Page 365 - Mechanics Analysis Composite Materials

350 Mechanics and analysis of coniposite materials

7.4. Manufacturing effects

As was already noted, composite materials are formed in the process of
fabrication of a composite structure, and their properties are strongly dependent on
the type and parameters of processing. This means that material specimens that are
used to determine mechanical properties should be fabricated with the same
manufacturing method that is expected to be used to fabricate the structure under
study.
To demonstrate direct correlation that can exist between processing and material
properties, consider the process of circumferential winding on the cylindrical surface
as in Fig. 7.43. As a rule, the tapes are wound with some overlap wo shown in
Fig. 7.44(a). Introducing dimensionless parameter

Fig. 7.43. Winding of a circumferential layer. Courtesy of CRISM.

mi
- 1 .......
C D

- - - . - . .

Fig. 7.44. Circumferential winding with (a) partial overlap wo < w and (b) complete overlap wg = w.