Innegrity LLC (Simpsonville, S.C.) has announced that its Innegra S high-modulus polypropylene (PP) fiber has been approved for use by the FIA (Federation Internationale de l’Automobile) for use in Formula 1 cars. Innegrity is a technical partner with the Brawn GP Formula One team, with whom it began collaborating in April 2008. To date, Brawn has captured eight Grand Prix victories in the 2009 season.

Innegra is a melt-spun PP fiber, with very low density and high modulus. It augments the toughness of a carbon fiber component when combined with carbon in a hybrid fabric or prepreg, says Innegrity. The PP fiber has been investigated as a replacement for aramid fiber in thin-skinned aerodynamic composites, such as wing parts, that have a tendency to disintegrate in a crash. Shards of debris can fly from a damaged car onto the track, often damaging tires and potentially causing more crashes during a race. Current FIA rules stipulate a design that minimizes and contains debris.

Innegra S performs as well as aramid fiber at less cost, reports Gary Savage, Brawn GP operations director, noting that the material also can be “dropped in” to current processes. Further, the material can be strategically placed to reduce weight and increase impact resistance and toughness in targeted part locations. As a result, the carbon/Innegra hybrid parts do not break or shatter as readily as all-carbon composites, but hold together, often with a hinged break.

“When the Innegra composite is damaged there is a tendency to tear and pull out fibers from the matrix rather than form sharp shards,” says Savage.