Browsing by Author "Mahadik, Yusuf"

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    Coupon scale Z-pinned IM7/8552 delamination tests under dynamic loading
    (Elsevier, 2019-08-01) Cui, Hao; Mahadik, Yusuf; Hallett, Stephen R.; Partridge, Ivana K.; Allegri, Giuliano; Ponnusami, Sathiskumar A.; Petrinic, Nik
    Dynamic impact onto laminated composite structures can lead to large-scale delamination. This can be mitigated by the introduction of through-thickness reinforcement, such as z-pins. Here, mode I & II and mixed-mode delamination tests have been designed and conducted at high loading rate, for both unpinned and Z-pinned coupons to study the effect of rate of loading. It was found that the Z-pins were not effective in delaying the dynamic crack initiation or resisting the dynamic propagation of delaminations shorter than 5 mm. However, the further growth of cracks was substantially delayed by Z-pinning, especially for the pure mode I and mode I dominated failure modes. On the other hand, the effectiveness of Z-pins in shear tests was relatively modest. The mode I dominated delamination resistance of Z-pinned laminates was found to be sensitive to the loading rate.
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    Dataset for the publication "Coupon scale Z-pinned IM7/8552 delamination tests under dynamic loading"
    (Cranfield University, 2019-08-27 15:00) Cui, Hao; R. Hallett, Stephen; Mahadik, Yusuf; K. Patridge, Ivana; Allegri, Giuliano; Anusuya Ponnusami, Sathiskumar; Petrinic, Nik
    Datasets for a paper published in Composites Part A: Applied Science and Manufacturinghttps://doi.org/10.1016/j.compositesa.2019.105565The quasi-static tests were done at velocity of around 0.01mm/sDynamic tests were conducted at norminal velocity of around 4m/s, some of the WDCB tests were done at 7m/s.
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    Dynamic bridging response of through-thickness reinforcement in composite laminates
    (International Committee on Composite Materials, 2017-12-31) Cui, Hao; Melro, António R.; Mahadik, Yusuf; Yasaee, Mehdi; Allegri, Giuliano; Partridge, Ivana K.; Hallett, Stephen R.; Petrinic, Nik
    The present experimental study aims to extend the understanding of delamination crack bridging mechanisms in Z-pinned laminates subjected to highly dynamic loading conditions. The bridging response of single Z-pins was characterized with both quasi-static and high loading rate. Standard delamination tests of Z-pinned laminates were carried out at varying velocity. The experimental results at both length scales showed that Z-pin efficiency in improving delamination resistance decreases with increasing loading rate.