· The modulus of the laminate
is a good measure of the degree of damage produced by fatigue. The diagram
shows the dependence of the composite modulus on cycle ratio.
· Transverse cracks in the laminae
and inter-laminate debonding are responsible for the range of modulus decrease.
Once the matrix has fractured the fibers carry the applied cyclic
load and these may also suffer fatigue if the applied stress is high enough. · Fiber fatigue continues at constant
modulus until enough fibers have broken to cause laminate failure.
From:
Schaffer, et al, "The Science & Design of Engineering Materials,"
Irwin (1995)
