AN ULTRASONIC TECHNIQUE FOR THE MEASUREMENT OF RESIDUAL STRESS

An ultrasonic shear wave technique to measure stress in metals is described. The technique utilizes a pulse-echo system operating at 7 MHz to measure changes in the time of travel of the ultrasonic shear wave to 1 part per million. Linear changes in the velocity of a shear wave occur with stress are dependent on the higher order elastic constants of the material. The linear change in velocity with stress allows the definition of a constant called the stress acoustic constant for the material. The amount of birefringence in a specimen is measured, and after accounting for the portion caused by anisotropy of the material, the remainder gives an accurate measure of the residual stress in the material. The amount of birefringence caused by anisotropy is a constant for specimens having the same nominal mechanical and thermal treatments. Measurements using the ultrasonic technique of simulated residual stress, introduced by bending of a 6-ft (1.8-m) section of A-36 steel I-beam, yield values in the vicinity of those measured using strain gage and O-ring techniques. Application of this technique to the measurement of other simple states of stress is suggested, along with the precautions to be observed for measuring stress. /Author/

  • Corporate Authors:

    American Society for Testing and Materials

    100 Barr Harbor Drive, P.O. Box C700
    West Conshohocken, PA  USA  19428-2957
  • Authors:
    • Noronha, P J
    • Wert, J J
  • Publication Date: 1975-3

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Filing Info

  • Accession Number: 00096136
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 2 1975 12:00AM