Composite sheet concept
In Composite material bulit structures, the basic unit of the whole laminate is the sheet. The three most frequent composite sheets are:
-
Unidirectional sheet:
All fibers are oriented in the same direction. Transversal isotrpy
is considered for this kind of sheet (same properties in all directions contained in a plane orthogonal to the fibers´plane).
-
Roving
sheet:
All fibers oriented in two orthogonal directions. The longitudinal fibers are crisscrossed with the transversal ones. 50% of the fibers can be oriented in each direction (equilibrated roving laminate), or there can be more fibers in one direction than in the other (non-equilibrated roving laminate). Orthotropy
is considered for this kind of sheet.
-
Mat sheet:
It is made of small cut fibers, oriented at random. Isotropy is considered (same properties in all directions) in the sheet plane.