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Title: Acoustic emission linear pulse holography

Abstract

This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

Inventors:
; ;
Publication Date:
OSTI Identifier:
6672756
Alternate Identifier(s):
OSTI ID: 6672756; Legacy ID: DE84014519
Application Number:
ON: DE84014519
Assignee:
Dept. of Energy EDB-84-140915
DOE Contract Number:
AC06-76RL01830
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; ACOUSTIC EMISSION TESTING; CRACK PROPAGATION; ACOUSTIC MONITORING; HOLOGRAPHY; INSPECTION; INVENTIONS; PIEZOELECTRICITY; ACOUSTIC TESTING; ELECTRICITY; MATERIALS TESTING; MONITORING; NONDESTRUCTIVE TESTING; TESTING 440300* -- Miscellaneous Instruments-- (-1989)

Citation Formats

Collins, H.D., Busse, L.J., and Lemon, D.K. Acoustic emission linear pulse holography. United States: N. p., 1983. Web.
Collins, H.D., Busse, L.J., & Lemon, D.K. Acoustic emission linear pulse holography. United States.
Collins, H.D., Busse, L.J., and Lemon, D.K. Tue . "Acoustic emission linear pulse holography". United States. doi:.
@article{osti_6672756,
title = {Acoustic emission linear pulse holography},
author = {Collins, H.D. and Busse, L.J. and Lemon, D.K.},
abstractNote = {This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 25 00:00:00 EDT 1983},
month = {Tue Oct 25 00:00:00 EDT 1983}
}
  • Defects in a structure are imaged as they propagate, using their emitted acoustic energy as a monitored source. Short bursts of acoustic energy propagate through the structure to a discrete element receiver array. A reference timing transducer located between the array and the inspection zone initiates a series of time-of-flight measurements. A resulting series of time-of-flight measurements are then treated as aperture data and are transferred to a computer for reconstruction of a synthetic linear holographic image. The images can be displayed and stored as a record of defect growth.
  • Defects in a structure are imaged as they propagate, using their emitted acoustic energy as a monitored source. Short bursts of acoustic energy propagate through the structure to a discrete element receiver array. A reference timing transducer located between the array and the inspection zone initiates a series of time-of-flight measurements. A resulting series of time-of-flight measurements are then treated as aperture data and are transferred to a computer for reconstruction of a synthetic linear holographic image. The images can be displayed and stored as a record of defect growth.
  • This paper describes Acoustic Emission Linear Pulse Holography which combines the advantages of linear imaging and acoustic emission into a single NDE inspection system. This unique system produces a chronological linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. Conventional linear holographic imaging uses an ultrasonic transducer to transmit energy into the volume being imaged. When the crack or defect reflects that energy, the crack acts as a new source of acoustic waves. To formulate an image of that source, a receiving transducer is scanned over the volume of interest and the phase ofmore » the received signals is measured at successive points on the scan. The innovation proposed here is the utilization of the crack generated acoustic emission as the acoustic source and generation of a line image of the crack as it grows. A thirty-two point sampling array is used to construct phase-only linear holograms of simulated acoustic emission sources on large metal plates. The phases are calculated using the pulse time-of-flight (TOF) times from the reference transducer to the array of receivers. Computer reconstruction of the image is accomplished using a one-dimensional FFT algorithm (i.e., backward wave). Experimental results are shown which graphically illustrate the unique acoustic emission images of a single point and a linear crack in a 100 mm x 1220 mm x 1220 mm aluminum plate.« less
  • This patent describes a borehole seismic impulse source transducer comprising: an elastic outer housing and an elastic, electrically insulating inner housing each attached to and extending from a downhole end member to an uphole end member; hydraulic fluid filling space between the inner and the outer housing; an enclosed chamber formed in the inner housing, the chamber divided into an upper volume and a lower volume by an insulator having a small aperture channel therein, whereby the upper and lower volume of the chamber are in fluid communication, the chamber completely filled with electrolyte fluid; a first and second electrodemore » extending into the upper volume and the lower volume, respectively, and in spaced relation from one another; means for supplying high voltage across the electrodes whereby an arc discharge is produced through and in the vicinity of the aperture channel; means for intermittent venting of a gas build up produced as a result of a number of the arc discharges in the electrolyte fluid, the gas venting means having a means for sensing the gas build up with the chamber; and means for increasing pressure and volume of the hydraulic fluid for expanding the outer housing prior to the arc discharge and after the source transducer is positioned within a borehole.« less
  • An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively,more » be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.« less