Ultrasonic Characterization of 3D Woven Composite Materials

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Solution Overview

Problem

Existing methods for characterizing composite materials, particularly 3D woven composites, face challenges due to strong ultrasonic wave absorption, leading to the absence of background echoes and phase shift issues, making it difficult to measure propagation speed and attenuation accurately.

Innovation Solution

A method involving the measurement of the travel time of a longitudinal ultrasonic wave by observing its origin, rather than the arch of the signal, using two plane ultrasonic sensors aligned and separated by a liquid, allows for precise determination of propagation speed and attenuation, overcoming issues with phase shift and deformation in complex materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic transmission/reception mode is used to measure propagation speed and attenuation, then measurement capability is provided, but background echo is not visible due to strong absorption in 3D woven composites

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidbackground echo visibility
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

A liquid coupling medium (water) is introduced between the ultrasonic transducer and the composite material part. This intermediary allows the ultrasonic wave to propagate through the liquid to reach the part and return, enabling measurement of propagation speed and attenuation without relying on background echo from within the highly absorbing composite material.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If conventional signal observation methods are used, then signal detection is possible, but phase shift and deformation of sinusoidal signal occur in thick or complex composite materials

Engineering Contradiction:
Improvesignal detectionVSAvoidsignal accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The travel time of the ultrasonic wave is measured by detecting the birth (onset) of the wave before any phase shift or deformation can occur during propagation through thick or complex composite materials. This preliminary timing measurement avoids the signal distortion problems that affect conventional methods.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If ultrasonic waves are used to characterize composite materials, then material properties can be determined, but measurement reliability decreases for thick or anisotropic materials due to strong absorption

Engineering Contradiction:
Improvematerial characterization capabilityVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The liquid coupling medium serves as an intermediary that facilitates reliable ultrasonic wave transmission to and from the composite material part, even when the part is thick or highly absorbing. This enables consistent measurement of propagation speed and attenuation across different material types and thicknesses.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By measuring the travel time at the birth of the wave before absorption and attenuation significantly affect the signal, the method achieves reliable measurements for thick or anisotropic composite materials that would otherwise be difficult to characterize.

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

This approach enables reliable characterization of composite materials, including 3D woven composites, by accurately determining fiber and resin content, porosity, and part dimensions, even in thick or anisotropic materials, providing precise information for material development.

Implementation Method 1

use an ultrasonic transducer in transmitter / receiver mode. The longitudinal wave is directed so as to propagate orthogonally to the two surfaces

Methodology Applied
Scientific EffectUltrasonic wave generation and detection: Ultrasound

Implementation Method 2

measure the propagation speed and the attenuation of a longitudinal ultrasonic wave passing through the room

Methodology Applied
Scientific EffectAcoustic wave propagation: Sound

Implementation Method 3

JPH 05172793 describes a method for characterizing a part comprising the determination of the attenuation of ultrasonic waves, by means of a pair of transducers separated by a liquid, such as water

Methodology Applied
Scientific EffectAcoustic wave transmission through liquid: Sound

Implementation Method 4

this solution is not suitable for materials which strongly absorb ultrasonic waves. This is the case for example with 3D woven composites whose structure is inhomogeneous and anisotropic

Methodology Applied
Scientific EffectUltrasonic wave absorption: Acoustic Absorption

Data Source

PatentEP2932255B1Method for characterising a part made of a composite material
Publication Date: 2019.06.26 SAFRAN AIRCRAFT ENGINES SAS
  • EP2932255B1 patent drawingFigure 1~3
  • EP2932255B1 patent drawingFigure 4~7
  • EP2932255B1 patent drawingFigure 8~10

AI summary

The invention consists in a method of characterizing a part made of composite material (30), the method comprising a step of determining a characteristic of a longitudinal ultrasound wave (41) traveling along a path within the part (30), and being characterized in that the travel time of a longitudinal ultrasound wave (42) transmitted by the part (30) is measured (E4).