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Interaction of Z-pins with Multiple Mode II Delaminations in Composite Laminates

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Abstract

The application of Z-pinning is a subject of great interest in the field of through-thickness reinforcement (TTR) of composite laminates. To date, the majority of Z-pin characterisation work has been conducted on fracture coupons containing a single embedded delamination, which is often not representative of real failure of reinforced composite structures in service. In this investigation a test procedure to produce two independent Mode II delaminations was developed to analyse their interaction with a region of Z-pin reinforcement. Initially numerical models were used to optimise the chosen configuration. Experimental results show in detail the response of Z-pins to two independent delaminations. These results highlight the ability of the Z-pins to effectively arrest mode II delaminations at multiple levels through the sample thickness. Additionally they provide a much needed data set for validation and verification of Z-pin numerical modelling tools.

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Acknowledgments

The authors would like to acknowledge Rolls-Royce plc for their support of this research through the Composites University Technology Centre (UTC) at the University of Bristol, UK.

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Correspondence to M. Yasaee.

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Yasaee, M., Mohamed, G. & Hallett, S.R. Interaction of Z-pins with Multiple Mode II Delaminations in Composite Laminates. Exp Mech 56, 1363–1372 (2016). https://doi.org/10.1007/s11340-016-0175-9

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Keywords

  • Composite
  • Through thickness reinforcement
  • Z-pin
  • Multiple delaminations
  • Mode II
  • CFRP