ABSTRACT
As discussed earlier, the DSC involves different stresses and strains in the material parts in the RI and FA states, respectively; see Fig. 4.1.
The latter causes relative motions or a diffusion-type process between the material parts in the RI and FA states. As a simplification, we can express a relationship between the strains in the RI and FA parts as [Fig. 4.1(b)]
(4.3)
c( ) ij
i , ij c( )
where
I
is the unit tensor and
is the relative motion tensor. If the material is assumed isotropic and
D
is considered to be a weighted (average) value,
can be expressed as a scalar as
wD
(4.4)
where
w
is a parameter. Then Eq. (4.3) becomes
(4.5)
Here
wD
, where 0
D
1 and
w
0. With the above definition of the relative motion parameter between the RI and FA strains, the first two terms in Eq. (4.2) can be expressed in terms of the RI strains, .
