Audi Going To Lightweight GFRP Springs This Year

Audi has announced this year its first lightweight suspension springs made of glass fiber-reinforced polymer (GFRP) will see production in an upper mid-sized model yet to be disclosed, with more cars to follow.

The incremental but not insignificant replacement for steel coil springs is being touted as saving 40 percent in critical unsprung weight for the car, and requiring less energy to produce.

While no fuel economy savings are being touted, the non-corroding springs do promise a mildly improved picture for the German automaker’s upscale products. Not only will they hold up to chips and road salt, but they may even provide a slightly more complaint ride on rough pavement (as pictured).

“The GFRP springs save weight at a crucial location in the chassis system. We are therefore making driving more precise and enhancing vibrational comfort,” said Dr. Ulrich Hackenberg, member of the Board of Management for Technical Development at AUDI AG.

GFRP (left) compared to steel.

GFRP (left) compared to steel.

Audi says the green GFRP spring will weigh 3.5 pounds (1.6 kg), saving unsprung weight over steel which would normally weigh 6 pounds (2.7 kg).

The molded springs are formed around a millimeters-wide core of long glass fibers impregnated with epoxy resin which are twisted together.

Additional fibers are machine-wrapped around this core at alternating angles of plus and minus 45 degrees to the longitudinal axis. The finished product is cured in a 100 degrees Celsius oven, and Audi says the spring’s plies provide both tension and compression and mutually support one another to “optimally absorb stresses.”

“The GFRP springs can be precisely tuned to their respective task, and the material exhibits outstanding properties,” said the company. “It does not corrode, even after stone chipping, and is impervious to chemicals such as wheel cleaners.”