THE INFLUENCE OF ROUNDED EDGES ON INDENTATION BY FLAT PUNCH

The contact problem and stress state for indentation by a flat punch w ith rounded edges is studied. For the contact problem itself analytica l solutions are obtained for both surface pressure and interior stress fields. Cases of normal indentation and frictional contact, the latte r in both sliding or partial slip conditions, are all treated. The tra nsition from the Hertzian configuration to the contact between a nomin ally flat pad and contacting flat surface is discussed, and it is foun d that the strength of the contact decays surprisingly slowly. Regardi ng the von Mises yield parameter, there is range of configurations for which the strength is actually higher than the Hertzian one, and the strength decays only when the corner radii are very small. The present solution is therefore a realistic alternative to the classical rigid- flat punch idealization, and has particular application to fretting fa tigue tests.