Method and apparatus for detecting and determining event characteristics with reduced data collection

• US 20040025091A1
• Filed: 07/30/2002
• Published: 02/05/2004
• Est. Priority Date: 07/30/2002
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Totman, Peter D., Macon, David J., Everton, Randy L., Egget, Mark R.
• Granted Patent: US 7,240,564 B2
• Time in Patent Office: Days
• US Class Current: 714/47
• CPC Class Codes: G01N 2203/0066 Propagation of crack
• CPC Class Codes: G01N 2203/0623 using piezoelectric gauges
• CPC Class Codes: G01N 3/066 with electrical indicating or recording means

Abstract

A method and apparatus for detecting and determining event characteristics such as, for example, the material failure of a component, in a manner which significantly reduces the amount of data collected. A sensor array, including a plurality of individual sensor elements, is coupled to a programmable logic device (PLD) configured to operate in a passive state and an active state. A triggering event is established such that the PLD records information only upon detection of the occurrence of the triggering event which causes a change of state within one or more of the plurality of sensor elements. Upon the occurrence of the triggering event, the change in state of the one or more sensor elements causes the PLD to record in memory which sensor element detected the event and at what time the event was detected. The PLD may be coupled with a computer for subsequent downloading and analysis of the acquired data.

Claims

1. An apparatus for monitoring and detecting event characteristics comprising:

a sensor array including a plurality of sensor elements; and

a programmable logic device (PLD) operatively coupled to the plurality of sensor elements, the PLD being configured operate in a default passive state and an event triggered active state.

2. The apparatus of claim 1, wherein a change of state occurring in any of the plurality of sensors causes the PLD to switch from the default passive state to the event triggered active state.

3. The apparatus of claim 2, wherein the PLD includes a memory component having a plurality of memory locations, each of the plurality of memory locations being associated with an individual one of the plurality of sensor elements.

4. The apparatus of claim 3, wherein the PLD is configured such that a change in state of one of the plurality of sensor elements is detected by the PLD and data associated with the change of state is stored in the associated memory location of the one of the plurality of sensor elements.

5. The apparatus of claim 4, wherein the data associated with the change of state includes the time at which the change of state occurred.

6. The apparatus of claim 5, wherein the PLD is configured to be operatively coupled with a computer.

7. The apparatus of claim 2, wherein the PLD includes a field programmable gate array (FPGA) device.

8. The apparatus of claim 7, wherein the plurality of sensor elements include a plurality of conductors configured to break upon the detection of a predefined event to indicate the change of state.

9. The apparatus of claim 8, wherein the plurality of sensor elements are disposed on a thin sheet of dielectric material.

10. The apparatus of claim 9, wherein the thin sheet of material includes a polyimide material.

11. The apparatus of claim 9, wherein the thin sheet of material exhibits a thickness of approximately 0.001 inches at a first portion thereof which is distally located relative to the FPGA device.

12. The apparatus of claim 11, wherein the thin sheet of material tapers in thickness from the first portion to a second portion which is adjacent the FPGA device.

13. The apparatus of claim 12, wherein the thin sheet of material exhibits a thickness of approximately 0.003 inches in the second portion.

14. The apparatus of claim 9, wherein the plurality of conductors are disposed on the thin sheet of material in a substantially parallel manner.

15. The apparatus of claim 14, wherein the plurality of conductors exhibit substantially equal spacing from one another.

16. The apparatus of claim 15, wherein the plurality of conductors are spaced approximately 0.050 inches from one another.

17. The apparatus of claim 1, wherein the PLD includes a simple programmable logic device.

18. The apparatus of claim 1, wherein the PLD includes a complex programmable logic device.

19. The apparatus of claim 1, wherein the plurality of sensors are photosensitive.

20. The apparatus of claim 18, further comprising a light source configured and positioned to provide light to the plurality of sensors.

21. The apparatus of claim 1, wherein the plurality of sensors includes a plurality of magnetic sensors.

22. The apparatus of claim 1, wherein the plurality of sensors includes a plurality of piezoelectric transducers.

23. The apparatus of claim 1, wherein the PLD includes a timing device having a resolution of at least approximately 10⁻

6 seconds.

24. A system for determining fracture characteristics of an adhesive material comprising:

a test specimen including a first member and a second member coupled together with the adhesive material;

a load applying apparatus including at least one load applying member configured to apply a load to the test specimen such that the first and second members are loaded in a cantilevered manner;

a plurality of break-wire conductors coupled the test specimen; and

a programmable logic device (PLD) operatively coupled to the plurality break-wire conductors configured operate in a default passive state and an event triggered active state such that upon the breaking of one of any of the plurality of break-wire conductors the PLD switches from the default passive state to the event trigger active state, wherein the PLD while in active state is configured to record information in memory regarding which of the break-wire conductors broke and at what time.

25. The system of claim 24, wherein the plurality of break-wire conductors include copper conductors.

26. The system of claim 25, wherein the plurality of break-wire conductors are disposed on a thin dielectric sheet and wherein the thin sheet is adhered to the test specimen such that the plurality of break-wire conductors traverse a bond line formed by the adhesive material between the first member and the second member.

27. The system of claim 26, wherein the plurality of conductors are arranged to be substantially perpendicular to the bond line.

28. The system of claim 26, wherein the thin dielectric sheet includes a polyimide material.

29. The system of claim 26, wherein a portion of the thin dielectric sheet is coupled to the test specimen with an adhesive.

30. The system of claim 29, wherein the portion of the thin dielectric sheet coupled to the test specimen exhibits a material thickness of approximately 0.001 inches.

31. The system of claim 30, wherein the thin sheet exhibits a thickness of approximately 0.003 inches in a portion thereof which is located adjacent the PLD.

32. The system of claim 26, wherein the plurality of conductors are arranged in a substantially parallel manner.

33. The system of claim 32, wherein the plurality of conductors exhibits a spacing of approximately 0.050 inches from one another.

34. The system of claim 25, wherein the PLD includes a field-programmable gate array (FPGA).

35. The system of claim 25, wherein the PLD is configured to be operatively coupled to a computer.

36. The system of claim 24, wherein the PLD includes a timing mechanism which has a resolution of at least approximately 10⁻

6 seconds.

37. A method of monitoring an event, the method comprising:

establishing an event trigger;

providing a plurality of sensor elements, each configured to individually detect the event trigger;

providing a programmable logic device (PLD) and configuring the PLD to operated in a default passive state and an event triggered active state; and

upon a detection of the event trigger, storing data associated with detection of the event trigger including which of the plurality sensor elements detected the event trigger and at what time the event trigger was detected thereby.

38. The method according to claim 37, wherein storing the time the event trigger was detected includes storing the time at a resolution of at least approximately 10⁻

6 seconds.

39. The method according to claim 37, wherein providing a plurality of sensor elements includes providing a plurality of break-wire conductors and configuring the break-wire conductors to individually break upon the detection of the event trigger thereby.

40. The method according to claim 37, further comprising establishing the event trigger as a change in pressure.

41. The method according to claim 37, further comprising establishing the event trigger as a change in a magnetic field.

42. The method according to claim 37, further comprising establishing the event trigger as a change in a light field.

43. The method according to claim 37, further comprising downloading the stored data to a computer.

44. The method according to claim 43, further comprising making a time map representative of the downloaded data.

45. A monitoring apparatus comprising:

a plurality of sensors configured to detect a specified event;

a programmable logic device (PLD) configured to operate in a passive state and an active state such that, when in the passive state the PLD stores no data and, when in the active state, the PLD stores in associated memory discrete and discriminate data associated with selective ones of the plurality of sensors.

46. The apparatus of claim 45, wherein the PLD switches from the passive state to the active state upon detection of the specified event by at least one of the plurality of sensors.

47. The apparatus of claim 46, wherein the PLD includes a field-programable gate array (FPGA).

48. The apparatus of claim 45, wherein the PLD is configured to be operatively coupled with a computer.