Range of the Applicability of the Wilkins Method to the Investigation of the Dynamic Stress-Strain State of Anisotropic Elastic Axisymmetric Shells

The exactness and stability of the Wilkins method in the investigation of the stress-strain state of axisymmetric anisotropic elastic shells, including thick-walled ones, have been studied for different values of artificial viscosity, pulse load rise and fall time, and different deformation process durations. A comparison of numerical calculations, performed by means of an application software package developed by V. A. Romashchenko on the basis of the Wilkins method, with experimental results, known numerical data, and with calculations using the computation kernel LS-DYNA 3D has been carried out.     

Analytical Calculation of Large-Scale Deflection of Pulse-Loaded Elliptic Plates

Large deflections of pulse-loaded elliptic and round plates made of hardenable elastoplastic materials are investigated analytically using an energy-based approach. Formulas that are convenient for engineering design have been derived.     

Stress waves in the coupling zones of composite shells of revolution

The problem of the axisymmetric pulsed deformation of a composite shell of revolution and complex geometric shape is solved in the two-dimensional statement. The problem was solved numerically using the Wilkins explicit finite-difference scheme. The results obtained from the one-dimensional and two-dimensional theories, on the basis of which it is concluded that for ultrashort-term loadings with a duration of approximately 10^–1–10^–2 sec, the influence of stress risers is manifested only in the immediate proximity of points of abrupt change in the body's geometry (corner points), are compared. Here, the stress calculation must be performed in accordance with two-dimensional equations, since the onedimensional equations yield values on the low side in certain cases. In sections that are 1 mm and more distant from the corner points, it is possible to use the one-dimensional theory, since the error in stresses, which is obtained in this case, goes into the factor of safety.Institute of Strength Problems, Academy of Sciences of the Ukrainian SSR, Kiev. Moscow Institute of Thermotechnics. Translated from Problemy Prochnosti, No. 10, pp. 68–71, October 1989.     

A Criterion for Extractability of Mutual Information for a Triple of Strings

We say that the mutual information of a triple of binary strings a, b, c can be extracted if there exists a string d such that a, b, and c are independent given d, and d is simple conditional to each of the strings a, b, and c. It is proved that the mutual information between a, b, and c can be extracted if and only if the values of the conditional mutual informations I(a : b|c), I(a : c|b), and I(b : c|a) are negligible. The proof employs a non-Shannon-type information inequality (a generalization of the recently discovered Zhang–Yeung inequality).     

A numerical study of the nonlinear dynamics of multilayer spirally orthotropic cylinders

Based on the Wilkins two-dimensional algorithm, a method is developed for the numerical study of the geometrically and physically nonlinear axially symmetrical dynamic stress-strain state of multilayer thick-walled cylindrical elastoplastic shells with different spiral reinforcement structures. A numerical study of the specific features in the nonlinear dynamic behavior of single-and two-layer cylinders is carried out for different reinforcement configurations and loading amplitudes. Translated from Problemy Prochnosti, No. 6, pp. 110–121, November–December, 2008.