Curved Calibration Block for Phased Array Ultrasonic Testing

Solution Overview

Problem

Phased array ultrasonic testing scanners face challenges in maintaining consistent signal amplitude across a wide scanning envelope, leading to irregular signal responses and incorrect sizing of target features due to varying primary wave front magnitudes at different angles, which existing calibration methods fail to fully address.

Innovation Solution

A calibration block with a semicircular acoustically transmissive calibration surface equidistant from the central axis, designed to maintain equal path lengths for primary wave fronts across a wide scanning envelope, allowing for improved signal sensitivity calibration and gain setting, particularly effective for angular scanning up to +90°>−90°.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the scanning envelope is increased to cover a wider angular range, then the coverage area is improved, but the signal amplitude consistency deteriorates due to varying primary wave front magnitudes at different angles

Engineering Contradiction:

Improvescanning envelope coverageVSAvoidsignal amplitude consistency

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The calibration surface is formed as a circular arc rather than a flat surface. This curvature is specifically designed to match the angular scanning pattern, ensuring that the path length from the transducer to the calibration surface remains substantially constant across all beam angles within the scanning envelope. This geometric configuration resolves the amplitude consistency issue by eliminating path length variations that would otherwise cause signal strength differences at different angles.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameter of the calibration surface from flat to circular arc with a specific radius. This parameter change transforms the path length characteristic from angle-dependent to angle-independent, allowing the calibration to maintain consistent signal amplitudes across the entire scanning envelope while covering a wide angular range.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional calibration methods using flat calibration surfaces are used, then the calibration process is simple, but the signal response irregularity worsens across wide scanning envelopes

Engineering Contradiction:

Improvecalibration block manufacturing simplicityVSAvoidsignal response consistency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The calibration surface is formed as a circular arc rather than a flat surface. This curvature is specifically designed to match the angular scanning pattern, ensuring that the path length from the transducer to the calibration surface remains substantially constant across all beam angles within the scanning envelope. This geometric configuration resolves the amplitude consistency issue by eliminating path length variations that would otherwise cause signal strength differences at different angles.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Area of stationary object

If the scanning envelope extends to wide angles (+90°>−90°), then the detection coverage is improved, but the path length variation across different beam angles increases causing calibration inaccuracies

Engineering Contradiction:

Improvedetection coverage areaVSAvoidcalibration accuracy

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The calibration surface is formed as a circular arc rather than a flat surface. This curvature is specifically designed to match the angular scanning pattern, ensuring that the path length from the transducer to the calibration surface remains substantially constant across all beam angles within the scanning envelope. This geometric configuration resolves the amplitude consistency issue by eliminating path length variations that would otherwise cause signal strength differences at different angles.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 calibration block ensures consistent signal response across a broader scanning envelope, enabling accurate detection of target features of the same size regardless of angle, simplifying the calibration process and improving the scanner's ability to visualize defects uniformly.

Implementation Method 1

The array of transducer elements may be selectively energised to launch a number of individual wave fronts into a test material. The wave fronts constructively and destructively combine within the material, resulting in a primary wave front which travels through the material and reflects off cracks, discontinuities or the like therein.

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

The calibration block may comprise an input surface for acoustically coupling to an ultrasound transducer of the ultrasonic testing scanner.

Methodology Applied

Scientific EffectAcoustic coupling: Sound

Data Source

PatentUS9140672B2Calibration block and method

Publication Date: 2015.09.22 AIRBUS OPERATIONS LTD

AI summary

A calibration block and method for sensitivity calibration. The calibration block has a curved calibration surface having a central axis and a surface for coupling to a transducer element of an angular scanning phased array ultrasonic testing scanner. The block is configured such that the surface positions the transducer such that its scanning axis is coaxial with the central axis of the curved calibration surface.