ACOUSTIC EMISSION

SEVERAL APPLICATIONS OF ACOUSTIC EMISSION TECHNIQUES ARE DISCUSSED FROM A TECHNICAL STANDPOINT, AMONG THEM BEING FLAW DETECTION, PREDICTION OF SUSCEPTIBILITY TO STRESS CORROSION CRACKING AND HYDROGEN EMBRITTLEMENT, MEASUREMENT OF COATING THICKNESS, AND DETECTION OF HIGH-TEMPERATURE FAILURE. FUTURE USES MAY BE DETERMINATION OF FAILURE PROBABILITY AND DETECTION OF CRACKS BEFORE THEY REACH A CRITICAL SIZE. THE TECHNIQUE IS BASED ON ANALYSIS OF IMPULSIVELY GENERATED SMALL-AMPLITUDE ELASTIC STRESS WAVES CREATED BY DEFORMATIONS IN A MATERIAL. THE RAPID RELEASE OF KINETIC ENERGY FROM THE DEFORMATION MECHANISM PROPAGATES ELASTIC WAVES FROM THE SOURCE, AND THESE ARE DETECTED AS SMALL DISPLACEMENTS ON THE SURFACE OF THE SPECIMEN. THE EMISSIONS INDICATE THE ONSET AND CONTINUATION OF DEFORMATION AND MAY BE USED TO LOCATE THE SOURCE OF DEFORMATION THROUGH TRIANGULATION. THE PATTERN OF EMISSION IS DETERMINED BY THE TIME DISTRIBUTION OF THE IMPULSIVE DEFORMATIONS, AND CONSEQUENTLY THE STUDY OF LOCAL DEFECTS CAN BE CONDUCTED WITHOUT PRIOR KNOWLEDGE OF THEIR EXISTANCE OR LOCATION. IN ADDITION, EMISSION DATA DESCRIBE THE VOLUMETRIC DEFORMATION PROCESSES NOT ADEQUATELY AVAILABLE FROM SURFACE PHENOMENA, THUS PERMITTING A MORE COMPREHENSIVE INSIGHT INTO SUCH DEFORMATION PROCESSES AS PLASTIC FLOW, FRACTURE, AND PHASE TRANSFORMATIONS.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/07469179
• Supplemental Notes:
  • Vol 22, No 5, PP 20-24, 7 FIG
• Authors:
  • Dunegan, H L
  • Tetelman, A S
• Publication Date: 1971-5

Media Info

• Serial:
  • Research & Development
  • ISSN: 0746-9179

Subject/Index Terms

• TRT Terms: Acoustics; Cracking; Defects; Deformation; Detection and identification; Detectors; Embrittlement; Failure; Hydrogen; Nondestructive tests; Stress corrosion; Stresses
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00217128
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 2 1971 12:00AM