Wear in friction brakes Wear in friction brakes

Parameters of friction systems decline in time by the process of wear. In friction brakes, the wear phenomenon is much more visible than in other friction systems. Wear itself is on one hand not desirable because of need for brake system parts replacement but sometimes is needed due to regeneration of the friction area which is damaged for example by temperature or aggressive ambient conditions. Wear can be fatal or catastrophic for the friction brake, leading to heavy damage or even to permanent loss of braking capability during operation. As the brake is one of the crucial safety systems in both aviation and road vehicles, it is necessary to know if and how wear will be present in friction brake system before the brake is allowed to be installed in the vehicle, especially one that carries people. Wear can be estimated via numerical methods for well-known brakes (i.e. materials) or it has to be tested using laboratory methods in order to check and prove or deny initial design assumptions. In this paper, the author describes the phenomenon of friction brake wear and laboratory-testing methods of friction materials wear using brake model test stand for aviation brake friction materials certification testing located in Institute of Aviation Landing Gear Laboratory. Author also presents sample data from aviation brakes materials testing in order to show how wear can affect friction brake performance and durability.