Experimental investigation on the influence of crack front to fiber orientation on fatigue delamination growth rate under mode II

The knowledge of delamination modes and growth rate during the operating life of a composite structure is of primary concern. Several studies aimed at formulating a criterion for delamination onset and growth prediction have been published and experimental testing performed for validating theoretical models.This paper, presents the results of fatigue interlaminar fracture growth tests on laminated composites with different stacking sequences. The main objective of the work was to verify the influence of the angle between the crack front line and the fibers on the delamination growth rate, under mode II. The behavior of specimens having different stacking sequences was investigated using the end-notched flexural test method. The observed delamination growth rate as function of ΔGII for different lay-ups is reported and critically analysed.