A new concept in friction testing

Abstract

Methods of measuring friction are reviewed and their shortcomings discussed. The advantages of using the wide range of test speeds, environmental conditions and recording facilities available on a tensile test machine are indicated and a new apparatus designed to fit a tensile tester is described. The design concepts are outlined in some detail and the factors limiting stick-slip motion are indicated. The apparatus can be used either for studies of materials or as an aid to product selection. Test results on a polyurethane rubber, covering a range of velocities and temperatures, illustrate the former, and tests on windscreen wiper blades under both wet and dry conditions illustrate the latter. Although primarily designed for testing the friction of polymers the apparatus is of universal application and can be used for measuring, against a chosen substrate, the coefficients of friction of metals, fabrics, paper, glass, leather, or any other material capable of being mounted in a vertical plane. It is not suitable for particulate matter such as sand, but could be used, for example, for studying the effect of floor finishes on a range of flooring materials.