Braking Power: Low-Weight and High-Durability Brake Rotors
Few things could be more valuable to automotive manufacturers these days than innovations that lower the cost of ownership of a vehicle. With gasoline prices at historic highs, consumers are more likely these days to consider cars and trucks that are easier on the pocketbook, and cheaper to maintain over the long haul.
One way for manufacturers to achieve that is by decreasing a vehicle's curb weight and using parts that don't need replacing. Take something as superficially mundane as brake rotors. They have, for decades, been made of cast iron, which is heavy and prone to overheating and wear, and eventually has to be replaced.
But NYU-Poly may soon help in developing a low-weight and high-durability rotor. Researchers at the university are collaborating with Calumet, Michigan-based supplier REL, Inc. to build a rotor that weighs 60 percent less, and is immune to the damaging temperature
and pressure differentials that plague traditional brakes. The new rotors may, in fact, never have to be replaced.
Overseeing the NYU-Poly side of the equation is Mechanical and Aerospace Engineering Associate Professor Nikhil Gupta who, with his Composites Materials and Mechanics Lab, is near to perfecting the technology that makes these rotors a possibility. The solution lies in a composite of aluminum and glass ceramic. The product isn’t a pipe dream: Gupta and his lab are working with REL toward production this year of a prototype rotor that may revolutionize a market valued at $10 billion annually.
Light-weight composite brakes shaves 30 pounds from a mid-size sedan composite of aluminum and glass ceramic.
In essence, Gupta and REL are developing a one-piece aluminum rotor impregnated at the rim with glass ceramic strands that tolerate high temperatures. The result is a lighter disk whose composition is optimal for autos: even under high-stress breaking where disk temperatures can quickly spike to the melting point of aluminum.
The new disk tolerates those temperatures and diffuses the heat throughout the rotor for faster cooling. "The temperature of the brake shoes can be several hundred degrees Celsius," explains Gupta, "so you want a rotor that has a different set of properties at the rim than at the hub, or a gradient structure" he says. "The gradient material allows us to selectively provide reinforcement where additional strength is needed."