Thermodynamical Discussions for Standpoint of Principle of Material Frame Indifference

In continuum mechanics it is not clear what kind of principle is equivalent to the principle of material frame indifference (PMFI). In the present paper, it is first shown that not only mechanical conservation laws but also rules of frame transformation for constitutive quantities and source quantities are simultaneously derived by changing frame on the assumption that the forms of the first and second laws of thermodynamics are invariant for the changes of frame. Next, considering whether the reverse proposition is true or false, an explanation is given for the relation between the PMFI and the invarinance of the laws of thermodynamics for the changes of frame. Then the essential standpoint of PMFI is definitely placed, making the relation between the PMFI and the frame-invariance of Clausius-Duhem inequality clear. Moreover it is indicated that the method which derives the conservation laws using the changes of frame is equivalent to both the principle of virtual power and the method by Green-Rivlin.