ТООL SUPPLY THREAD IN PROCESSING TECHNOLOGY OF HIGHTEMPERATURE AND TITANIUM ALLOYS

Tap machining of high-temperature strength and titanium materials is considered

CALCULATION OF BUILDINGS WITH COMPLEX GEOMETRIC SHAPES FOR WITHSTANDING WIND IMPACT

Objectives. The possibility of modeling wind flow during the design of buildings with complex geometric shapes in order to determine comfort parameters and zones is considered.Methods. The investigation of the impact of wind on a cylindrical building was carried out using Ansys 15.0 software.Results. A finite element model of a modern art museum building having a complex geometric shape is developed for the calculation of the wind flow and the definition of comfort zones. The computational region is chosen such that its borders do not affect the calculation results. The maximum wind speed is assumed to be 44 m/s at an altitude of 10 m from the ground level, this being the maximum in the region of Novorossiysk. The topography of the earth's surface around the model was considered flat. The surface of the building was assumed to be smooth while the surface of the surrounding terrain was assumed to be rough with a roughness parameter of 0,1 m. The parameters of the building orientation relative to the wind rise were varied during the numerical modeling. Three variants of computational models with varying building location and its geometric characteristics are developed. In the first variant, the building model is stretched along the X-axis; in the second variant, the acute angle of the building model's contour is oriented along the Y-axis; in the third variant, the building model is located and oriented along the Y-axis with its obtuse angle of the external contour of the building. The calculation results of a cylindrical building for wind impact correspond to SP 20.13330.2011. The comfort parameters and zones of a building having complex geometric shape are defined by means of numerical modeling of the wind flow. The discrepancy between the object's normative characteristics and the research results is revealed during the calculation of the wind load.Conclusion. The recommendations are given for choosing the optimal location of the museum building, taking into account the comfort parameters and the greatest wind pressure; the geometric shape of the outer contour affects the location of the zones of reduced comfort; a sharp change in the boundaries of the outer contour leads to the appearance of increased pressure and wind speed and, as a consequence, a change in the direction of the vortex flows; it is necessary to apply the finite element method when modeling the wind impact for buildings of complex geometric shapes; sudden changes in the object's contour should be avoided when designing buildings and structures

CHANGE IN DEFORMATION PROPERTIES MODELING OF CONCRETE IN PROTECTIVE STRUCTURES OF NUCLEAR REACTOR BY IONIZING RADIATION

The necessity of studying the effect impact of elementary particles impact on the strength and deformation materials properties used in protective constructions nuclear reactors and reactor technology has been stipulated. A nuclear reactor pressure vessel from prestressed concrete, combining the functions of biological protection is to be considered. The neutron flux problem distribution in the pressure vessel of a nuclear reactor has been solved. The solution is made in axisymmetric with the finite element method using a flat triangular finite element. Computing has been conducted in Matlab package. The comparison with the results has been obtained using the finite difference method, as well as the graphs of changes under the influence of radiation exposure and the elastic modulus of concrete radiation deformations have been constructed. The proposed method allows to simulate changes in the deformation properties of concrete under the influence of neutron irradiation. Results of the study can be used in the calculation of stress-strain state of structures, taking into account indirect heterogeneity caused by the physical fields influence

Genome assembly of Vitis rotundifolia Michx. using third-generation sequencing (Oxford Nanopore Technologies)

The immune North American grapevine species Vitis rotundifolia Michaux (subgen. Muscadinia Planch.) is regarded as a potential donor of disease resistance genes, withstanding such dangerous diseases of grapes as powdery and downy mildews. The cultivar ‘Dixie’ is the only representative of this species preserved ex situ in Russia: it is maintained by the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in the orchards of its branch, Krymsk Experiment Breeding Station. Third-generation sequencing on the MinION platform was performed to obtain information on the primary structure of the cultivar’s genomic DNA, employing also the results of Illumina sequencing available in databases. A detailed description of the technique with modifications at various stages is presented, as it was used for grapevine genome sequencing and whole-genome sequence assembly. The modified technique included the main stages of the original protocol recommended by the MinION producer: 1) DNA extraction; 2) preparation of libraries for sequencing; 3) MinION sequencing and bioinformatic data processing; 4) de novo whole-genome sequence assembly using only MinION data or hybrid assembly (MinION+Illumina data); and 5) functional annotation of the whole-genome assembly. Stage 4 included not only de novo sequencing, but also the analysis of the available bioinformatic data, thus minimizing errors and increasing precision during the assembly of the studied genome. The DNA isolated from the leaves of cv. ‘Dixie’ was sequenced using two MinION flow cells (R9.4.1)

ABOUT DEVELOPMENT OF COMPLEX DECISION METHODS OF THE PROBLEMS OF DEFORMABLE SOLID BODY MECHANICS

From the setting of the problem in the transferences for possible cases of equivalent substitution of loads are formulated the necessary and sufficient condition of existence of analogy, allowing to represent the action of forced deformation in the form of sum of influence of surface and bulky forces, bulky forces in the form of sum of influence of surface forces and forced deformations, surface forces in the form of sum of forced deformations and bulky forces

DETERMINATION OF THE INITIAL CONDITIONS OF ROAD TRAFFIC ACCIDENTS IN THEIR CONSEQUENCES

Developed a calculation-experimental method of determining the initial conditions of road traffic accidents in their consequences in the event of a frontal collision

Stress state of the foundations of buildings and structures

Objective. Determination of the stress state of a ground base with a trapezoidal cutoff from the action of own weight, according to the conditions of equivalence of effects, is reduced to determining the stress state from the external surface load distributed according to the hydrostatic law. Methods. The problem of determining the stresses in the structure foundations at any degree of areas development of a plastic strain of the soil has a strict mathematical formulation, and similarity criteria can be obtained using a simpler construct of similarity theory. The simulation is performed by using similarity criteria based on which the model is executed, the loading conditions are determined, and the transition from the values measured on the model to the corresponding values of the full-scale structure is carried out. Similarity criteria can be obtained either with the help of similarity theory or with the help of dimensional analysis. An even greater effect of increasing the self-weight of a model made of transparent optically sensitive material can be achieved using the immersion method in conjunction with the centrifugal modeling method. If necessary, the stresses in the model area are fixed using the "freeze" method. Result. Using the equations system of the mixed problem of the elasticity and plasticity theory, and the scale method, similarity criteria are established for modeling stresses in the foundations of buildings and structures. Limitations on the choice of similarity multipliers for loose soils, the possibility of using the method of centrifugal modeling, as well as features of modeling connected soils are noted. Conclusion. A necessary condition for the similarity of the stress states of loose homogeneous bases in nature and the model is the equality of the similarity multipliers of the geometric scale and the force factor

PUNCHING CALCULATION OF REINFORCED CONCRETE FLOOR SLABS

Abstract. In this paper is considered the modeling of a monolithic reinforced concrete buildings structures by the spatial plate-core scheme and study of the floor slabs punching problem. When creating the finite element model of the building structure the floor slabs were created by four-node quadrilateral finite elements with 24 degrees of freedom, the columns and beams were created by spatial rods with 12 degrees of freedom. The calculation of the frame has been done by the software complex «SCAD», are got the efforts in the framework elements and are determined the concentration of stresses in the connections of slabs and columns. The program «Calculation of floor slab on punching» has been developed by the high-level language Object Pascal in Delphi environment, in accordance with the design standard which allows to research different locations of columns and stiffening diaphragms on the floor slab. The ratio of bearing capacity of the slab was calculated by means of the software «Calculation of floor slab on punching». Results are well correlated with the program «Arbat» of the software complex «SCAD». Difference of the developed program is in the possibility of considering of the columns and stiffness diaphragm location options on the floor slab (central, edge, corner). Program «Calculation of floor slab on punching» is recommended for use in the design of monolithic reinforced concrete structures

IMPLEMENTATION OF THE METHOD OF KINEMATIC DECOMPOSITION FOR CALCULATIONS IN NONLINEAR FORMULATION

Method kinematic decomposition in a physically non-linear formulation of solid mechanics computations of the screw piles AKSIS taking into account soil models based on the hypothesis marginal surface of the Mises - Schleicher - Botkin