Pressure Distribution in a Hertz Circular Contact Affected by a Central, Circular Dent

Rolling contact fatigue is strongly influenced either by subsurface imperfections or by surface defects. The latter tend to become the major factor influencing contact fatigue. The first step to assess the effect of these defects upon contact fatigue life is to find the pressure distribution alterations they generate. This paper investigates the pressure riser effect around a circular dent placed centrally in a Hertz circular contact. The solutions of Erdogan are used as a start point. The superposition principle for the half-space is applied to these solutions to find the pressure distribution. The involved integrals are evaluated numerically. The dent affects the Hertz pressure only in its immediate neighborhood. It produces significant pressure risers near the outer edge of the dent and a central circular region free of pressure inside. In comparison to the case of smooth surfaces, the outer radius of the contact extends by a very small amount dependent on dent geometry. Calculations evidence the influence of dent geometry upon pressure riser effect.