Acoustic Emission Technique to Assist the Formula One Designer in Structural Design

One of the important features of the racing car is the power to weight ratio, and to this end, weight has been considerably reduced by the use of carbon fibre in the modern Formula One car. The weight saving obtained from carbon fibre components is utilised by the strategic placement of ballast (since there is a minimum weight limit set by the racing authority, the FIA), ordinarily as low as possible in the car. The placement of the ballast partially controls the position of the Centre of Gravity (CoG) and is the position through which inertial forces act. This is considered a primary performance measure along with the tyres, aerodynamics and engine power in fighting for podium positions. Designers of Formula One cars strive to find the minimum weight for that purpose. Colin Chapman, the legendary car designer, once said that his car only had to make the chequered flag of that race; it should fail immediately after that. The FIA have stringent technical regulations pertaining to driver safety. Included within these are mandatory testing procedures (which are witnessed) for the safety structures of the car, helping the driver to survive from high impact forces. Also to finish the race without failure, many of the critical components of the car are proof tested between races. Acoustic Emission is a passive testing technique that can detect the damage mechanisms of carbon fibre structures whilst under load. This technique will be shown in this paper to provide useful feed back to the designer to hone his design during the testing stage. This paper illustrates the use of the Felicity Ratio (FR) as used in the ASTM E1067, “Standard Practise for Acoustic Emission Examination of Fiberglass reinforced Plastic resin (FRP) Tanks and Vessels.”