Advanced natural z-pinned composite materials in offshore wind
turbine blades to improve impact resistance under extreme
conditions
Background:
FRP composite material design technology has become a main factor in structural integrity to design of
composite sub-structures in various engineering disciplines. In particular case offshore wind turbine blades
are typically manufactured from FRP composites and delamination failure is an important issue in these
structures. In extreme conditions, like ice impacting, multiple delaminations with a triangular shape is
found in different parts of a composite wind turbine blade, introducing local damage, which can cause
catastrophic failure under various loading conditions such as post-impact, fatigue and buckling. Most of
previous researches were focused on the impact behaviour of delaminated composite structures
manufactured from synthetic fibers in 2D with limited improvements. Recently we have developed new
composite structures with 3D fibre configuration. Preliminary research has shown that the new composites
have much better performance against various failure conditions such as delamination failure. However
more work is needed to understand the interlaminar and intralaminar fracture mechanisms in 3D FRP and
also the interaction between fibre and matrix phases. Support for a PhD student is needed to undertaken
this research.
Key objectives and work plan:

To introduce advanced 3D composite materials using a hybrid natural/synthetic system. A new
combination of natural (Flax) in z-pinning of hybrid kevlar/carbon fabric reinforced composite material with
high strength and modulus properties will be produced.

To investigate the dynamic response of advanced composite sub-structures applied in wind turbine
blade, commonly used in the composite structures, to impact loading. Importantly, the dimension and
position of delaminations in the composite panels used in this study will be chosen to accurately represent
those proposed for the demining structures.

To advance the numerical studies for simulation of the impact response of advanced multidelaminated natural 3D hybrid composite structures. Within ANSYS and LS-DYNA, it is possible to conduct
advanced calculations of impact loading response. The predictions will be used for assessing the risk for
delamination failure of different type of structures and structural elements under impact loading.
For an informal discussion on the project please contact Dr. Hessam Ghasemnejad:
h.ghasemnejad@kingston.ac.uk or 020 8417 4738
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Recent relevant publications
1. H. Ghasemnejad, V.R. Soroush, P.J. Mason, B Weager, To improve impact damage response
of single and multi-delaminated FRP composites using natural Flax yarn, in 'Materials and
Design', In press, Elsevier, (2011).
2. H. Ghasemnejad, L. Occhineri, D.T. Swift-Hook, Post-buckling failure in multi-delaminated
composite wind turbine blade materials’, in 'Materials and Design', 32 (2011), pp. 5106–511,
(2011).
3. J.M. Pereira, H. Ghasemnejad, J.X. Wen, V.H.Y. Tam, “Blast response of cracked steel box
structures repaired with carbon fibre-reinforced polymer (CFRP) composite patch”, in
'Materials and Design', doi.org/10.1016/j.matdes.2010.12.045, Elsevier, (2011).
4. H. Ghasemnejad, T Vineet, H. Hadavinia, "Mixed-mode delamination failure of z-pinned
hybrid laminated composites" in 'Key Engineering Materials', 452-453, pp. 453-456. ISSN
1662-9795 (2011).
5. H. Ghasemnejad, A.S.M. Furquan, P.J. Mason, "Charpy Impact Behaviour of Single and MultiDelaminated Hybrid Composite Beam Structures" in 'Materials and Design', 31(8), Elsevier,
pp. 3653-3660., ISSN 0261-3069, (2010).
6. H. Ghasemnejad, H. Hadavinia, A. Aboutorabi, "Effect of delamination failure on the
crashworthiness of hybrid composite box structures", in 'Materials and Design', 31(3),
Elsevier, March, pp. 1105-1116., (2010).
7. M.M.N Esfahani, H. Ghasemnejad, P.E. Barrington, "Experimental and numerical buckling
analysis of delaminated hybrid composite beam structures" in 'Applied Mechanics and
Materials', 24-25, pp. 393-400. ISSN 1662-7482 (2010).
8. H. Hadavinia, H. Ghasemnejad, "Effects of Mode-I and Mode-II interlaminar fracture
toughness on the energy absorption of CFRP twill/weave composite box sections" in
'Composite Structures', Elsevier, 89(2) pp. 303-314. (2009)
9. H. Ghasemnejad, B.R.K. Blackman, H. Hadavinia, B Sudall, "Experimental studies on fracture
characterization and energy absorption of GFRP composite box structures" in 'Composite
Structures', Elsevier, 88(2) pp. 253–261. (2009) [Listed in the top 25 hottest articles in
Composite Structures].
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