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A mathematical model for combustion of a propellant with a coolant taking into account the two-zone structure of the combustion front due to condensed- and gas-phase reactions was developed and examined. Formulas for the burning rate, reaction-zone temperature, and burning-rate sensitivity to internal and external parameters of the system were derived in analytical form. The burning rate was examined numerically as a function of pressure, the characteristic size of the system, component content, and thermodynamic and kinetic parameters. Recommendations are given on methods of obtaining particular ballistic properties by varying the initial parameters of the system.

The model of combustion of a composition consisting of a quasi-homogeneous composite propellant (matrix) and coolant particles is considered. The model is based on the leading role of exothermal decomposition of the matrix and on the cooling effect of the second component by virtue of transverse heat transfer between the components in the condensed and gas phases. Formulas for combustion characteristics (temperature, burning rate, its sensitivity to pressure, and initial temperature) are derived and analyzed. The calculated dependences of these characteristics on pressure, particle size, concentration, and thermal effects of decomposition of the components show that transitional regimes with a stronger dependence of the burning rate on pressure than that of the initial propellant are reached in a certain range of parameters. An algorithm is proposed, and a parametric identification of the model on the basis of experimental data is performed.

A method of construction of the effective strength surface of matrix composites based on the properties of their components taking into consideration the arbitrary anisotropy of the strength, elastic, and geometric parameters of these composites has been developed. The method is based on use of determinations of the first and second moments of the tensors of stresses in the components of composite materials.

We examine a microscopically inhomogeneous medium consisting of a homogeneous nonlinear viscoplastic matrix and a random set of rigid ellipsoidal inclusions of various sizes. A variant of the effective field method is used to calculate the macroscopic rheological constants of the medium.