Impact-Echo Damage Detection Using Narrowband Elastic Waves

Solution Overview

Problem

Existing damage detection methods require dedicated sensors with flat frequency characteristics, limiting sensor options and increasing costs, especially when using high-frequency sensors like AE sensors with unknown frequency characteristics.

Innovation Solution

A method utilizing a band pass filter to convert elastic wave signals from AE sensors into a narrowband signal, allowing the extraction of an AC component of the envelope, which is then transformed to calculate the depth of damage using multiple reflections, enabling the use of less expensive sensors with unknown frequency characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dedicated sensors with flat frequency characteristics are used to estimate damage depth, then measurement precision is improved, but device cost increases and sensor selection is limited

Engineering Contradiction:

Improvedamage depth estimation accuracyVSAvoidsensor selection flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the parameter of frequency characteristics from requiring flat response to accepting unknown response. By introducing calibration processes and signal processing techniques that work with sensors having unknown frequency characteristics, the system enables use of diverse sensor types including AE sensors, acceleration sensors, and geophones, thereby improving adaptability while maintaining measurement precision through compensatory processing methods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention enables use of lower-cost sensors with unknown frequency characteristics instead of expensive dedicated sensors. By implementing calibration procedures and signal processing algorithms that compensate for unknown frequency responses, the system achieves accurate damage depth estimation using economical sensor options, reducing overall system cost while maintaining measurement accuracy

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If dedicated sensors with flat frequency characteristics are used to estimate damage depth, then measurement precision is improved, but device cost increases

Engineering Contradiction:

Improvedamage depth estimation accuracyVSAvoidsystem cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention changes the parameter of frequency characteristics from requiring flat response to accepting unknown response. By introducing calibration processes and signal processing techniques that work with sensors having unknown frequency characteristics, the system enables use of diverse sensor types including AE sensors, acceleration sensors, and geophones, thereby improving adaptability while maintaining measurement precision through compensatory processing methods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention enables use of lower-cost sensors with unknown frequency characteristics instead of expensive dedicated sensors. By implementing calibration procedures and signal processing algorithms that compensate for unknown frequency responses, the system achieves accurate damage depth estimation using economical sensor options, reducing overall system cost while maintaining measurement accuracy

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 accurate estimation of damage depth using less expensive sensors with unknown frequency characteristics, improving sensor flexibility and reducing costs while maintaining the accuracy of conventional impact echo methods.

Implementation Method 1

a detector configured to detect an AC component of an envelope using one or more elastic waves generated by an impact on the structure

Methodology Applied

Scientific EffectElastic wave detection: Acoustic Emission

Implementation Method 2

A method utilizing a band pass filter to convert elastic wave signals from AE sensors into a narrowband signal

Methodology Applied

Scientific EffectBand pass filtering: Filter (electronic)

Implementation Method 3

a spectrum calculator configured to calculate a frequency spectrum based on the detected AC component of the envelope

Methodology Applied

Scientific EffectFrequency spectrum analysis:

Implementation Method 4

enabling the use of less expensive sensors with unknown frequency characteristics... calculate the depth of damage inside the structure based on the frequency spectrum

Methodology Applied

Scientific EffectMultiple reflections: Echo

Data Source

PatentUS20250290825A1Damage detection apparatus, damage detection system and damage detection method

Publication Date: 2025.09.18 KK TOSHIBA

AI summary

According to one embodiment, a damage detection apparatus according to an embodiment includes a detector, a spectrum calculator, and a depth calculator. The detector detects an Alternating Current (AC) component of an envelope using one or more elastic waves generated by an impact on a structure. The spectrum calculator calculates a frequency spectrum based on the detected AC component of the envelope. The depth calculator calculates a depth of damage inside the structure based on the frequency spectrum.