ABSTRACT
A deforming material is considered to be a mixture of “continuous” and “discontinuous” parts. The latter can involve relative motions between particles due to microcracking, slippage, rotations, etc. As a result, the conventional definition of stress (
)
at a point
given by
(2.1a)
where
P
is the applied load and
A
is the area normal to
P
, does not hold; Fig. 2.1(a). The implication of is that the stress is defined at a point. In other words, all points in the material elements retain their neighborhoods before and during load. As a result, abrupt changes in the stress at neighboring points cannot exist, as no cracks or overlaps are permitted.
