No 4 (2010)

The closed cylindrical shell finite length under the action of constant at time and alternating local transversal loads in the context of nonlinear classical theory of gentle shells is consider. The equations in partial derivative are reduce to the combined of ordinary differential equation at times (the problem Koshi) using Bubnov-Galerkin's method as a higher approximation in Vlasov's form. The combined of ordinary differential equations is solved Runge-Kutt's method of the fourth order. The convergence of Bubnov-Galerkin's method is analyzes. The dynamical critical loads under the action unlimited impulse at time for conservative system (ε = 0) and alternating transversal load for dissipative system (ε = 1) in depending on quantity of members expansion series are finding

Efficiency of drilling remains at catastrophic deterioration of arms roller bits. This phenomenon is not entered in existing theories of destruction which reject possibility of formation of the main crack in parallel a semispace plane. Presumably it is formed at high-speed unloading of the rock loaded within elastic deformations

For the calculation of developments in conditions of flat problem of theory of jump is designed matrix an deforming tetragonal end element on the count of physical material uneven line in base deformation theories of plasticity. On the measure that as a node unknown finite element were taken incriminations of displacing and incriminations of voltages. Incriminations of voltages and moving an internal spot of end element were approximated through node values of sought values by correlations of two linear sought values.

A stability problem for an elastic structure subjected to conservative and active forces is considered. The structure has unilateral constraints and initial imperfections. An example of a system with two degrees of freedom shows that in general case, the analysis of stable states of such structures may be performed only on the basis of a non-linearized problem of stability.

In the article results of calculation of a critical load for system «a construction - a base plate - a layer of the basis » are considered within the limits of a flat problem. The model of system uniting absolutely rigid construction on a deformable base plate, cooperating with physically nonlinear layer of the basis is shown, allowing to reduce a problem of stability of a construction to a problem about own values

The plane problem of mechanics of fracture cracks cracks-stratification, arising at the interface of road covering coupled with the elastic basis of another material, when the wheel is pressed into the road surface under the influence of an arbitrary system of forces is considered.

The estimation of the technical state load-bearing structures is given, the value of losses of bearing capacity after fire was determined. progressing the character of local damages from action of non-stationary high-temperature condition is mounted. Recommendations for building intensification are developed for its further safe operation