Similitude Law for the Creep-Adhesion Function in Dry Contact

This paper describes an experimental study on the dry friction-creep phenomenon. The study has been carried out on a test-rig. The simulated wheel has an elliptical area of contact similar to the actual locomotive wheel and is made of a 1070 plain carbon steel. The testing was conducted with variable contact stresses up to approximately 200,000 psi and equivalent speeds of approximately 5 miles per hour. The results of the test show that all the different creep-adhesion curves obtained by changing the normal loads can be reduced to one single dimensionless curve. This can be achieved if the actual nominal area of contact experimentally measured, is introduced in the corresponding expressions. A law of constancy of the product of the creep times the area of contact for dry, clean contact surfaces and a constant value of adhesion and normal load is presented.