New effective moduli of isotropic viscoelastic composites. Part I. Theoretical justification

According to the approach based on the commonality of problems of determining effective moduli of composites and viscoelastic solids, which properties are time-inhomogeneous, it is assumed that a viscoelastic solid is a two-component composite. One component displays temporal properties defined by a pair of Castiglianian-type effective moduli, and the other is defined by a pair of Lagrangian-type effective moduli. The Voigt and Reuss averaging is performed for the obtained two-composite solid with the introduction of a time function of volume fraction. In order to determine closer estimates, a method of iterative transformation of time effective moduli is applied to the viscoelastic Voigt-Reuss model. The physical justification of the method is provided. As a result, new time effective moduli of the viscoelastic solid are obtained which give a closer estimate of temporal properties as compared to the known models

Algorithm of constructing hybrid effective modules for elastic isotropic composites

The algorithm of constructing of new effective elastic characteristics of two-component composites based on the superposition of the models of Reiss and Voigt, Hashin and Strikman, as well as models of the geometric average for effective modules. These effective characteristics are inside forks Voigt and Reiss. Additionally, the calculations of the stress-strain state of composite structures with new effective characteristics give more accurate prediction than classical models do

Thermal destruction of vessels with liquid upon heating

A new engineering technique of calculating the heating and thermal destruction of vessels containing liquid under extreme thermal loading conditions is offered. The heating of the shell and the internal vessel volume is described on the basis of the thermodynamic approach. The pressure growth in a vessel is a result of gas heating and liquid evaporation. Stresses within the shell and its destruction conditions are determined, which allows predicting the critical time of destruction upon heating. The calculation and experimental data for pressure growth inside the vessel are in good agreement

Algorithm of iterative transformation for effective modules of multicomponent isotropic composite

We consider the effective modules of Voigt, Reiss for isotropic elastic composites. We have reformed the method for constructing iterative transformation of the upper and lower estimates of fork (Voigt-Reuss) towards two-component composite in case of an arbitrary number of components. The method is based on the fact that effective modules of Voigt and Reuss can be regarded as elementary symmetric functions introduced by Gauss. The conditions, which the iteratively – transformed efficient modules must fulfill at every iteration, are shown

Algorithm of constructing hybrid effective modules for elastic isotropic composites

The algorithm of constructing of new effective elastic characteristics of two-component composites based on the superposition of the models of Reiss and Voigt, Hashin and Strikman, as well as models of the geometric average for effective modules. These effective characteristics are inside forks Voigt and Reiss. Additionally, the calculations of the stress-strain state of composite structures with new effective characteristics give more accurate prediction than classical models do

Thermal destruction of vessels with liquid upon heating

A new engineering technique of calculating the heating and thermal destruction of vessels containing liquid under extreme thermal loading conditions is offered. The heating of the shell and the internal vessel volume is described on the basis of the thermodynamic approach. The pressure growth in a vessel is a result of gas heating and liquid evaporation. Stresses within the shell and its destruction conditions are determined, which allows predicting the critical time of destruction upon heating. The calculation and experimental data for pressure growth inside the vessel are in good agreement

Determination of the heat-transfer coefficient and temperature of gas flow via measurement of the material temperature

A procedure based on the solution of the inverse problem of heat conduction is presented for the calculation of the heat-transfer coefficient and the temperature of a steady state gas flow via the measurement of the temperature of a material of a heat-insulated plate without numerical differentiation or the smoothing of experimental data. The sensitivity of the solution to a change in the convective heat-transfer parameters is analyzed. The measurement times at which the experimental data contain the maximal information on the sought parameters and the minimal influence of measurement error on their determination were determined. The application of the technique does not require the selection of a material-heating regime and makes it possible to increase the accuracy of the determination of the convective heat-transfer parameter

Thermal destruction of vessels with liquid upon heating

A new engineering technique of calculating the heating and thermal destruction of vessels containing liquid under extreme thermal loading conditions is offered. The heating of the shell and the internal vessel volume is described on the basis of the thermodynamic approach. The pressure growth in a vessel is a result of gas heating and liquid evaporation. Stresses within the shell and its destruction conditions are determined, which allows predicting the critical time of destruction upon heating. The calculation and experimental data for pressure growth inside the vessel are in good agreement