Accession Number : ADD003994

Title :   Acoustic Emission Fatigue Analyzer.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Scott,William R ; Carlyle,John M

Report Date : 25 Feb 1977

Pagination or Media Count : 21

Abstract : A device for acquiring and displaying acoustic emission fatigue data so as to facilitate the interpretation of dynamic micromechanical failure processes in materials is described. The load on a specimen under cyclic loading is monitored by a load cell whose output is sent to a cycle counter. The specimen is also monitored by a transducer which senses acoustic emissions. The signal produced by the transducer passes through a preamplifier, filter, amplifier and threshold detector to a pulse generator whose output is connected to the intensity modulation input of an oscilloscope or other cartesian coordinate arraying device. The load cell output is also connected to the vertical deflection input of the oscilloscope. The counter output is connected to the horizontal deflection input of the oscilloscope. Every time that the transducer detects an acoustic emission event, that event is represented on the oscilloscope in a 2-dimensional cartesian coordinate system as a dot whose ordinate corresponds to the instantaneous load (derived from the load cell) and whose abscissa corresponds to the number of elapsed fatigue cycles (derived from the counter) at the time the event occurred, resulting in the simultaneous recording of the relationship between sample load, acoustic emission rate and number of fatigue cycles.

Descriptors :   *Patent applications, *Acoustic emissions, *Fatigue tests(Mechanics), Display systems, Transducers, Preamplifiers, Oscilloscopes, Cyclic tests, Load cells

Subject Categories : Test Facilities, Equipment and Methods
      Acoustics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE