Rail Wheel Shape Detection Using Strain Gauges

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Solution Overview

Problem

Existing methods for detecting rail wheel shapes, such as those using load cells and acceleration sensors, are either overly complex or provide rough measurement results, failing to accurately assess wheel deformations and deviations from the ideal circular shape, which leads to increased stress on tracks and rolling stock and impaired transport quality.

Innovation Solution

A method and device utilizing a series of measuring elements attached to the rails, including strain gauges and piezoelectric sensors, to record force effects and movement signals, forming an information array that displays wheel shapes by breaking down rail depressions into relevant components near the wheel contact point, with signal evaluation based on transient rail reactions and wave propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If load cells are used to detect wheel shapes, then measurement capability is provided, but device complexity increases due to complicated design

Engineering Contradiction:
Improvewheel shape detection capabilityVSAvoiddesign complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical load cells with a simplified system using acceleration sensors and signal processing. Instead of directly measuring forces with complex mechanical transducers, the system uses accelerometers to detect rail vibrations and processes these signals mathematically to derive wheel shape information, thereby reducing device complexity while maintaining measurement capability.

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

2Device complexity

If acceleration sensors are used to detect wheel damage, then device simplicity is improved, but measurement precision deteriorates due to rough measurement results

Engineering Contradiction:
Improvedevice simplicityVSAvoidmeasurement result accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces signal processing algorithms and mathematical transformations as intermediaries between the simple acceleration sensors and the final wheel shape assessment. The raw acceleration signals are processed through spectral analysis, filtering, and comparison with reference patterns to extract precise wheel shape information, thereby maintaining device simplicity while achieving high measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If existing detection methods are used, then basic wheel damage detection is achieved, but detailed wheel shape assessment is lost

Engineering Contradiction:
Improvewheel damage detectionVSAvoidwheel shape detail information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the wheel circumference into multiple measurement points by using multiple acceleration sensors positioned at different locations on the rail. Each sensor captures vibrations from specific angular positions of the wheel, and the combined data reconstructs the complete wheel shape profile, thereby preserving detailed wheel shape information while maintaining reliable damage detection.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If simple alarm triggering is used for wheel deformations, then device operation is simplified, but measurement precision and detailed assessment are reduced

Engineering Contradiction:
Improveoperation simplicityVSAvoidwheel deformation quantification
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback system where measured wheel shape data is continuously compared with reference values and tolerance limits. The system provides graduated responses rather than simple alarm triggering - including visual displays of deviation magnitudes, priority classifications, and targeted notifications - thereby maintaining ease of operation while delivering precise wheel deformation assessment and detailed information.

Inventive Principle:
Principle #23Feedback

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

This approach provides precise detection of wheel shapes and deformations, enabling accurate assessment of wheel deviations, reducing stress on tracks and rolling stock, and improving transport quality by offering detailed control over wheel shape deviations.

Implementation Method 1

at least one measuring element is designed as a strain gauge

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Implementation Method 2

piezoelectric measuring elements are preferably applied in an embodiment of the device according to the invention

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

EP 0 282 615 A teaches an arrangement for detecting wheel damage with acceleration sensors mounted on a rail, which measure movements of the rail in the vertical direction

Methodology Applied
Scientific EffectAcceleration measurement: Accelerometer

Implementation Method 4

This rail reaction is associated with wave propagation in the rail (in and against the direction of travel), which has a moving node in the wheel contact point under consideration

Methodology Applied
Scientific EffectWave propagation: Waveguide

Data Source

PatentEP1883565B1Method and device for detecting wheel shapes of rail wheels
Publication Date: 2011.02.23 HOTTINGER BRUEEL & KJAER GMBH
  • EP1883565B1 patent drawingFigure 1
  • EP1883565B1 patent drawingFigure 2
  • EP1883565B1 patent drawing

AI summary

The invention relates to a method for detecting wheel shapes of rail wheels with the aid of a measuring strip which consists of a row of measuring elements which are applied to the rails and which absorb the dynamic effects and which guide the corresponding electric signals of an electronic evaluation device for representing the wheel shapes. The signals are derived from the measuring elements, which displace the rails in the vertical direction and, preferably, in the transversal direction, and then an information array is formed in the evaluation device from the signals, which corresponds at least to the periphery of the wheel. The periodic signal of the shapes of the wheel is evaluated with the aid of a Fourier development.