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The continuum mechanics build up the continuous body from structureless pieces, socalled mass elements. If we would like to model a real substance, for example a chopped forage mass, as continuum, than we have to consider the mass element as the smallest part of mass in which anisotropy balanced. Inside such a particle the inner structure is neglected and the particle considered homogenous and isotrope. Although we cannot neglect that the mass because of its viscoelasticity has certain memory, which means that the inner energy of mass depends not only on the temporary value of state characteristics, but on total state history. For this reason to a thermodynamical description of viscoelastic body it is practical to adopt the so-called functional formalism. If we have not got exact knowledge about the physical structure of the substance's nonlinear behavior, we can also draw conclusions from its macroscopic manifestation with formally introducing inner variables. This does not mean that we give up the determination of physical meanings of inner values. It is better to say that the temporary uncertainty of physical meanings of inner values does not obsolete the mathematical determination of deformation and strain status.

Out of the thermodynamic process, the theory of non-equilibric thermodynamics render also the exact description of mechanical occurrence and interaction among forms of motion, so the knowledge of this process is essential for engineers dealing with transport processes. Each time, the thermodynamic method describes the form of mathematical relationships much shorter and more elegant for instance methods based on partial differential equations. It is an additional advantage that it eliminates uncertainties came about unreliability assumptions concerning the structure of matter. In the last case the chopped green forage masses are a proper example.