Talk Composites - The Forum for Advanced Composites

Opinions please: Roll-over protection for a Marcos

http://www.talkcomposites.com/Topic14047.aspx

By Ian Mantula - 12/3/2014 4:42:52 PM

Hello,
Be gentle I'm new here!

I have just started to consider some carbon fibre parts for my Marcos Mantula. The car needs various parts before it's finished. One of those was to be a steel roll-over bar. However, my recent discovery of the possibilities of carbon fibre composites got me thinking. Is it possible for an enthusiastic amateur to build a lightweight integrated crash structure that was genuinely capable of helping with protection? What I'm thinking of is a structure that was not obvious once the interior had been trimmed. When working with steel roll-over structures there is plenty of prior knowledge as to what works and what would fail. Can this be true with Carbon fibre composites, or is this a black art known only to a few? How would I learn?

In case you are wondering the Marcos is a GRP bodied two seater sports car with a steel chassis and in mine a 4.6 litre V8... The top of the chassis structure is at shoulder height.
By Warren (Staff) - 12/22/2014 10:06:41 AM

You have to engineer such a structure from 2 perspectives. IN the roll over situation, deformation needs to be limited to protect the occupants.  An element of energy absorption is also needed.

THe crash structure on an elise is mostly bothered with the later.  It works by absorbing energy through its own destruction. It is entirely outside of the "safety cell" so it doesnt really matter if the structure is destroyed in the process.

A roll structure has the difficult job of both roles. Primarily energy absorbtion is sacrificed for sheer strength to protect the safety cell, but some absorption is necessary.

There is no reason why a composite roll over protection system isn't doable. As proven in F1 and certain other high level motorsport, it is possible with the research and development.

Problem of that is the cost and man hours to get it right.