Rail Wear Detection via Mechanical Wave Interferometry

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Solution Overview

Problem

Existing methods for monitoring the physical condition of longitudinal elements, such as railway rails, only detect significant deterioration like cracks or breaks and fail to monitor wear at an early stage, and are prone to parasitic signals when sensors are placed away from the elements.

Innovation Solution

A method using an array of mechanical wave sensors placed directly on the longitudinal element, applying interferometry techniques to detect and process mechanical waves generated by the element itself, allowing for the extraction of information on wear by comparing virtual traces over different time intervals, and optionally using optical fiber with DAS technology for distributed sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors are placed away from the longitudinal element to avoid direct contact, then parasitic signals are reduced, but measurement precision deteriorates due to signal attenuation and interference from intermediate materials

Engineering Contradiction:
Improvesignal purityVSAvoidwear detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent uses interferometry as an intermediary processing technique to separate the useful signal from parasitic signals. By processing the signals from multiple sensors through interferometric methods, the system extracts the component related to the longitudinal element's condition while filtering out unwanted signals from the environment and intermediate materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor array is designed to serve multiple functions: detecting mechanical waves directly from the longitudinal element, filtering parasitic signals through spatial arrangement, and providing redundant measurements for improved accuracy. The same sensor array configuration works for both early wear detection and crack detection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If sensors are placed directly on the longitudinal element, then measurement precision improves by eliminating parasitic signals, but device complexity increases due to the need for direct contact sensor arrays

Engineering Contradiction:
Improvewear detection accuracyVSAvoidsensor array configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The monitoring system is divided into multiple independent sensor units that can be individually placed along the longitudinal element. Each sensor in the array performs the same function, allowing the system to achieve high measurement precision through spatial distribution without requiring each individual sensor to be complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses multiple copies of the same sensor type arranged in an array, rather than using a single complex sensor. This approach simplifies the individual sensor design while achieving high overall system precision through the collective measurement capability of multiple identical sensors processed through interferometry.

Inventive Principle:
Principle #26Copying

3Reliability

If only significant deterioration is detected, then false alarms are reduced, but early wear detection capability is lost

Engineering Contradiction:
Improvedetection accuracyVSAvoidearly intervention opportunity
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs partial detection by focusing on specific signal components related to wear through interferometric processing, rather than attempting to detect all possible conditions. This allows the system to detect early wear stages with high confidence by analyzing only the relevant signal portions that indicate wear, rather than requiring comprehensive detection of all deterioration types.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system performs preliminary detection of wear by continuously monitoring for early signs of deterioration before they develop into significant damage. The interferometric processing enables detection of subtle changes in mechanical wave propagation that indicate early wear, allowing preventive maintenance to be scheduled before critical failures occur.

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 early detection of wear and variation in the physical state of longitudinal elements by eliminating parasitic signals, providing continuous and robust monitoring with improved sensitivity and accuracy, suitable for both short-term and long-term analysis.

Implementation Method 1

detecting mechanical waves moving along the longitudinal element by means of an array of mechanical wave sensors placed along and in contact with the longitudinal element

Methodology Applied
Scientific EffectMechanical wave propagation: Vibration

Implementation Method 2

a processing step comprising the determination of a plurality of simplified traces, each simplified trace resulting from the interferometry of signals delivered by the sensors of the first pair

Methodology Applied
Scientific EffectInterferometry: Interference

Data Source

PatentEP4185845B1Method for monitoring the physical state of a rail
Publication Date: 2025.06.25 SERCEL SAS
  • EP4185845B1 patent drawingFigure 1a~1b
  • EP4185845B1 patent drawingFigure 2a~2c
  • EP4185845B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a method for monitoring the physical state of a longitudinal element (10) of a railway-type rail, the method comprising: - a step of detecting mechanical waves moving along the longitudinal element (10), in particular due to the passing of a train, by means of an array (14) of mechanical wave sensors placed along and in contact with the longitudinal element, the array (14) comprising at least one first pair (A) of sensors (1, 2) each positioned at one end of a first portion (10a) of the longitudinal element (10), and - a step of processing the signals emitted by the sensors (1, 2) in the array (12) of sensors, the processing step comprising the determination of at least one first interfered signal determined from signals provided by the sensors (1, 2) in the first pair (A) of sensors over a first predetermined period of time.