaces, such as the bottom portion of a reactor pressure vessel, faces challenges with high inspection accuracy due to varying lift-off distances, leading to reduced sensitivity and false signal occurrences, especially when numerous inspection points require a time-consuming teaching procedure for contact condition selection.

Innovation Solution

An eddy-current flaw detector system that includes a profilometer for surface shape data acquisition, a trace data calculator to determine optimal probe positions and orientations, a gap evaluation calculator to assess the gap between the probe and surface, and a flaw detection data analyzer to evaluate the presence of flaws, allowing for efficient detection without extensive teaching processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional teaching procedure is used to select contact condition for each inspection point, then flaw detection accuracy is improved, but inspection time increases significantly

Engineering Contradiction:
Improveflaw detection accuracyVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-calculating optimal probe positions and orientations for all inspection points before actual flaw detection begins. The trace data calculator computes three-dimensional trace data in advance, and the teaching procedure automatically determines contact conditions for multiple inspection points beforehand, eliminating the need for time-consuming manual teaching during actual inspection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces manual mechanical teaching operations with automated computational systems. The trace data calculator and teaching procedure automation substitute human operators physically adjusting probe positions with computer-based automatic calculation and control, significantly reducing inspection time while maintaining detection accuracy.

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

2Area of stationary object

If inspection probe is moved along complex curved surface, then coverage of inspection area is improved, but lift-off distance increases and detection sensitivity decreases

Engineering Contradiction:
Improveinspection coverage areaVSAvoiddetection sensitivity
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts probe position and orientation based on the complex curved surface geometry. The trace data calculator computes optimal three-dimensional positions and attitudes for each inspection point, allowing the probe to adapt its configuration to maintain minimal lift-off distance while covering the entire complex surface area.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention applies local quality by optimizing probe positioning for each specific inspection point on the complex surface. Instead of using a uniform approach, the system calculates individualized trace data for each point, ensuring the probe maintains optimal contact conditions (minimal lift-off) at each location while still achieving comprehensive coverage.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If minimal lift-off is maintained for accurate detection, then detection sensitivity is improved, but inspection of complex surfaces becomes time-consuming

Engineering Contradiction:
Improvedetection sensitivityVSAvoidinspection efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The invention replaces manual mechanical adjustment operations with automated computational systems. The trace data calculator and automated teaching procedure substitute human operators physically adjusting probe positions with computer-based automatic calculation and control, significantly reducing inspection time while maintaining detection sensitivity through minimal lift-off.

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

Solution Approach 2:

The system performs preliminary calculation of optimal probe positions and orientations for all inspection points before actual flaw detection begins. This advance preparation eliminates the need for time-consuming manual teaching during inspection, allowing the system to maintain minimal lift-off for high sensitivity while achieving rapid inspection of complex surfaces.

Inventive Principle:
Principle #10Preliminary action

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 rapid and accurate eddy-current flaw detection on complex surfaces with minimal lift-off, reducing the time required for inspections and improving the reliability of detected flaws by analyzing gap evaluation results.

Implementation Method 1

a profilometer configured to acquire surface shape data of an object to be inspected

Methodology Applied
Scientific EffectSurface shape measurement:

Implementation Method 2

an eddy-current flaw detector... an inspection probe... configured to detect an eddy-current

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP3220139B1Eddy-current flaw detection device and eddy-current flaw detection method
Publication Date: 2020.01.29 KK TOSHIBA
  • EP3220139B1 patent drawingFigure 1
  • EP3220139B1 patent drawingFigure 2A~2B
  • EP3220139B1 patent drawingFigure 3A~3B

AI summary

An eddy-current flaw detector includes a trace data calculator configured to calculate each coordinate with respect to flaw detection points on which an inspection probe is used upon performing an eddy-current testing based on an inputted condition of eddy-current flaw detection and surface shape data of an inspection-object surface measured by a profilometer, and to calculate a normal vector of each flaw detection point; a gap evaluation calculator configured to acquire an evaluation result on a gap between the inspection-object surface and the inspection probe for each flaw detection point; a flaw detection data collector configured to acquire flaw detection data of an inspection object for each flaw detection point; a flaw detection data analyzer configured to evaluate presence/absence of a flaw in the inspection-object surface based on the flaw detection data of the inspection object and the evaluation result on the gap for each flaw detection point.