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Carbon/Flax hybrid structures show improved vibration damping and impact behaviour

News International-French

18 Feb 2016

A UK-based consortium has developed carbon/flax hybrid structures with lower cost, higher vibration damping and improved impact behaviour compared to carbon fibre.

The CARBIO project has produced hybrid composites using layers of flax fibre and carbon fibre which have equal bending stiffness to all-carbon laminates, but with reduced cost, increased shock absorption and improved environmental impact.

The project has designed and manufactured a prototype automotive roof which combines the high strength and aesthetic appeal of carbon fibre with the low cost and vibration damping performance of flax. The prototype roof will be on display at the JEC World 2016 show on 8-10 March in Paris.

In addition, the carbon/flax micro-sandwiches have recently been shown to perform very well in automotive sled impact tests. A 50/50 carbon/flax hybrid crush structure was found to have equal specific energy absorption to an all-carbon structure, whilst exhibiting a safer mode of failure.

Brendon Weager, Technical Director at Composites Evolution, explains “we already knew that Biotex Flax could be used to reduce the cost and vibration of carbon fibre parts, but these outstanding impact test results came as quite a surprise to the R&D team! These low cost, fail safe hybrid crash structures will be of significant interest to automotive and motorsport engineers.”

An alternative approach is to create hybrid fabrics, where the carbon and flax fibres are co-woven to provide tunable performance, vibration damping and unique aesthetics at a lower cost than pure carbon fabrics. One example is Biotex Flax/Carbon 180g/m2 2x2 twill, a drapable hybrid fabric designed for complex structural and decorative parts in the automotive and sports sectors.

Hybrid flax/carbon spread tow fabrics are also possible. These offer superior properties due to the high degree of fibre alignment and low crimp, alongside highly attractive aesthetics, and are already being tested by manufacturers in the snow and water sports sectors.

The CARBIO project is part-funded by Innovate UK and the partners are Composites Evolution, SHD Composite Materials, KS Composites, Delta Motorsport, Jaguar Land Rover and Cranfield University.

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