Cui, HaoYasaee, MehdiKalwak, GordonPellegrino, AntonioPartridge, Ivana K.Hallett, Stephen R.Allegri, GiulianoPetrinic, Nik2017-05-172017-05-172017-04-13Hao Cui, Mehdi Yasaee, Gordon Kalwak, Antonio Pellegrino, Ivana K. Partridge, Stephen R. Hallett, Giuliano Allegri, Nik Petrinic, Bridging mechanisms of through-thickness reinforcement in dynamic mode I&II delamination, Composites Part A: Applied Science and Manufacturing, Volume 99, August 2017, pp198-2071359-835Xhttp://dx.doi.org/10.1016/j.compositesa.2017.04.009https://dspace.lib.cranfield.ac.uk/handle/1826/11903Z-pin through-thickness reinforcement is used to improve the impact resistance of composite structures; however, the effect of loading rate on Z-pin behaviour is not well understood. The dynamic response of Z-pins in mode I and II delamination of quasi-isotropic IM7/8552 laminates was characterized experimentally in this work. Z-pinned samples were loaded at both quasi-static and dynamic rates, up to a separation velocity of 12 m/s. The efficiency of Z-pins in mode I delamination decreased with loading rate, which was mainly due to the change in the pin misalignment, the failure surface morphology and to inertia. The Z-pins failed at small displacements in the mode II loading experiments, resulting in much lower energy dissipation in comparison with the mode I case. The total energy dissipation decreased with increasing loading rate, while enhanced interfacial friction due to failed pins may be largely responsible for the higher energy dissipation in quasi-static experiments.enAttribution-NonCommercial-NoDerivatives 4.0 InternationalZ-pinMode IMode IIDelaminationDynamicArticle