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J. Bär et alii, Frattura ed Integrità Strutturale, 34 (2015) 456-465; DOI: 10.3221/IGF-ESIS.34.51 465 Fig. 13 clearly shows the expected nonlinearity. All three curves show nearly the same run and are just shifted against each other. The shift can be explained by the problems to perform quantitative thermography measurements. The curves show that there is a defined correlation between the thermography and the peltier based heat flow measurement. This shows that different effects are measured with the two methods. To clarify these differences thermography measurements with defined reproducible coatings and combined heat flow measurements are projected. The lock in thermography as well as the peltier based heat flow measurement are interesting methods to gather additional information about the crack propagation behavior of metallic materials. The lock in thermography is cost intensive, difficult to quantify and complicated to synchronize with the other data obtain in crack propagation experiments. However, this method allows space resolved measurements and can distinguish between elastic and dissipated energies. The peltier based heat flow measurement is a simple, cost-efficient method delivering quantitative results and can be easily integrated into the control electronics. Unfortunately, only integral measurements are possible. Therefore, the combination of both methods is a promising way to gather useful information about the crack propagation behavior. A CKNOWLEDGEMENT his work was partly supported by The Perm Regional Government № С-26/619. R EFERENCES [1] Díaz, F.A., Yates, J.R., Patterson, E.A., Some improvements in the analysis of fatigue cracks using thermoelasticity, Int. J. of Fatigue, 26 (2004) 365-376. DOI: 10.1016/j.ijfatigue.2003.08.018. [2] Jones, R., Pitt, S., An experimental evaluation of crack face energy dissipation, Int. J. of Fatigue, 28 (2006) 1716-1724. DOI: 10.1016/j.ijfatigue.2006.01.009. [3] Bär, J., Seifert, S., Thermographic Investigation of Fatigue Crack Propagation in a High-Alloyed Steel, Advanced Materials Research, 891-892 (2014) 936 – 941, DOI:10.4028 /www.scientific.net/AMR.891-892.936. [4] Wagner, D., Ranc, N., Bathias, C., Paris, P.C., Fatigue crack initiation detection by an infrared thermography method, Fatigue Fract. Engng. Mater. Struct., 33 (2009) 12–21. DOI: 10.1111/j.1460-2695.2009.01410.x. [5] Bär, J., Seifert, S., Investigation of Energy Dissipation and Plastic Zone Size during Fatigue Crack Propagation in a High-Alloyed Steel, Procedia Materials Science, 3 (2014) 408 – 413, DOI:10.1016/j.mspro.2014.06.068. [6] Prokhorov, A., Vshivkov, A., Iziumova, A., Plehkov, O., Batsale, J. C., Development of the measurement system for determination of energy dissipation power at fatigue crack tip, QIRT 2014-147, http://qirt.gel.ulaval.ca/archives/qirt2014/QIRT%202014%20Papers/QIRT-2014-147.pdf [7] Vshivkov, A., Bär, J., Iziumova, A., Plekhov, O., Experimental study of heat dissipation at the crack tip during fatigue crack propagation, Frattura ed Integrità Strutturale, (2015), in press. [8] Bär, J., Volpp, T., Vollautomatische Durchführung von Ermüdungsrißausbreitungsexperimenten, Materials Testing, 43 (2001) 242-247. [9] Harwood, N., Cummings, W.M., MacKenzie, A.K., An Introduction in Thermoelastic Stress in: Thermoelastic Stress Analysis. In: Adam Harwood, N., Cummings, W.M. (Eds.). Adam Hilger, Bristol, (1991)1 – 34. [10] Brémond, P., New Developments in Thermo Elastic Stress Analysis by Infrared Thermography, IV Conferencia Panamericana de END, Buenos Aires (2007). [11] Sakagami, T., Kubo, S., Tamura, E. Nishimura, T., Identification of plastic-zone based on double frequency lock-in thermographic temperature measurement, In: ICF11, Italy, (2005). [12] Robinson, A.F., Dulieu-Barton, J.M., Quinn, S., Burguete, R.L., Paint coating characterization for thermoelastic stress analysis of metallic materials, Meas. Sci. Technol., 21 (2010) 085502, DOI:10.1088/0957-0233/21/8/085502. T