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ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
THERMAL DIFFUSIVITY IDENTIFICATION OF NICKEL-TITANIUM SMA USING A PERIODIC TEMPERATURE FIELD
Submission Author:
José Ricardo Ferreira Oliveira , MG
Co-Authors:
José Ricardo Ferreira Oliveira, Luiz Roberto Rocha de Lucena, Romulo Pierre Batista dos Reis, Carlos Jose de Araujo, Celso Rosendo Bezerra Filho
Presenter: José Ricardo Ferreira Oliveira
doi://10.26678/ABCM.ENCIT2018.CIT18-0354
Abstract
Shape Memory Alloy (SMA) is a kind of metalic materials that changes his mechanical properties when induced by temperature (shape memory effect) or strain (superelastic effect). These characteristics make SMA´s have applications in several projects in areas such as control and automation, automotive, aeroespace and biomedical. In these applications, the phenomenea linked to heat transfer process play a fundamental role. Thermal diffusivity is a very important thermophysical property in the analysis of thermal energy diffusion problems. This work had the purpose of determining this property in a Nickel-Titanium SMA using a periodic heat field. For this, an experimental device was build whose principle of operation based on the Angstrom´s Method, which makes use of a periodic heat flux in the sample, generating in this a periodic heat flow. Therocouples were installed in the sample to capture the temperature signals generated by the periodic heat flow. Amplitude and phase of these signals were obtained by graphical analysis software. The thermocouple closest to the heat source was adopted as reference, whereas the ratio of amplitudes and the phase between the signals recorded by the others thermocouples in relation to that thermocouple were calculated. These results were used in mathematical models to identify the thermal diffusivity, whose value found, when compared with the values available in the literature, obtained a good agreement, considering the range of uncertainty adopted.
Keywords
Thermal Diffusivity, thermophysical properties, Shape Memory Alloys, Experimental device, Angstrom's Method
