Other Reports

Infrared Measurements of Heating and Cooling Emissions at a Crack Tip During Tensile and Cyclic Loading

  • 01
  • Feb
  • 1988
AUTHOR: Y. Huang, G. E. Hicho, R. J. Fields
OFFICE: RPD
REPORT NUMBER: FRA/ORD-88/11
SUBJECT: Rail and Infrastructure Integrity
KEYWORDS: Aluminum, Steel, Stress Concentration, Thermoelastic Effects
ABSTRACT: A new thermographic method based on the measurement of infrared (IR) emission from the surface of a loaded body was used to study the cooling and heating in aluminum and steel specimens under tensile and cyclic loading. A typical test procedure using infrared to measure thermographic changes near the crack tip and the immediate surrounding area are described. Results are given for thermoelastic cooling phenomenon of metals during tensile process and IR cooling and IR heating emission at the crack tip during cyclic loading. Attention is drawn to the multiple phenomenon of IR cooling emission in the received signal as the applied load range increases beyond the elastic limit of the metals. A new application of the IR technique to the determination of the position of crack tip during cyclic loading is also presented.

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