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Role of Laminate Thickness on Sequential Dynamic Delamination of Curved [90/0] CFRP Composite Laminates

Uyar, Imren
Tasdemir, B.
Yavas, D.
Çöker, Demirkan
In aerospace industry, high demand for the lightweight structures are fostering the use of carbon fiber reinforced polymer composites in a wide variety of shapes, as primary load carrying elements. However, once a composite laminate takes a highly curved shape, such as an L-shape, interlaminar stresses augmented in the curved region cause highly dynamic delamination nucleation and propagation. This paper provides experimental observations of dynamic delamination failure in cross-plied L-shaped composite laminates under quasi-static shear loading for varying laminate thickness. In the experiments, load-displacement curves are recorded and dynamic delamination events areas captured using a million fps high speed camera. In our previous work, two distinct types of failure modes have been identified depending on the laminate layup: (i) formation of multiple delaminations leading two single load drop in its load-displacement curve during the failure of unidirectional laminates, [0](17), and (ii) formation of sequential delaminations associated with each discrete load drop in its load-displacement curve were during the failure of cross-ply laminates, [90/0](17). Accordingly this current study shows that formation of sequential delaminations is independent from the laminate thickness.