Autonomous Airfoil Inspection for Gas Turbine Surface Defects

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Solution Overview

Problem

Current inspection methods for airfoils in gas turbine engines are time-consuming and require significant equipment, often only performed during scheduled maintenance, making frequent inspections impractical and potentially unsafe.

Innovation Solution

An autonomous device with piezoelectric sensors and airfoil contacting members that move across the airfoil surface to detect defects, using electrical signals to identify topology changes and locate defects autonomously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual inspection methods are used, then inspection can be performed with simple equipment, but inspection time is excessive and frequency is limited

Engineering Contradiction:
Improveinspection frequencyVSAvoidinspection time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical inspection methods with an autonomous robotic system equipped with piezoelectric sensors. The robot autonomously traverses the airfoil surface, and the piezoelectric sensors detect surface topology changes through mechanical contact, converting mechanical deformation into electrical signals for defect identification. This substitution dramatically reduces inspection time while enabling frequent inspections.

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

2Measurement precision

If thorough inspection is performed, then defect detection accuracy is improved, but equipment complexity and time requirements increase

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs multiple piezoelectric sensors positioned at different locations on the robot body to inspect different regions of the airfoil simultaneously. Each sensor provides localized topological information, and the system integrates these local measurements to achieve comprehensive high-precision defect detection without requiring overly complex single-point inspection equipment.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The inspection system divides the airfoil surface into multiple inspection zones corresponding to different sensor positions. The robot systematically traverses these segmented zones, with each piezoelectric sensor independently monitoring its local area. This segmentation allows parallel defect detection across multiple regions, improving overall detection accuracy while maintaining manageable equipment complexity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If frequent inspections are conducted, then safety and longevity are improved, but time and operational downtime increase

Engineering Contradiction:
Improveengine safetyVSAvoidoperational downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The inspection robot is designed to autonomously navigate and inspect the airfoil without requiring human operators or extensive external equipment support. The self-contained system with integrated sensors and processing capabilities can perform thorough inspections quickly, enabling frequent monitoring that enhances engine safety and reliability while minimizing operational downtime through rapid autonomous execution.

Inventive Principle:
Principle #25Self-service

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 frequent, quick, and safe inspections of airfoils without requiring extensive downtime, improving safety and longevity by detecting micro-defects that could lead to catastrophic damage.

Implementation Method 1

Each of the plurality of topological sensors includes a piezoelectric sensor that generates an electrical signal indicative of a loading to the piezoelectric sensor

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4621404A1Autonomous inspection of a surface topology of an airfoil of a gas turbine engine
Publication Date: 2025.09.24 RTX CORP
  • EP4621404A1 patent drawingFigure 1
  • EP4621404A1 patent drawingFigure 2
  • EP4621404A1 patent drawingFigure 3A

AI summary

Apparatus and associated methods relate to autonomous devices (20) configured to inspect surface topologies of airfoils (18) of a gas turbine engine. The autonomous device (20) moves across the airfoil (18) while remaining coupled thereto while sensing the surface topology of the airfoil (18) using a plurality of topological sensors (32). Each of the plurality of topological sensors (32) includes a piezoelectric sensor (52) that generates an electrical signal indicative of a loading to the piezoelectric sensor (52), as well as an airfoil contacting member (54). The airfoil contacting member (54) extends between the piezoelectric sensor (52) and the airfoil (18) when the body (26) is coupled thereto. The airfoil contacting member (54) provides changes to the loading to the piezoelectric sensor (52) in response to changes in the surface topology of the airfoil (18) as the body (26) moves thereacross.