Acoustic Emission Fatigue Analyzer.
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 25, 1977
- Accession Number
- ADD003994
Entities
People
- John M. Carlyle
- William R. Scott
Organizations
- United States Department of the Navy