EFFECT OF CHANGES IN CONTACT GEOMETRY ON SHAKEDOWN OF SURFACES IN ROLLING SLIDING CONTACT

During repeated rolling of a point contact, changes in contact geometry are caused by plastic flow in the lateral direction. It is proposed, and supported by experiment, that the contact area changes from elliptical to near-rectangular. In consequence the pressure distribution changes from ellipsoidal (Hertzian) to being nearly uniform in the lateral direction [a distribution investigated by Kunert, Forschung auf dem Gebiete des Ingenieurwesens, Vol. 27, p. 165 (1962)]. Using Melan's theorem, shakedown limits have been found which enable the steady-state geometry of the contacting surfaces to be predicted for an elastic-perfectly plastic material. Experiments performed by the authors and other researchers were found to be in good agreement with predictions.