Inductive Hall Current Residual Stress Profiling

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Solution Overview

Problem

Existing methods for determining residual stress profiles in materials are limited by variability in material properties and stress factors, making it difficult to predict the remaining service life and detect flaws effectively.

Innovation Solution

A system and method using high frequency inductive sensing of a Hall current, involving alternating current injection electrodes and sensing coils, to measure the Hall coefficient, which is sensitive to charge carrier density and indicative of material properties like residual stress, elastic strain, and plastic strain, allowing for accurate residual stress profiling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic NDE is used to detect residual stress profiles, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveresidual stress detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the measurement function by separating current injection (via electrodes) from field sensing (via coils), allowing independent optimization of each subsystem while achieving comprehensive material characterization through multiple measurement modes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electromagnetic NDE system achieves multi-functionality by using the same basic apparatus to perform residual stress profiling, conductivity measurement, permeability assessment, thickness gauging, and flaw detection, eliminating the need for separate specialized devices for each measurement type

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

2Measurement precision

If Hall coefficient measurement is used for residual stress assessment, then measurement precision is improved, but difficulty of detecting and measuring increases

Engineering Contradiction:
ImproveHall coefficient measurement accuracyVSAvoidHall current detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system replaces direct electrical contact measurement with inductive sensing using sensing coils that detect Hall currents wirelessly through electromagnetic induction, eliminating contact issues and reducing measurement difficulty while maintaining high precision

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

Solution Approach 2:

The sensing coils act as intermediaries between the Hall current source and the measurement instrument, transferring information through electromagnetic fields and enabling non-contact measurement that simplifies the detection process

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reliable detection of residual stress and separation of elastic and plastic strains, providing accurate material property determination and extending the service life prediction of materials in high-stress environments.

Implementation Method 1

inductively sensing, using a first sensing coil and a second sensing coil, a Hall current for the portion of the material

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a Hall current created by the alternating current and a magnetic field perpendicular to the alternating current

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3415902B1System for nondestructive residual stress profiling using inductive sensing
Publication Date: 2023.12.27 ROLLS ROYCE CORP
  • EP3415902B1 patent drawingFigure 1~2
  • EP3415902B1 patent drawingFigure 3
  • EP3415902B1 patent drawingFigure 4

AI summary

A system may include a first injection electrode, a second injection electrode, a first sensing coil, and a second sensing coil. The first injection electrode and the second electrode may each be configured to contact a material and conduct an alternating current through a portion of the material. The first sensing coil and a second sensing coil may each be configured to inductively sense a Hall current created by the alternating current and a magnetic field perpendicular to the alternating current. The first sensing coil and the second sensing coil may be coupled in series.