A Practical Method for Determining Contact Stresses in Elastically Loaded Line Contacts

Abstract

Forecasting life of a cylindrical rolling element under cyclic elastic loading and with misalignment requires determining the exact shape of the mutual contact as well as its area. The classical Hertzian equations for predicting half width of the contact area and resulting mean and maximum stresses are only sufficient to determine the stress levels for symmetrically loaded, uncrowned cylinders under static and dry surface conditions. However, the theory fails in predicting stress distributions for crowned cylinders, symmetrically or asymmetrically loaded and does not describe end of contact phenomena. Toward this end a method has been developed for recording the contact area or “footprint”, created by the symmetrical or asymmetrical static loading of a partially crowned, cylindrical steel roller on an unlubricated flat steel plate. Analysis of the “foot print” yields the load and stress distributions over the contact area and may be employed as a practical tool in experimental investigations and product design work.