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Penetration experiments on glass found in the literature show that the target fails ahead of the projectile (the “failure wave” is faster than the penetration velocity). Thus, during penetration, the projectile is in contact with failed glass ahead; consequently, the properties of failed material are required for accurate numerical simulations. This paper shows, using a confined compression experiment of a cylindrical specimen combined with an analytical model for interpretation of the data, how it is possible to determine the elastic and the Drucker–Prager constants for damaged borosilicate glass (or, in principle, any other brittle material). An important and unexpected result from these characterization tests is that the elastic properties of damaged glass do not change dramatically even if the glass is pulverized ( in situ comminuted). This is probably because the tests are highly confined and the glass has no space to move, and thus the elastic properties remain essentially unchanged. Estimates for the Drucker–Prager constitutive constants for in situ damaged borosilicate glass are also obtained. [ABSTRACT FROM AUTHOR]

Dynamic compression/shear experiments on a borosilicate glass at an average strain rate of 250 s−1 are conducted using a modified version of a split Hopkinson pressure bar. Instead of applying confining pressure, cuboid specimens with the material axis inclining to the loading direction at different angles (0°, 3°, 5°, and 7°) are used to generate higher shear stresses. A high-speed digital camera, synchronized with the loading stress pulse, is used to record the dynamic crack initiation and propagation. Experimental results show that the equivalent stress at failure decreases with increasing shear portion in the stress. Digital images show that the cracks initiate randomly in the right specimen, whereas cracks initiate from the stress-concentrated corners in the inclined specimens. Subsequent crack propagation, despite specimen inclination angles, is along the specimen axis rather than the compressive loading direction. [ABSTRACT FROM AUTHOR]

The formation of a plumbate network in binary lead silicate glasses was examined based on the leaching behavior of Pb2+ in lead silicate glasses over a wide composition region. The effective diffusion coefficient of Pb2+ at 40°C was on the order of 10−17 m2/s for PbO<35 mol% glasses, and increased three orders of magnitude for 35–50 mol% PbO contents. Such a steep composition dependence is considered to be because of changes in the medium or longer range structure. That is, it is proposed that the plumbate network forms a percolative 3D network in the composition region to form diffusion paths for the lead ions. In addition, the present results indicate that the lead ion exists as a network former over the entire glass forming composition range of the binary silicate glasses. [ABSTRACT FROM AUTHOR]

It is demonstrated that the density of binary glasses upon variation of the molar content of the modifier in their compositions obeys a parabolic dependence, whose parameters can be used to estimate the extent and type of reactions between the components. The reaction parameters in glasses that are prone to liquation are lower by an order of magnitude and have the negative sign. [ABSTRACT FROM AUTHOR]

Expressions for the interaction parameter as a function of macroscopic glass parameters are derived within the framework of a model taking into account the interaction between the structural elements in binary glasses. Analysis of published data established that the interaction index in alkali-silicate glasses within the temperature interval in which the temperature coefficients of expansions are constant does not depend on temperature. [ABSTRACT FROM AUTHOR]

The effect of the duration of treatment of the surface of soda-lime glass in potassium and lead nitrate melts at a temperature of 460°C on the chemical and mechanical strength is investigated. It is demonstrated that the formation of a crystalline lead-silicate coating in this treatment increases the alkali resistance threefold and the mechanical strength of glass twofold. Practical recommendations are issued. [ABSTRACT FROM AUTHOR]

The structure of multicomponent sodium-borosilicate glasses is investigated using the IR spectroscopy method, and their physicochemical properties are identified. It is demonstrated that enamels for protecting pipes used in the oil sector can be obtained on the basis of these glasses. [ABSTRACT FROM AUTHOR]