The capacity to control thermal deformation is a key factor in piping systems, engines, energy plants, aircraft and space devices, to name a few. Thermal actuators, small electromechanical components that respond to temperature variations with extreme accuracy, are fundamental for the proper functioning of these systems. They perform tasks such as opening and closing valves, turning switches on and off, and other mechanical operations.
They are used in many applications in our daily life. It was generally held that a body could expand upon heating and contract on cooling only because of the material of which it is made. Until scientists found out that this property can be controlled through the geometrical design of its microstructure.
A study on this topic appeared in the British journal "Proceedings of the Royal Society A": the thermal deformation of a medium can be controlled by designing its geometrical microstructure, it does not depend exclusively on the materials used.
Therefore thermal expansion properties can be tailored to our needs.
For the results achieved, the work of Diego Misseroni of the University of Trento, Luigi Cabras of the University of Brescia, and Michele Brun of the University of Cagliari was featured on the journal cover, for an article describing the experiments conducted at the University of Trento and demonstrating that thermal deformation can be controlled.
The results of this joint research work open new horizons for the development of new materials that could be used in areas in which thermal deformation is crucial and must therefore be efficiently controlled or minimized (for mechanical, optical and electronic components, and in construction), or where thermal deformation is a fundamental property (thermal actuators in general and, more specifically, high performance actuators integrating electrical circuits with opto-mechanical devices).
All authors contributed equally to this study and to the writing of the manuscript. In particular, Diego Misseroni (researcher at the University of Trento–Department of Civil, Environmental and Mechanical Engineering) had a leading role in the experimental part, Luigi Cabras (postdoc at the University of Brescia–Department of Mechanical and Industrial Engineering) in the numerical part, and Michele Brun (professor of the University of Cagliari–Department of Mechanical, Chemical and Material Engineering) in the analytical part.
About the article
"Micro-structured medium with large isotropic negative thermal expansion", which also includes a numerical and experimental demonstration, was published on 18 December 2019.
The authors of the study are: Luigi Cabras, Michele Brun and Diego Misseroni.
Cover image: ©Diego Misseroni