A novel vibration based non-destructive testing for predicting glass ﬁbre/matrix volume fraction in composites using a neural network model /N.I.E. Farhana a , M.S. Abdul Majid a, ⇑ , M.P. Paulraj a , E. Ahmadhilmi b , M.N. Fakhzan a , A.G. Gibson - Farhana,N.I.E.