Giannis
Staff member
Giannis
Audi bringing new lightweight springs to production models
GFRP stands for Glass Fiber Reinforced Polymer, a relatively new material that is already used in structural and naval, amongst others, applications. Very recently this material made its first step in certain automotive applications, most importantly suspension components. The very recently introduced Renault Megan RS 275 Trophy-R comes with GFRP springs made from the Italian supplier Sogefi, while ZF - famous for their gearboxes - also offers this technology.
But it's about time the Germans step into this new material with full power, as Audi just announced that they will be introducing light-weight GFRP springs in an upper mid-size model before the end of the year. Audi engineers state that a GFRP spring is 40% lighter than a conventional steel one, as it weights 1.6 kg compared to nearly 2.7 kg for a steel spring with the same properties, thus providing a great advantage in reducing the unsprung mass, a crucial parameter that affects a car's dynamic characteristics. On top of that, the GFRP springs do not corrode, even after stone chipping, and are impervious to chemicals such as wheel cleaners. They also require far less energy for their manufacturing, compared to steel springs.
Audi's press release states that the brand's GFRP springs are developed "in collaboration with an Italian supplier", but does not clearly state which one. Our only concern is how Audi will deal with the creep effect (*), a characteristic of the GFRP material. While GFRP as a material has many advantages, we still have a few questions, regarding the predicted lifetime of GFRP suspension components and the degradation of their properties in respect to time.
(*) Creep is the phenomenon under which a material continues to deform under a constant load.
Source: [Audi]
Audi bringing new lightweight springs to production models
GFRP stands for Glass Fiber Reinforced Polymer, a relatively new material that is already used in structural and naval, amongst others, applications. Very recently this material made its first step in certain automotive applications, most importantly suspension components. The very recently introduced Renault Megan RS 275 Trophy-R comes with GFRP springs made from the Italian supplier Sogefi, while ZF - famous for their gearboxes - also offers this technology.
But it's about time the Germans step into this new material with full power, as Audi just announced that they will be introducing light-weight GFRP springs in an upper mid-size model before the end of the year. Audi engineers state that a GFRP spring is 40% lighter than a conventional steel one, as it weights 1.6 kg compared to nearly 2.7 kg for a steel spring with the same properties, thus providing a great advantage in reducing the unsprung mass, a crucial parameter that affects a car's dynamic characteristics. On top of that, the GFRP springs do not corrode, even after stone chipping, and are impervious to chemicals such as wheel cleaners. They also require far less energy for their manufacturing, compared to steel springs.
Audi's press release states that the brand's GFRP springs are developed "in collaboration with an Italian supplier", but does not clearly state which one. Our only concern is how Audi will deal with the creep effect (*), a characteristic of the GFRP material. While GFRP as a material has many advantages, we still have a few questions, regarding the predicted lifetime of GFRP suspension components and the degradation of their properties in respect to time.
(*) Creep is the phenomenon under which a material continues to deform under a constant load.
Source: [Audi]
Press Release:
Audi is reinforcing its leading role in automotive lightweight construction. The company is introducing new, lightweight suspension springs made of glass fiber-reinforced polymer (GFRP) in an upper mid-size model before the end of the year.
The GFRP spring, which Audi developed in collaboration with an Italian supplier, even looks different than a steel spring. It is light green, the fiber strand is thicker than the wire of a steel spring, and it has a slightly larger overall diameter with a lower number of coils. Most importantly, however, it is some 40 percent lighter. Whereas a steel spring for an upper mid-size model weighs nearly 2.7 kilograms (6.0 lb), a GFRP spring with the same properties weighs just approximately 1.6 kilograms (3.5 lb). Together the four GFRP springs thus reduce the weight by roughly 4.4 kilograms (9.7 lb), half of which pertains to the unsprung mass. “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.
The core of the springs consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core — which is only a few millimeters in diameter — at alternating angles of plus and minus 45 degrees to the longitudinal axis. These tension and compression plies mutually support one another to optimally absorb the stresses acting on the component. In the last production step, the blank is cured in an oven at temperatures of over 100 degrees Celsius.
The GFRP springs can be precisely tuned to their respective task, and the material exhibits outstanding properties. It does not corrode, even after stone chipping, and is impervious to chemicals such as wheel cleaners. Last but not least, production requires far less energy than the production of steel springs.
http://www.germancarforum.com/audi-bringing-new-lightweight-springs-to-production-models
