INSENSITIVITY OF MATERIALS TO THE EXCHANGE OF DEFORMATIONS PATHS - 1, 2.

The main object of theory of materials (theory of constitutive equations) is to direct and to arrange the mechanical macroexperiment. In Part I of this paper a definition of the insensitivity semigroup of a material is given. It is a set of such all mappings of deformation paths, which do not influence the final value of stress. The algorithm for deriving the general constitutive operator insensitive with respect to prescribed semigroup is given. In Part II, the aim is to define precisely a common notion of material viscosity in mechanics. It is proposed to understand by motion of viscosity the dependence of the response of a material on acceleration, retardation and freezing of the deformation processes. This conception is precisely defined by a notion of the inviscosity semigroup of a material. On the basis of this definition the corresponding classification of materials is obtained. As limit cases, the totally viscid materials and the completely inviscid materials can be considered. The general form of constitutive operators for different types of viscosity is obtained.