Photoelastic and Numerical Analysis of a Sphere/Plan Contact Problem

Stress analysis in the neighborhood of contact zones can help improve the design and the durability of mechanical components. A numerical solution for a three-dimensional contact problem (sphere/plan), under a normal load, is developed. An experimental analysis with the same load is conducted on a regular polariscope with a three dimensional model for comparison purposes with the finite element solution. The stress field is locked inside the model with the help of the stress freezing technique. The stress field is then determined, on a regular polariscope, for slices cut in the model for comparison purposes with the finite element solution. The experimental isochromatic and isoclinic fringes are compared with the simulated ones. Another comparison is made by using stress values; the simulated principal stresses differences are obtained for a slice located along the load direction. The obtained graph is validated by the experimental data obtained by exploiting the photoelastic fringes recorded on a white field polariscope for the corresponding slice. Good agreements are observed; for a same slice stresses decrease along the vertical axis of symmetry as me move away from the contact area.