Chemistry Reference
In-Depth Information
(26)
Because of no stress is transmitted in the voids, in and so:
(27)
Where is composite average stress, is fibers average stress and is matrix
average stress. Similarly to the composite stress, the composite strain is
defined as the volume average strain, and is obtained as:
(28)
Despite the stress, the void in strain does not vanished; it is defined in
term of the boundary displacements of the voids. So, because of the void
fraction is usually negligible. Therefore, last term in Eq. (26) could be
neglected and the equation corrected to:
(29)
The average
stiffness
of the composite is the tensor
C
that related the aver-
age strain to the average stress as follow equation:
(30)
The average
compliance S
is defined in this way:
(31)
Another important concept is the
strain concentration
and
stress concen-
tration
tensors
A
and
B
which are basically the ratios between the average
reinforcement strain or stress and the corresponding average of the com-
posites.
(32)
