Why composites in form of laminates

[chandran]

why composites are built in form of laminates(laminas with various orientation)?. why can't
a single lamina serve the purpose?

how a single laminate property is different from a single lamina property

 

[FredGarvin]

Lamina plys are very very thin, on the order of, say 100 micrometers. They are not very effective on their own. The other bog reason is that material properties can be custom formed to the expected loads the part will see or how the part is expected to be machined.

Also remember this...the major contributor to the strength of the material is the fibers. Therefore you can have a unidirectional laminate, but that really provides you strength in one direction only.