Production of aligned short-fibre composites

Jameson, Nicola (2014). Production of aligned short-fibre composites. University of Birmingham. M.Res.

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Abstract

This study investigated a manufacturing process to align short-fibres using a custom-made fibre chopper system. With this technique, continuous waste fibres are chopped, aligned and deposited onto an adhesive substrate to produce aligned short-fibre prepregs. Experimental methods were developed to address issues associated with calibration, a blade inspection criteria and the optimisation of producing parameters to achieve at least 60% fibre alignment in the prepreg. In order to ensure that the quality and the consistency of the chopped fibre ends were maintained, a criteria was developed to specify when the blade or the fibre chopper should be replaced. This production technique was used to manufacture 8-ply composites using the aligned short-fibre prepregs. Continuous fibre prepregs were also used to manufacture reference composites for comparison purposes. Non-destructive testing via visual inspection and ultrasonic c-scanning was used to determine the quality of the composites.
The physical and mechanical properties of the composite were established using conventional test methods. The main conclusions reached were: (i) The fibre-chopper-based technique developed in this study was capable of producing aligned glass and carbon short-fibre prepregs. (ii) The degree of fibre alignment was approximately 70%. (iii) The fibre volume fraction was found to be approximately 60%. (iv) The Young's Modulus of the aligned glass short-fibre composite was 33 GPa ; in comparison, the corresponding value for the continuous fibre composite was 39 GPa.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

Supervisor(s):