In-Situ Observation of Damage Evolution in Quasi-Isotropic CFRP Laminates

In this work, a Digital Image Correlation (DIC) impaired with high resolution optical system is applied to capture the damage evolution in composites laminates in-situ. The developed method enables to measure the local (micro scale) deformation across the thickness on the free-edge (8-plies laminate) subjected to a quasi-static tension. Three groups of specimens are prepared by arranging plies at different stacking sequence, and the formation of strain localization, initiation of matrix crack, delamination and other damages are acquired. It is obtained that matrix cracking is the primary and dominant form of damage and it usually occurred in the 90°-plies. However, the orientation and quantity of matrix cracks are highly affected by the stacking arrangement of the plies.