Influence of the Test Velocity on the Friction Coefficient in High-Strength Bolted Connections Under Cyclic Load

To determine the dependence of the test velocity on the friction coefficient (mu) in high-strength preloaded connections, experimental investigations are performed on bolted joints typical of rail vehicle construction. This is achieved through slip load tests following the procedure outlined in Annex G of EN 1090-2, well as high-speed tensile tests, subsequently comparing the resulting friction coefficients. Furthermore, the influence of a previously acting cyclic load for two different friction surface conditions is presented. As a result, an influence of velocity on the friction coefficient could not be definitively determined. However, the increase in the friction coefficient by applying a previously acting cyclic load as well as through the use of friction-increasing films was successfully demonstrated.