NON-DESTRUCTIVE ULTRASOUND TESTING OF STRUCTURES MADE OF COMPOSITE MATERIAL

• US 20150160166A1
• Filed: 06/17/2013
• Published: 06/11/2015
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV), European Aeronautic Defence and Space Company EADS NV
• Original Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV), European Aeronautic Defence and Space Company EADS NV
• Inventors: Pages, Marion, Metayer, Patrick
• Granted Patent: US 9,632,063 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 2291/0289 Internal structure, e.g. defects, grain size, texture
• CPC Class Codes: G01N 2291/045 External reflections, e.g. on reflectors
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/24 Probes transducers for acoustic waves B06B, G10K; for measuring G01H
• CPC Class Codes: G01N 29/44 Processing the detected response signal , e.g. electronic circuits specially adapted therefor digital signal processing per se G06F17/00
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values

Abstract

The invention relates to a diagnostic apparatus 1 for detecting delamination in the thickness of a panel of laminated composite. The diagnostic apparatus can be used to inspect a panel having a non-constant thickness along its length.

The diagnostic apparatus comprises an ultrasonic probe 30 intended to be brought into contact with the front face of the panel to be inspected, an electronic device 40 for controlling the emission and reception of ultrasonic pulses 51 by the ultrasonic probe 30, and a display device 41 having, notably, indicators showing the presence or absence of delamination in the panel.

Claims

1. A diagnostic apparatus (1) for detecting delamination (14) in the thickness of a laminated composite panel (10), which apparatus comprises an ultrasonic probe (30) intended, in use, to be brought into contact with a face (11) of said panel and moved over said face, said probe (30) comprising a plurality of elementary transducers (36a, 36b, . . . , 36n) and an electronic device (40) connected to each of said transducers to control the emission and reception of ultrasonic pulses (51) by said probe (30) by the activation of at least one elementary transducer (36a, 36b, . . . , 36n), the apparatus (1) further comprising a display device (41) having at least a first indicator which can be activated by the electronic device (40) when the latter detects the presence of delamination in the panel, said electronic device (40) being configured to calculate the value of an indicator of the coupling of said probe (30) with said face (11), and to switch, if the value of the coupling indicator is equal to a predetermined value, from a coupling mode to a scanning mode, the scanning mode being such that, during emission, the electronic device (40) transmits the same pulsed signal successively to the elementary transducers (36a, 36b, . . . , 36n) according to a predetermined activation sequence for the elementary transducers, and such that, during reception, the electronic device (40) analyzes the signals received by the elementary transducers so as to detect delamination (14) in a predetermined depth range of the thickness of said panel (10).

2. The diagnostic apparatus (1) as claimed in claim 1, wherein, in the coupling mode, during transmission, the electronic device (40) transmits the same pulse signal simultaneously to each of the elementary transducers (36a, 36b, . . . , 36n), and, during reception, the electronic device (40) analyzes the signals received by the elementary transducers in order to calculate the value of the coupling indicator.

3. The diagnostic apparatus (20) as claimed in claim 1, wherein the display device (41) further comprises a second indicator (413) that can be activated by the electronic device (40) when this device is switched to scanning mode.

4. A method for detecting delamination (14) in the thickness of a panel of laminated composite (10), said panel (10) having a first face, called the front face (11), said method being applied by means of the diagnostic apparatus as claimed in claim 1, wherein the method includes the following successive steps:

a) comparison of a value of the coupling indicator with a predetermined value;

b) for an activation sequence of the elementary transducers, and if the value of the coupling indicator is equal to said predetermined value;

1) emission of an ultrasonic pulse (51) by each of the plurality of elementary transducers (36a, 36b, . . . , 36n) toward the panel (10);

2) reception by each of the elementary transducers (36a, 36b, . . . , 36n) of a pulse reflected by the panel (10);

3) reconstitution, by the electronic device (40) of a scanning signal (33b), based on the plurality of reflected pulses received;

c) activation of an indicator of the means of presenting the information (411) indicative of the presence of delamination (14) in the thickness of said panel (10) when the scanning signal (33b) has a peak (34b) having an amplitude above a predefined threshold (39), representing a time of flight of a received pulse whose duration is;

strictly greater than that of a time of flight of a received pulse corresponding to the pulse reflected by said front face (11), and

strictly less than that of a time of flight of a received pulse which would correspond to the pulse reflected by an element located at a distance e_max from said front face (11).

5. The method as claimed in claim 4, wherein the value of the coupling indicator is equal to the predetermined value when:

A) the result of the subtraction between the time of flight of a first pulse received by an elementary transducer when the probe (30) is in contact with the front face (11) of the panel and the time of flight of a first pulse received by the same elementary transducer when the probe (30) is not in contact with said front face (11) is below a predetermined threshold,

B) the rate of deformation of a signal reflected by said front face (11) and received by the same elementary transducer when the probe is in contact with said front face (11) is greater than a predetermined rate of deformation; and

C) occurrences A and B are valid for a number of elementary transducers greater than a predetermined number.

6. The method as claimed in claim 4, wherein the distance emax is less than half of the known thickness of the panel (10).

7. The method as claimed in claim 4, wherein the check of the correctness of coupling is performed at regular time intervals.