An Optical Gage for Strain/Displacement Measurement at High Temperature Near Fatigue Crack Tips.

Abstract

The interferometric strain/displacement gage (ISDG) relates the motion of fringe patterns generated by a laser beam impinging upon closely-spaced indentations to local surface deformation. The purpose of this research was to extend the technique to real-time crack tip opening displacement (CTOD) and biaxial strain measurements on superalloys at high temperatures. The indentations must remain reflective at temperature; they can be protected with a coating. A coating was developed to protect Incolloy 901 for several hours at 650 C. IN-100 will remain reflective if it is preoxidized in an rf furnace, but an electroplated chromium and vapor-plated platinum coating produces better fringe patterns.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1977
Accession Number
ADA057664

Entities

People

  • Donald R. Martin
  • William N. Sharpe Jr.

Organizations

  • Michigan State University

Tags

Communities of Interest

  • Advanced Electronics
  • Sensors

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Coatings
  • Crack Tips
  • Detectors
  • Engineering
  • Frequency
  • Frequency Response
  • High Temperature
  • Laser Beams
  • Materials
  • Materials Laboratories
  • Measurement
  • Metals
  • Resistance
  • Sheet Metal
  • Waveforms

Fields of Study

  • Physics

Readers

  • Materials Science (Mechanical Engineering).
  • Radar Systems Engineering.
  • Surface Engineering/Surface Coating Technology.

Technology Areas

  • Directed Energy
  • Space