Termodynamics of no-tension materials

After a brief review of the thermodynamics 0f isotropic elastic materials, this paper presents a constitutive equation for no-tension materials in the presence of thermal expansion that accounts for the temperaturedependence of their material's constants. Specifically, under the hypothesis of infinitesimal strains, an explicit expression is if given for free energy from which the intemal energy, entropy and stress are obtained. Then, the basic equations of the thermo-mechanical equilibrium of a no+tension solid are presented, and we observe that, under the further hypothesis of an infinitesimal strain rate, thermo-mechanical uncoupling occurs. Finally, a study is performed of a circular ring made of a no-tension material subjected to a plane stress under the action of both two uniform radialpressures exertedon the inner and outer boundary and a temperature distribution varying linearly with the radius; all material constants are assumed temperature-independent, except for Young's modulus, which depends linearly on thetemperature. The stress field, displacement field, fractures, free energy and entropy are explicitly calculated and compared with these same quantities for a circular ring made of a linear elastic material