Newly developed theoretical solution and numerical model for conformal contact pressure distribution and free-edge effect in spherical plain bearings

• We proposed a theoretical model for conformal contact in spherical plain bearings.
• Numerical models were investigated to verify the accuracy of theoretical model.
• The phenomena and laws of free-edge effect in bearings were researched.
• Free-edge effect creates high pressure gradient and concentration near free edges.
• The pressure concentration factor varies linearly with contact radius proportion.

Based on the Fang model for complete spherical surfaces, this paper proposes a new accurate theoretical solution for calculating the conformal contact pressure in spherical plain bearings. Our study investigated extensive 3D finite element (FE) models of bearings verified by optical experiments and then further improved. Because the bearing width is finite, free-edge effect, which causes a deviation in pressure between the two directions, is prominent. This effect varies with the clearance and load and produces a high stress gradient and concentration near the edges. There is an approximate linear relationship between the pressure concentration factors and contact radius proportion.