Creating a Carbon Fiber Composite with Improved Elastic Properties

Overview

A critical factor to a car’s speed and efficiency is its weight. A lighter car is faster, more agile, and requires less energy. Polymer matrix composites (PMCs) are attractive because of their high rigidity and strength and their low weight. However, current PMCs are too brittle to see widespread use. By varying the reinforcing and laminating materials, PMCs can be altered to fit specific applications requiring specialized properties. The purpose of this project was to create a PMC with increased flexural strength and elongation at failure and decreased elastic modulus than current resin-matrix PMCs (RPMCs) while maintaining a comparable ultimate strength. High-durometer silicone was chosen as the experimental matrix because of its elastic properties as well as its comparable strength to plasticized epoxy resins. A successful silicone-matrix PMC (SPMC) could present improved resistance to impact, deformation, and compression — all weaknesses of current RPMCs. Two composites were fabricated: one using epoxy resin and the other using silicone rubber as the matrix. Both were cured at 200F. Testing maximum load and four-point flexural strength, the mechanical properties of both PMCs were compared. The SPMC samples had higher displacement at failure and increased elasticity, but a lower maximum load. The average load at failure of the RPMC was 4225 lbf with 8% elongation at failure. The SPMC showed a significantly lower average load at failure at 847 lbf, slightly higher elongation at failure, 10%, and severely weakened flexural strength at 20 lbf before yielding. Future testing may vary the type of silicone used as the matrix to maintain flexibility but increase strength. Creating a more elastic PMC with improved durability would allow a wider proliferation of PMCs in automotive engineering and could allow faster and more efficient vehicles than ever before.

Competition history

• AJAS 2020 Category not listed

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