Location

La Jolla, CA

Start Date

1-1-1983 12:00 AM

Description

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 of the received signals is measured at successive points on the scan.

The innovation proposed in this paper 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 × 1220 mm × 1220 mm aluminum plate.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

2A

Chapter

Section 9: Acoustic Emission

Pages

503-516

DOI

10.1007/978-1-4613-3706-5_30

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Acoustic Emission Linear Pulse Holography

La Jolla, CA

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 of the received signals is measured at successive points on the scan.

The innovation proposed in this paper 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 × 1220 mm × 1220 mm aluminum plate.