An investigation of Hertzian contact in soft materials using photoelastic tomography

Hertzian contact of a rigid sphere and highly deformable soft solid is investigated using integrated photoelasticity. The experiments are performed by pressing styrene 15 mm diameter against 44 × 47 mm3 cuboid made 5% wt. gelatin, inside circular polariscope, with range forces. emerging light rays processed considering that the retardation each ray carries cumulative effect traversing contact-induced axisymmetric stress field. Then, assuming Hertz's theory valid, analytically calculated for compared to experimental one. Furthermore, finite element model process introduces displacements strains. Beyond qualitative comparison fields, experimental, theoretical, numerical results quantitatively in terms maximum equivalent stress, surface displacement, radius dimensions. A favorable agreement found at lower force levels, where assumptions Hertz hold, whereas deviations observed higher levels. major discovery this work that, location, all three components principal can be determined experimentally show satisfactory theoretical ones our measurement range. This provides valuable insight into problems since controls initiation plastic deformation or failure. measured displacement radii also reasonably agree ones. Finally, limitations arise due linearization problem explored.