Abstract: In view of the stress field distribution of glass indentation caused by the spherical support of tempered vacuum glass, the Hertzian indentation equation was modified by using contact mechanics, and the three-dimensional stress field equations were derived. At the same time, the stress intensity factor of fully developed conical crack was numerically solved. The numerical results show that all the principal stresses inside the contact area between the sphere and the glass are compressive. The principal stress σ₁ leads to the initiation of the crack, while the principal stress σ₂ forms the annular crack. The minimum principal stress is perpendicular to the glass surface, and then deviates from the contact edge, which forms the approximately parallel curves. And the maximum tensile stress is always perpendicular to these curves. Therefore, under the action of the maximum principal tensile stress, the crack follows the trajectory of the minimum principal stress. The stress intensity factor at the crack tip determines the fracture toughness. With the crack propagation, the stress intensity factor decreases. After a certain distance from the surface, the stress intensity factor reaches the critical value and the crack stops. The normalized stress intensity factor under different indentation loads is a set of curves with similar shapes.

Key words: tempered vacuum glass, support, indentation stress field, fracture toughness, stress intensity factor