Method for non-destructively testing objects, in particular planar objects, made of a fibre-reinforced composite material

Patent metadata

Field	Value
Publication number	US-12467904-B2
Application number	US-202118002410-A
Country	US
Kind code	B2
Filing date	Jun 16, 2021
Priority date	Jun 18, 2020
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A method is provided in which an ultrasonic signal is generated as an electromagnetic ultrasonic signal by the at least one transmitting transducer, which is in the form of an EMUS transducer, by means of a conductive layer arranged on the surface of the object or in said object. An evaluation apparatus is used to utilize the ultrasonic signal detected by the at least one receiving transducer, which is in the form of an EMUS transducer, in order to determine a flaw in the form of a delamination, a porefield or other such two-dimensional inhomogeneities.

First claim

The invention claimed is:

1 . A method for nondestructively testing objects made of a fiber composite material which is in at least single-layer form, the method comprising:
generating, via a transmitting transducer in the form of an EMUS transducer, an electromagnetic ultrasonic signal in the object by a conductive layer arranged on a surface of the object or in the object, detecting propagation of the ultrasonic signal in the object by a receiving transducer in the form of an EMUS transducer; determining, by an evaluation apparatus utilizing the ultrasonic signal detected by the at least one receiving transducer, a flaw in the form of a delamination, a porefield or other such two-dimensional inhomogeneities; wherein the flaw is determined by virtue of a local phase velocity and/or a local wavelength of the received ultrasonic signal at a location of the receiving transducer being determined in the evaluation apparatus and used to determine the depth of the flaw.

2 . The method as claimed in claim 1 , wherein the testing method is performed without coupling means.

3 . The method as claimed in claim 1 , wherein the transmitting transducer is used to produce a guided wave.

4 . The method as claimed in claim 1 , wherein a material-specific correlation of a depth of the flaw with the phase velocity and/or with the wavelength is used to determine the flaw depth.

5 . The method as claimed in claim 4 , wherein the flaw is determined by performing at least one spatial Fourier transformation of the detected ultrasonic signal over at least part of a measuring section of the receiving transducer.

6 . The method as claimed in claim 5 , wherein a maximum of the wavenumber and/or the phase velocity is determined from a consideration of the ascertained spectra at different times.

7 . The method as claimed in claim 1 , wherein flaws at a depth of between 0% and up to 50% of a thickness of the object are tested by using the A0 mode of a Lamb wave.

8 . The method as claimed in claim 1 , wherein flaws are tested by initially using an S0 mode of a Lamb wave, an A0 mode that results from the S0 mode in a region of a flaw additionally being used for evaluation.

9 . The method as claimed in claim 1 , wherein the receiving transducer is moved in the direction of propagation of the ultrasonic signal and/or a linear array comprising one or more receiving transducers is used.

10 . An apparatus for performing the method as claimed in claim 1 , the apparatus comprising:
a transmitting transducer, a receiving transducer, and an evaluation apparatus, wherein the receiving transducer detects various wavelengths.

11 . The apparatus as claimed in claim 10 , wherein the receiving transducer comprises:
at least one magnetization device, and at least one conductor, which merely comprises a conductor loop, formed by one or more windings, with supply and return paths.

12 . The apparatus as claimed in claim 11 , wherein during operation the supply and return paths are arranged parallel to a surface of the object to be tested and above one another with reference thereto.

13 . The apparatus as claimed in claim 12 , further including a plurality of receiving transducers arranged in succession in a direction of testing or beside one another and are combined with one another, in order to form a linear array.

14 . The apparatus as claimed in claim 12 , wherein at least two magnet yokes of the combined receiving transducers have a common ferromagnetic connector.

15 . The apparatus as claimed in claim 14 , wherein at least two conductor loops forming independent receiving channels are arranged between the poles of at least one magnet yoke, each of the supply and return paths of said conductor loops running parallel.

16 . The method as claimed in claim 1 , wherein the objects are planar objects.

17 . A method for nondestructively testing objects made of a fiber composite material which is in at least single-layer form, the method comprising:
generating, via a transmitting transducer in the form of an EMUS transducer, an electromagnetic ultrasonic signal in the object by a conductive layer arranged on a surface of the object or in the object, detecting propagation of the ultrasonic signal in the object by a receiving transducer in the form of an EMUS transducer; determining, by an evaluation apparatus utilizing the ultrasonic signal detected by the at least one receiving transducer, a flaw in the form of a delamination, a porefield or other such two-dimensional inhomogeneities; wherein the transmitting transducer is used to produce a guided wave; and wherein the flaw is determined by virtue of a local phase velocity and/or a local wavelength of the received ultrasonic signal at a location of the receiving transducer being determined in the evaluation apparatus and used to determine the depth of the flaw.

Assignees

• Rosen Swiss Ag
• Rosen Ip Ag

Inventors

• Roelfes Tobias
• Krümpel Hanna

Classifications

• G01N2291/106

  one or more transducer arrays · CPC title

• G01N2291/0427

  Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever · CPC title

• G01N2291/0289

  Internal structure, e.g. defects, grain size, texture · CPC title

• G01N2291/0231

  Composite or layered materials · CPC title

• G01N29/2412

  using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]; (investigating the presence of flaws using eddy currents G01N27/90, magnetostrictive transducers B06B1/08, measuring magnetostrictive properties G01R33/18) · CPC title