No 3 (2011)

In the article, the methods of vibrations and dynamic stability analysis of bars having the nonlinear diagram deformation of material are suggested. The example of calculation of a bar with hinged supports of ends is given. The graphs of bar deflection as a function of time parameter are constructed.

Repeating failures and destructions of silo constructions are the result of inconsistency of existing methods of calculation. The present article gives the critical analysis of known calculated models of silo walls: flat system, system with the approached account of spatial work, spatial system of silo covers on V. Vlasov 's method. Authors mark necessity of further experimentally-theoretical researches of distribution of loading for silos, and also the account in calculations of variability of loadings and spatial work of walls of a silo by means of modern systems of computer modeling.

In article, it is investigated mechanisms of formation of a tense-deformed condition of elements of a framing of multi-storey buildings, at local damage of one of vertical load-carrying structures. Researches are spent both in static, and in dynamic statements of destruction of a load-carrying structure.

On the basis of a curvilinear quadrilated finite element the new mode of approximation of fields of displacements is realized, which essence consists that at a stage of approximation of interior magnitudes through nodal unknown of a finite element accept not separate components of a vector of displacement and their derivative, and immediately vector of displacement of nodal points of a finite element and its derivative. On an example of account of an equalizer loaded by interior pressure with presence of constructional displacement as rigid body is shown. That use of the developed algorithm solves a well-known problem FEM - account of displacement of finite element as rigid body.

Using two natural lateral axisymmetric flexural vibration frequencies, we can determine both radius and thickness of the plate thinned central part.

Constructive variants of composite armature and variants of manufacturing techniques of the compound composite armature are considered. ASTROFLEX rebar is a composition of an external layer of patented carbon-based nanocomposite material PRECIZER and an internal core of another patented nanocomposite Nanconcrete Light (nanocomposite armature patent claim -"ASTROFLEX", PCT/RU2010/000290). ASTROFLEX rebar offer the following features: corrosion firmness, durability, high adhesion to concrete, a high operational resource, high resistance to the sign-variable loadings, the raised fire resistance and the comprehensible cost price. The basic directions of using ASTROFLEX rebar in hydraulic engineering building and in a bridge building are analyzing.