Analysis of Continuous Fibre Composites

The greatest improvement in the strength and stiffness of a plastic is achieved when it is reinforced with uni-directional continuous fibres. The analysis of such systems is relatively straightforward. 

Consider a composite with continuous aligned fibres as shown in Fig. 3.3. If the moduli of the matrix and fibres are and Ef respectively then the modulus of the composite may be determined as follows. 

The applied force on the composite will be shared by the fibres and the matrix. Hence 

The strain, e, is the same in the fibres and matrix and is equal to the strain in the composite. 

If the fibres have a uniform cross-section, then the area fraction will equal the volume fraction, so 

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