Volume no :14, Issue no: 2, November (2015)

CONSTITUTIVE THEORIES FOR INTERNAL POLAR THERMOELASTIC SOLID CONTINUA

Author's: K. S. Surana, M. Powell and J. N. Reddy
Pages: [89] - [150]
Received Date: September 29, 2015
Submitted by:
DOI: http://dx.doi.org/10.18642/jpamaa_7100121545

Abstract

In recent papers [1, 2] the authors presented an internal polar continuum theory for solid continua (under the name a polar continuum theory) in which varying internal rotations and conjugate moments between neighboring material points that exist in all deforming homogeneous and isotropic solid continua were incorporated in the derivations of the conservation and balance laws. It was shown that this theory leads to a more complete thermodynamic framework as it incorporates the additional physics due to varying internal rotations that is completely neglected in the currently used thermodynamic framework. The currently used thermodynamic framework for solid continua is a subset of the internal polar continuum theory presented in [1, 2].

Just as in non-internal polar thermoelastic solid continua, in internal polar thermoelastic solid continua also (both compressible and incompressible), the mechanical deformation is reversible, hence in such continua there is no mechanism of conversion of mechanical energy into any other forms, hence the rate of mechanical work does not contribute to the rate of entropy production. Thus, in internal polar thermoelastic solid continua the rate of mechanical work equilibrates with the rate of change of kinetic energy and the rate of change of strain energy. In this paper, this aspect of the physics is utilized to derive alternate forms of the first and second laws of thermodynamics applicable to internal polar thermoelastic solid continua. In these derivations of the alternate forms, the strain energy density is removed from the entropy inequality so that the resulting entropy inequality is purely a statement of the rates of entropies. This form is meritorious in demonstrating that the constitutive theories for the stress tensor and moment tensor are independent of the entropy inequality, hence the constitutive theories for the stress tensor and moment tensor have no thermodynamic restrictions. In this paper we consider both forms of the entropy inequality, the entropy inequality containing strain energy density and the one in its absence and other approaches and their applicability in the derivations of the constitutive theories for internal polar thermoelastic solid continua. The solid continua is assumed homogeneous and isotropic. The deformation and strain are assumed to be small.

Keywords

Internal polar thermoelastic solid continua, constitutive theories, generators and invariants, strain energy density, complementary strain energy density.