Data were presented in [i, 3, 5, 6] on the fracture of glass-plastics under long-term loading. According to the theory in [2], in the presence of a macrocrack, the parameters of the kinetics of crack growth are linked with the theological properties Of the con~osite and itscrack-resistance characteristics under short-term static loading.The main goal of the present study is to experimentally verify certain premises of the mechanics of delayed fracture of anisotropic viscoelastic bodies presented in [2] and to determine the feasibility of using the results in [2] to describe the kinetics of crack growth in polymer composites.The main postulates of the theory in [2] are as follows. The composite is modeled by an anisotropic viscoelastic body. The composite examined was characterized by shear creep, when the creep strains in the direction of the warp and weft can be ignored compared to creep strains in shear. Fracture is described within the framework of the generalized ~k model. Meanwhile, it is assumed that the crack-tip opening 6 and the size d of the prefracture zone are constant at each moment of time for the growing crack.The following equation is the equation of the main period of crack growth, which in the case of a macrocrack (i.e., a crack satisfying the condition d << s where s is the length or half-length of the crack) makes the main contribution to the time to rupture = 1 + qQ (q),

No abstract

No abstract

Electrical conductivity of Li(Na,K)2O‐Nb2O5‐P2O5 glasses and glass‐forming melts has been measured in a wide temperature range (298‐1173 K). Logarithm of the preexponential factor and activation energy of migration have been determined. Mixed alkali effect has been observed in niobophosphate glass‐forming melts. Diffusion coefficients for Li+, Na+, and K+ ions have been calculated. The influence of the type of alkali ion and Nb2O5 content on the diffusion coefficients has been determined.

No abstract