Material properties and characterisation

In general, the thickness-permeability relation is stated in the following form 

CRTM involves periods of compression (h 0), and periods in which the mould components remain stationary Fibre reinforcement will 

This is most often taken to be a nonlinear elastic relation again, a wide range of expressions have been used in CRTM studies, from power-laws to relations involving the hyperbolic tangent. Equation [11.3] can also express the viscoelastic properties of fibrous materials (and hence the possible dependence on the rate of change of volume fraction, Vf, in Eq. [11.3]) and 

5 Compress and hold compaction tests performed on samples of a glass fibre chopped strand mat. 

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