Infrared Measurements of Heating and Cooling Emissions in Aluminium and Steel during Tensile and Cyclic Loading

In this paper,a new thermographic methodbased on the measurement of infrared emission(IR)from the surface of loaded body has been used tostudy the cooling and heating in aluminium andsteel specimens under tensile and cyclic loading.Atypical test procedure using infrared to measurethermographic changes near the crack tip and theimmediate surrounding area is described.In addi-tion,a procedure for determining the stress concen-tration near the crack tip is also presented.Resultsare given for thermoelastic cooling phenomenon ofmetals during the tensile process and IR coolingand IR heating emissions at the crack tip duringcyclic loading.Attention is drawn to the multiplephenomenon of IR cooling emission in the receivedsignal as the applied load range increases beyondthe elastic limit of both metals.A new applicationof the IR technique to the determination of the po-sition of crack tip during cyclic loading is also pres-ented.

Infrared Measurements of Heating and Cooling Emissions in Aluminium and Steel during Tensile and Cyclic Loading

In this paper,a new thermographic method based on the measurement of infrared emission(IR) from the surface of loaded body has been used to study the cooling and heating in aluminium 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 is described.In addi- tion,a procedure for determining the stress concen- tration near the crack tip is also presented.Results are given for thermoelastic cooling phenomenon of metals during the tensile process and IR cooling and IR heating emissions 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 both metals.A new application of the IR technique to the determination of the po- sition of crack tip during cyclic loading is also pres- ented.