Volodymyr Mushchanov, Alexander Demidov, Anatoly Orzhekhovsky,
Serafym Fomenko, Anton Tanasoglo
The Convergence of the Elastic-Plastic State of a Cylindrical Shell by the Method of Elastic Solutions under the Action of a Distributed Load Along its Lines of Symmetry
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article presents a numerical calculation of an inelastic open cylindrical shell by the method of successive approximations based on the elastic solution method based on the previously developed technique [3]. The elasticity problem in each approximation is solved by the difference method based on the variational equation of J. Lagrange in the displacements of points on the middle surface. Moreover, the matrix of the system of equations does not change from approach to approximation. Only the right parts, which depend on plastic deformations, change. First, the statement of the problem is given: we consider a circular open cylindrical shell with pivotally fixed meridional edges and rigidly fixed edges in the circumferential direction under the action of a uniformly distributed load normal to the middle surface, acting along the lines of symmetry. The boundary conditions are formulated. The validity of using shell symmetry is proved. The convergence of the solution of the elastic problem by doubling the grid is established. The moment of appearance of the first plastic deformations in the most loaded node of the grid region is established. The definition of the magnitude of the effective load, to which the solution converges for a predetermined elasto-plastic state of a given shell by the method of elastic solutions, is given: the shear stress intensity field over the shell thickness over the entire grid region is given. The field of shear stress intensity over the entire grid area is presented in tabular form and in the form of volumetric-flat graphs. The influence of the choice of the number of points over the shell thickness when determining additional terms depending on plastic strains by the Simpson method is shown. It is proved that a significant refinement of the elastic-plastic solution for the VAT shell by this criterion is not achieved. It is shown that, taking into account plastic deformations, the percentage of stress reduction is less where, in the case of an elastic solution, the stress S is greater. A numerical experiment was carried out to determine the convergence of solutions of an elastoplastic stress-strain state in the most loaded node 2-34 with a grid of 27×35 nodes with five points along the shell thickness at
z = h / 2. The values of the load q, which correspond to the elastic solutions of the problem for the intensity of the tangential stresses S from the tensile diagram, are determined.
Keywords: closed inelastic cylindrical shell, Lagrange equations, boundary conditions, intensity of tangent stresses, Simpson method.
Рavel Solovej, Anatoly Perevarjuha, Kristina Sergeeva
Geodesic Monitoring of Chimneys in Restricted Observation Conditions
Donbas National Academy of Civil Engineering and Architecture
Abstract. Issues of geodetic monitoring of the vertical axis of the chimneys of industrial enterprises are considered, when a view to the structure is possible from one strong point, and in some cases there is no visibility to the forming structures. A method for determining the roll of chimneys from one stronghold using reflection less electronic total stations is proposed. The accuracy calculation of the proposed method is performed. It is established that the method provides the necessary measurement accuracy. In the absence of visibility to the forming structures, a method for determining the roll by coordinating at least 3 points located in the control horizontal sections is proposed, and the coordinates of the centers of the sections are obtained graphically in the AutoCAD system.
Keywords: geodetic monitoring, chimneys, cramped conditions, measurement error, measurement accuracy, construction roll.
Andrey Mironov, Yulia Ryb, Yulia Marchenkova, Anton Tanasoglo
Determining the Remaining Life of a Bridge Structure on the Donbas Highway
Donbas National Academy of Civil Engineering and Architecture
Abstract. Engineering calculation and estimation of the stress-strain state of the bearing elements of the superstructure is carried out. The analysis and collection of information on traffic intensity for 2019 was made. The history of loading a bridge structure with a real load is considered on the basis of a mathematical model (presented as a geometric progression) that shows the annual increase in traffic intensity along the bridge structure. The total fatigue damage of the bearing elements of the superstructure is determined according to the Palmgren-Miner hypothesis and the period of exhaustion of the operational resource of the bridge structure.
Keywords: load capacity, loading, history of loading, residual resource, the miner’s summation of fatigue durability.
Viktor Yarkin, Hanna Kukhar, Anastasia Anisimova, Vladislava Yarkina
Uneven Deformations of the Base of Buildings with a Steel Frame in Ground of the Fist Type Conditions by Subsidence
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article considers the influence of the way, area and intensity of soaking of collapsible soil on the amount of subsidence and their unevenness. The analysis of the most unfavorable for buildings schemes for the implementation of uneven base deformations caused by subsidence of the soil, both from the external load and from its own weight, was carried out and the conditions for their occurrence were determined. The influence of methods for subsidence accounting from the ground’s own weight when calculating buildings in ground conditions of the fist type by subsidence on their stress-strain state is studied. The conditions are determined under which in the design schemes of buildings and structures in ground conditions of the fist type by subsidence it is impractical to take into account possible subsidence caused by the own weight of the soil.
Keywords: collapsible soils, slumping soils, subsidence soils, loess soils, inundation, uneven deformations of the base, subsidence from dead weight, subsidence from external load.