Scientific Journal of KubSAU

We obtain a macroscopic criterion of fragile fracture (limit curve) when creating an isolated defect in the form of “narrow” undercut, when conformal mapping of the exterior of a unit circle on the plane with de-effect in the form of a recess defined by cut fiber-foam series. It is shown that in this case, the limit curve has the form identical to the case when the defect is set to "narrow" ellipse. The same crack oriented along either the compressive stress or tensile perpendicular stress. From here, we can suggest that the shape and geometric properties of a sufficiently "narrow" defect do not affect the values of the critical loads required to start its distribution

Considered theory of termofluktuacion strength of solids. Formulas for predicting long-term strength limits. Set the value of a safe low voltage of compression depends on the physical and mechanical material constants. For a number of technical glass received the numerical estimation of compressive stresses safety.