Rotated Flat-Bottom Hole Samples for Ultrasonic Crack Diffraction

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Solution Overview

Problem

Existing ultrasonic inspection methods struggle to effectively detect mal-oriented cracks in rotating disk components due to minimized reflection and enhanced diffraction, as traditional flaws like flat bottom holes are not suitable for simulating these cracks, making it difficult to assess detection capability accurately.

Innovation Solution

The development of artificial diffraction inspection samples with flat bottom holes located in the axial-radial plane and rotated complimentary surfaces to mimic mal-oriented cracks, ensuring consistent diffraction response and easier fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional flat bottom holes are used for ultrasonic calibration and POD purposes, then fabrication is easy and accepted for volumetric flaws in reflection mode, but they are not suitable for simulating mal-oriented cracks which primarily diffract acoustic energy

Engineering Contradiction:

Improvefabrication easeVSAvoidflaw detection accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent creates artificial flaws that copy the diffraction characteristics of mal-oriented cracks by using flat bottom holes with specifically oriented bottom surfaces. The bottom surface of each flat bottom hole is rotated to match the orientation angle of the target crack, thereby replicating the diffraction response of the actual flaw while maintaining the fabrication simplicity of drilled holes.

Inventive Principle:

Principle #26Copying

2Measurement precision

If cracks are used as POD samples to reflect real inspection behavior for mal-oriented cracks, then detection capability assessment is accurate, but fabrication of samples with internal cracks is nearly impossible

Engineering Contradiction:

ImprovePOD assessment accuracyVSAvoidsample fabrication difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of fabricating actual cracks which is nearly impossible, the patent creates copies of crack diffraction responses using flat bottom holes. By orienting the bottom surface of the holes to match crack angles and positioning them to simulate crack locations, the artificial flaws replicate the diffraction behavior of real cracks, enabling accurate POD assessment without the fabrication complexity of actual cracks.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent changes the geometric parameters of the artificial flaws by rotating the bottom surfaces of flat bottom holes to specific orientation angles that match the target crack orientations. This parameter adjustment allows the simple-to-fabricate holes to produce diffraction responses equivalent to mal-oriented cracks, bridging the gap between fabrication ease and measurement accuracy.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If mal-oriented cracks are detected using diffraction mode, then detection of axial-radial plane cracks is possible, but the returned signals are weaker compared to reflection mode

Engineering Contradiction:

Improvecrack orientation detection capabilityVSAvoidsignal strength

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent creates artificial flaws that copy the diffraction response characteristics of mal-oriented cracks, including the weaker signal strength inherent to diffraction mode. By using flat bottom holes with oriented bottom surfaces, the system maintains the ability to detect various crack orientations while providing known reference signals for POD assessment, even though these signals are weaker than reflection mode signals.

Inventive Principle:

Principle #26Copying

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

Facilitates accurate detection of mal-oriented cracks by maintaining consistent diffraction response and simplifying the fabrication process, thereby improving the Probability of Detection (POD) assessment.

Implementation Method 1

the acoustic energy is primarily diffracted from the edge of the crack and returned to the transducer. The diffraction response is based on the crack effective radius and the sound path incidence angle on the crack.

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS20260079132A1Artificial flaw method for ultrasonic diffraction inspection sample

Publication Date: 2026.03.19 RTX CORP

AI summary

An artificial diffraction inspection sample including a sample component having a component body with an exterior surface; and a complimentary flat bottom hole formed in the component body, the complimentary flat bottom hole comprising a complimentary bottom surface with a complimentary incidence angle, the complimentary bottom surface being rotated around an acoustic path vector; wherein the complimentary bottom of the complimentary flat bottom hole represents an axial-radial crack.