List all possible fracture mechanisms under which the unidirectional composites fail. Briefly explain and describe the related m
aterial behavior for each mechanism. It is seen that the composite longitudinal strength and stiffness and transverse stiffness are improvements over the corresponding matrix properties due to the presence of fibers. However, a unidirectional composite subjected to transverse loads exhibit lower strength ranges than does the matrix material. Why? Use diagrams or equations as needed.
Describe the damage accumulation process in cross-ply laminates ([0/90/90/0]) under longitudinal loading step by step. Also, estimate the elastic modulus of the composite using EL and ET (for longitudinal and transverse modulus of each ply) assuming all plies are of same thickness.
