Quested, T E (2000) Finite element analysis of miniaturised electro thermo mechanical testing system. NPL Report. CMMT(A)291

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Abstract

The aim of this work was to provide an understanding of the temperature distributions of specimens heated within the miniaturised electro thermo mechanical testing (ETMT) system. Finite element (FE) modelling was used and its results compared with analytical solutions for simple cases.
Platinum strip was initially modelled. Temperature profiles along the strip were found as a function of current. The sensitivity of the temperature distribution to input parameters was explored; the effects of emissivity, coefficient of convective heat transfer and the free length of strip, and emissivity were all studied. The effect of the presence of a thennocouple was also investigated.
The temperature distribution between the water-cooled clamps was also modelled. The value of interfacial heat transfer between the clamps and bar was varied and the change in temperature distribution observed. This was compared to models in which material between the clamps was assumed to be held isothermally. This allowed an 'effective length' for a particular geometry and material to be found.
Studies of iron with an oxide scale were conducted to complement practical pyrometer measurements of temperature. Thermal profiles of cross-sections were determined including the temperature drop across the oxide. Different thicknesses, thermal conductivities and surface emissivity values of the oxide were modelled. These results were compared with analytical solutions.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMMT(A)291
Subjects:	Advanced Materials Advanced Materials > Materials Modelling Advanced Materials > Thermodynamics
Last Modified:	02 Feb 2018 13:17
URI:	http://eprintspublications.npl.co.uk/id/eprint/1634

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