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Purpose. Solution of the three-dimensional nonlinear problem of external ballistics and development of an approximate mathematical model of the dynamic process for cargo falling from low-speed aircraft, which makes it possible to obtain an analytical solution, which is possible in combination with a geometric representation of the dynamic process using computer algebra. Methodology. Utilizing a blend of analytical and numerical research algorithms, an innovative model was devised, grounded in a nonlinear system of differential equations characterized by time-varying coefficients. The applied three-dimensional approach to the dynamic problem with an initial velocity from a UAV, in the presence of frontal and side wind loading, made it possible to use the nonlinear theory of external ballistics. This streamlining of the problem involved solving a related system of differential equations with variable coefficients along corresponding coordinates, leveraging an asymptotic approach. Furthermore, the formulation of the problem incorporated applied mathematical analysis and modeling, accommodating various pertinent environmental parameters. Findings. The creation of mathematical models and algorithms for calculating the parameters of the dynamic process of falling loads from low-speed aircraft within the framework of the theory of nonlinear external ballistics is an urgent problem both from the point of view of the development of the dynamic theory of the specified class of systems, and the creation of effective calculation algorithms with the possibility of practical application. As a result of the research, characteristic valuations of the influence of variable coefficients on the results of estimated accuracy of landing as a derivative of time were obtained. The obtained analytical and graphical dependences with the provision of appropriate assessments of the applied approach make it possible to establish the correlation of methods and results. Originality. The relevance of scientific research in the field of nonlinear external ballistics is based both on the internal trends of the development of this science and on the urgent needs of modern industry. In this paper, an approximate analytical solution of the nonlinear problem of external ballistics is proposed, which is subject to the applied conditions of motion. The resulting dependencies made it possible to establish the relationship between the parameters and find the degree of their influence on the landing time function. Practical value. The derived analytical findings and solution methodology can be integrated into practical applications within the realms of mathematical physics and engineering computations. This is particularly pertinent in the advancement of control algorithms for ballistic systems. [ABSTRACT FROM AUTHOR]

We analyze the estimate of the drag coefficient error obtained in aeroballistic experiment. Technical solutions, schemes, and devices for increasing the informative character of the experiment and reducing the error in the drag coefficient determination are proposed. [ABSTRACT FROM AUTHOR]

An analytic model is created describing the process of hitting thin targets. Mathematical expressions for determining the work for forming a stopper, for plastic expansion of the opening, work for friction and work done for heating are suggested. [ABSTRACT FROM AUTHOR]

This article deals with the perforation of ductile metal plates subjected to impact by flat-nosed projectiles at normal incidence. Generally speaking, ductile metal plates under impact by flat-ended missiles can fail either by global deformation combined with local shear rupture or by localized adiabatic shear plugging depending upon the geometrical and thermo-mechanical properties of both the targets and the projectiles. Modification is first made to the Bai-Johnson model for adiabatic shear plugging by taking account of strain rate effects using a thermo-viscoplastic constitutive equation instead of thermo-plastic material model and equations for the energy dissipated in the perforation process (perforation energy), the ballistic limit and the residual velocity are then obtained. Furthermore, a critical condition is obtained for differentiating localized adiabatic shear plugging from simple shear plugging failure with global deformations by comparing the modified Bai-Johnson model and the Wen-Jones model. It transpires that the present theoretical predictions are in good agreement with available experimental data in terms of the ballistic limits and the critical transition condition for the modes of plugging failure of ductile metal plates subjected to impact by flat-nosed missiles. It also transpires that the present model predicts well the residual velocities and the energies dissipated in the perforation process. [ABSTRACT FROM AUTHOR]

Mathematical expedients used in designing ground tests of aerodynamic object models with the aim of finding experimental conditions optimal in terms of the body and accuracy of extracted information are described. In the first part of this paper, the method used in designing ballistic experiment is demonstrated with processing of single-experiment data. In the second part, the validity of the design approach is illustrated by simultaneously processing trajectory data obtained in several experiments. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

The ballistic model of collisional absorption in the presence of an intense laser field is exposed and the resulting collision frequencies are shown to be in good agreement with those obtained from the dielectric model. Advantages in favor of the ballistic model and shortcomings of both are discussed. Misleading physical interpretations from the dielectric model are shown to have their origin in a partially inadequate mathematical treatment. [ABSTRACT FROM AUTHOR]