الفهرس 
ch1Only 14 pages are availabe for public view
 |  | from | 186 |  |  |
| | | from | 186 | | |
Abstract
In the application of composite materials where the state
of stress may not be predictable or where it is known that the
stresses are approximately equal in all directions,
unidirectional composites may not be suitable. such
applications require composites that have approximately equal
strengths in all directions. Multilayered composites can be
constructed from layers of unidirectional laminates having
different fiber orientations so that the resulting composite is
.
essentially isotropic in a plane. Such composites have the
disadvantage that, although the overall composite is equally
strong in all directions, the surface layers, where the failure
is quite often initiated, are still very weak in the transverse
direction. In applications where protection from a corrosive
environment is an important factor, such as in storage tanks in
chemical industries, and in many applications in the automobile
industries, composites of unidirectional laminates do not solve
the problem completely. Thus, it is advantageous to have each
layer or lamina isotropic in some applications. An effective
way of producing an isotropic layer is to use randomly oriented
fibers as the reinforcement.
In the present work we studied the mechanical ·behaviour
and the manufacturing quality parameters for in-plane random
glass fiber/polyester composite plates produced by a hand
lay-up technique for a wide range of fiber weight ratio (Wf*=
15-55%).
A statistical analysis based on 2 and 3-parameter weibull
functions were used to predict a new empirical relations
between the fiber volume ratio V f and the other manufacturing
quality parameters fiber weight ratio Wf, void content V,
density p & moisture content H, also a new relations between
c