Thermodynamic consistency of nonclassical continuum theories for solid continua incorporating rotations

In this paper, we present derivations of three micropolar nonclassical continuum theories in which a material point always has displacements u as degrees of freedom. Additionally, (i) in the first nonclassical continuum theory (NCCT) we consider internal or classical rotations (i)Theta (known) due to skew symmetric part of the deformation gradient tensor; (ii) in the second NCCT, we consider both internal rotations (i)Theta and external or Cosserat or microrotations (e)Theta (unknown degrees of freedom); (iii) in the third NCCT, we consider Cosserat rotations (e)Theta only; hence, (i) Theta are neglected in this NCCT. We examine consistent choice of kinematic variables, modifications of conservation and balance laws of classical continuum theories (CCTs) due to the presence of new physics of rotations and determine whether the consideration of rotations requires additional balance laws. NCC theories derived here are examined for thermodynamic and mathematical consistency and are compared with published works. Model problem studies are also presented.

Automated summary

This paper presents derivations of three micropolar nonclassical continuum theories and analyzes their properties. The modifications of kinematic variables and balance laws due to the presence of rotations are examined, and the consistency of these theories is verified and compared with existing works.