Laser Ultrasonic Strain Estimation From Time-Domain Echoes

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Solution Overview

Problem

Existing methods for estimating accumulated strain in materials like steel during hot rolling processes are inefficient and prone to computational complexity and errors, hindering process optimization and material property prediction.

Innovation Solution

A method using laser ultrasonic (LUS) measurement equipment with generation and detection lasers and a detector to estimate accumulated strain by analyzing time-varying signals from ultrasonic wave echoes, eliminating the need for frequency domain conversions and utilizing shear wave packet echoes to determine strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods are used to estimate accumulated strain, then measurement capability is provided, but computational complexity increases and measurement precision decreases

Engineering Contradiction:
Improveaccumulated strain estimation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes only the necessary time-domain signal characteristics from ultrasonic wave echoes to estimate accumulated strain, eliminating the need for complete frequency domain conversions and complex signal processing steps, thereby reducing computational complexity while maintaining measurement precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of converting time-varying signals to frequency domain for analysis (conventional approach), the patent inverts the approach by directly analyzing the time-domain signal characteristics, specifically utilizing the time of flight and amplitude variations of ultrasonic wave echoes to determine accumulated strain, thus avoiding computational complexity of frequency transformations

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If conventional strain estimation methods are used, then strain data is obtained, but process optimization capability is hindered

Engineering Contradiction:
Improveprocess optimization efficiencyVSAvoidmaterial property prediction reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the estimated accumulated strain is used to control and optimize the steel rolling process parameters, creating a closed-loop system that continuously improves process efficiency and material property prediction reliability based on real-time strain measurements

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary estimation of accumulated strain during the rolling process to predict final material properties before the rolling is complete, enabling proactive process optimization and parameter adjustment to achieve desired material characteristics

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If frequency domain conversion is performed for strain estimation, then analysis is possible, but computational errors increase

Engineering Contradiction:
Improvestrain estimation accuracyVSAvoidcomputational errors
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts the essential strain information directly from time-domain signal characteristics (time of flight, amplitude variations) without performing frequency domain conversions, thereby eliminating computational errors associated with Fourier transforms and other frequency transformation methods while retaining the necessary measurement precision

Inventive Principle:
Principle #2Taking out (Extraction)

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 efficient and accurate estimation of accumulated strain, allowing for improved control of steel rolling processes and optimization of material properties, reducing computational complexity and enhancing process efficiency.

Implementation Method 1

providing a laser pulse onto a surface of the object by the generation laser such that a plurality of ultrasonic waves is created in the object

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

providing a laser pulse onto a surface of the object by the generation laser such that a plurality of ultrasonic waves is created in the object

Methodology Applied
Scientific EffectPhotoacoustic Effect: Photoacoustic Effect

Implementation Method 3

detecting the plurality of ultrasonic wave-echoes by use of the detection laser and the detector

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 4

detecting the plurality of ultrasonic wave-echoes by use of the detection laser and the detector, and therefrom obtaining a time-varying signal relating to an amplitude variation

Methodology Applied
Scientific EffectLaser Doppler Vibrometry: Laser Doppler Velocimetry

Data Source

PatentEP4707793A1A method for estimating an accumulated strain of an object
Publication Date: 2026.03.11 SSAB TECHNOLOGY AB
  • EP4707793A1 patent drawingFigure 1
  • EP4707793A1 patent drawingFigure 2
  • EP4707793A1 patent drawingFigure 3

AI summary

The present invention relates to a method for estimating an accumulated strain of an object by means of a laser ultrasonic (LUS) measurement equipment comprising a generation laser, a detection laser and a detector. The method comprises: - providing a laser pulse onto a surface of the object by the generation laser such that a plurality of ultrasonic waves is created in the object, - detecting the plurality of ultrasonic wave-echoes by use of the detection laser and the detector, and therefrom obtaining a time-varying signal relating to an amplitude variation of the plurality of ultrasonic wave-echoes in a time domain, - estimating the accumulated strain of the object by use of the time-varying signal.