Method and device for monitoring an aircraft structure

• US 20110112775A1
• Filed: 04/14/2006
• Published: 05/12/2011
• Est. Priority Date: 04/18/2005
• Status: Abandoned Application

• Current Assignee: European Aeronautic Defence and Space Company EADS NV
• Original Assignee: European Aeronautic Defence and Space Company EADS NV
• Inventors: Bramban, Didier Honoré
• Application Number:
  US11/918,810
• Publication Number:
  US 20110112775A1
• Time in Patent Office: Days
• US Class Current: 702/56
• CPC Class Codes: G01B 17/04 for measuring the deformation in a solid, e.g. by vibrating string
• CPC Class Codes: G01H 1/12 of longitudinal or not specified vibrations
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 29/045 by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks measuring resonant frequency G01H13/00; measuring strength properties by application of mechanical stress G01N3/00
• CPC Class Codes: G01N 29/2475 Embedded probes, i.e. probes incorporated in objects to be inspected
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005

Abstract

The invention relates to servicing an aircraft. For this purpose said aircraft is provided with a permanently monitoring device comprising piezo-electric sensors. The inventive method consists in continuously recording signals transmitted by said sensors and in subsequently calculating a fatigue to which the aircraft critical parts are exposed, thereby making it possible to better monitoring said critical parts. Said invention makes it possible to reduce the aircraft servicing costs.

Claims

1. A method of monitoring a structure of an aircraft wherein

effects of impacts, stress or agreeing aging on the-structure are measured by a monitoring system having a central processing unit,

wherein the method comprises;

positioning piezoelectric sensors are placed on parts of the-structure that are to be monitored;

reading signals delivered by the sensors; and

processing the signals in the central processing unit during a useful service life of the aircraft, on the ground and in flight.

wherein the signals are a resulting from the a presence of an acoustic wave in the structure at a position of the sensors,

2. The method according to claim 1, wherein reading signals further comprises:

validating an operation of a set formed by sensors connected to the central processing unit.

3. The method according to claim 1, further comprising:

coupling the monitoring system to a constant, uninterruptible electrical power supply; and

monitoring the electrical power supply.

4. The method according to claim 1, further comprising:

testing a state of a communications bus between sensors and the central processing unit is during reading.

5. The method according to claim 1, wherein reading signals comprises measuring, at least one characteristics of a signal, wherein the at least one characteristic is selected from the group consisting of:

concerned sensor references,

a date of a measured, acoustic event,

a frequency of a measured acoustic wave,

a number of half waves of a signal for which the value is above a threshold,

a duration of a burst of half waves of the signal for which the value is above a threshold,

a maximum value of the signal,

a minimum value of the signal,

a build-up time of the signal,

a frequency spectrum of the signal,

a delay of the signal, and combinations thereof.

6. The method according to claim 1, further comprising one or more of the following operations:

verifying the presence of the detectors;

checking with a watchdog function to ascertain that the processing unit is not operating in a loop;

monitoring four zones of the aircraft with 24 sensors per zone, these zones being a radome of the aircraft, leading edges of wings of this aircraft and a tail unit of this aircraft;

measuring the signal for about 100 microseconds at each acoustic event;

measuring the signal situated in a frequency band ranging from 20 kHz to 2 MHz;

defining a threshold beyond which it is decided to measure a signal, this threshold being different depending on whether the aircraft is in flight or on the ground;

storing the signal in a fast buffer memory to record the events whose duration is shorter than a time of storage in an EEPROM type memory; and

determining an upper signal threshold and, for signals above this threshold, producing an alarm signal.

7. A device for monitoring a structure and of aircraft comprising:

a detection device positioned on an aircraft, wherein the detection device is operable to detect, by acoustic measurement the effects of impacts, stress, aging, and combinations thereof, of the-structure; and

a security device for the operating security of the detection device.

8. The device according to claim 7, wherein the device further comprises means for monitoring an analog signal produced by the detection device.

9. A monitoring apparatus for monitoring a structure of an aircraft wherein effects of impacts, stress or aging on the structure are measured, the monitoring apparatus comprising:

a plurality of piezoelectric sensors positioned on parts of the structure that are to be monitored; and

an electronic assembly powered by an electrical power supply, wherein the electronic assembly includes;

a signal processing unit having at least one of an analog/digital convertor, a multiplexer, a field-programmable gate array circuit, and a digital signal processor, and

a diagnostic tool comprising a central processing unit and a large-capacity memory,

wherein the monitoring apparatus monitors signals resulting from the presence of an acoustic wave in the structure at the position of the sensors during a useful service life of the aircraft, both on ground and in flight.

10. An electronic device for monitoring a structure of an aircraft, the device comprising:

acoustic sensors coupled to structural portions of the aircraft to sense acoustical signals;

a recording system operably coupled to the sensors to receive and record the acoustical signals in real time, wherein the sensed acoustical signals arise from impact to, stress, or flexure of portions of the aircraft during a useful life of the aircraft, both on ground and in flight.

11. The electronic device of claim 10, wherein the electronic device is carried onboard the aircraft throughout the useful life of the aircraft.

12. The electronic device of claim 10, wherein the electronic device is powered by a continuous and uninterruptible electrical power supply.

13. The electronic device of claim 10, wherein the acoustic sensors comprise piezoelectric sensors.

14. The electronic device of claim 10, wherein the acoustic sensors are coupled to portions of the aircraft selected from the group consisting of a radome, leading edges of wings, a tail unit, and combinations thereof.