JOURNAL OF SOUND AND VIBRATION Journal of Sound and Vibration 308 (2007) 514–525 Thermal vibrational analysis for simply supported beam and clamped beam Jurij Avsec , Maks Oblak Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, 2000 Maribor, P.O. Box 224, Slovenia Accepted 4 April 2007 The peer review of this article was organised by the Guest Editor Available online 22 May 2007 Abstract The presented paper shows how the temperature field in beams has impact on vibrations of beams. Due to th high possibletemperaturevariationsin beams we have developed themathematical model wherefundamental thermomechanical properties of state are functions of temperature such as modulus of elasticity, Poisson numb expansion coefficient, shear modulus and some other important thermodynamic properties of state. The detaile shows, that also small changes of temperature cause significant changes of natural frequencies for beams. The between our analytical model and experimental data shows good agreement. In the presented paper it is possi the first time in scientific literature the application of the combination of statistical thermodynamics and the theory of vibration at the same time. r 2007 Elsevier Ltd. All rights reserved. 1. Introduction Mechanics is a very important scientific discipline, developing at an ever increasing pace. Nonlinea of vibrations represents one of the most important areas [1] in modern science. From theoretical view nonlinear mechanics constitutes an extremely complex mathematical problem.Particularly complex are the models of nonlinear vibrations in the area of chaos and bifurcations. In terms of the engineering appr theory of vibrations means a basic method in technical systems design. In the majority of cases, the temperature changes are ignored, yet many times they need to be taken into consideration. In such analyses of the above indicated problems become very complex. Mechanicalmachines very often operate under diverse temperature conditions. In internalcombustion engines, rocket systems, movement of the satellites, etc. the conditions are particularly temperature Thermodynamic effects are frequently ignored in research, which may yield totally incorrect results. [2–6] shows that even the slightest temperature change leads to huge alteration of the clamped bea properties. Contrary as in papers [1,2], the impactin the presentpaper is notneglected of a change in thermodynamic properties, which have to be taken into consideration at major temperature changes ARTICLE IN PRESS www.elsevier.com/locate/jsvi 0022-460X/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jsv.2007.04.002 Corresponding author. E-mail address: jurij.avsec@uni-mb.si (J. Avsec).