Friction materials evaluation equipment

Dynamometer and Vehicle Testing. Friction materials are evaluated in the laboratory by a great variety of tests and equipment. 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

In order to develop the proper dow pattern, knowledge of a material s dow properties is essential. Standard test equipment and procedures for evaluating sohds dow properties are available (6). Direct shear tests, mn to measure a material s friction and cohesive properties, allow determination of hopper wall angles for mass dow and the opening size required to prevent arching. Other devices available to evaluate sohds dowabiUty include biaxial and rotary shear testers. 

In recent years a variety of novel antifriction polymer-based materials have been developed and the known improved at different research centers and laboratories of the world. However, even a very learned expert in the field of friction is in a difficulty to evaluate truly the publicity and literary data when maJcing comparative analysis or selecting proper materials for particular friction applications. The reasons lie in the unavailability of common methods for friction testing of materials as well as evaluating criteria on the friction characteristics of materials. Explanation and selection of evaluating criteria largely depend upon the factors that influence the friction characteristics of polymers, and capabilities of the testing equipment. 

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