Simulation Of Stress-strain State Research Articles

Technical diagnostics of heembedded elements of crane tracks of lifting equipment in machine halls of tunnel escalators

BACKGROUND: During the operation of crane beams of lifting equipment of subway tunnel escalators machine halls, the information about the technical condition of certain structural elements of supporting metal framework is always relevant, which determines the possibility of their further safe use and the need for repair and restoration work. The value of the remained service life is estimated by comparing the actual load-carrying ability with the criteria corresponding to the limiting conditions according to the project documentation. The actual state of the supporting framework elements can change with time significantly, therefore, the assessment of the remained service life is carried out with an experiment-and-simulation method based on the determination of stresses and their maximum deviations in weakest sections of framework elements with the determination of the degree of their impact on durability in the long term.
 AIMS: Analysis of the combined application of methods for modeling the stress-strain state with subsequent wavelet analysis of wave processes in the interlocked stud-bolts of the suspension unit of riding beams of lifting and transport equipment of subway tunnel escalators machine halls.
 METHODS: With regard to the specific features of the design, numerical simulation of the technical state of the interlocked sections of the stud-bolted suspension of crane beams of lifting equipment of subway tunnel escalators machine halls is considered in this work. The capabilities of the Simulation (static analysis using the finite element method) and Motion (kinematic and dynamic research with formation of systems of differential equations of motion and subsequent solving) modules of the SolidWorks software platform were used in the development of the model.
 RESULTS: As a result of the carried out research, with regard to the specific features of various methods of the stress-strain state simulation, a spatial linear dynamic model has been developed that reflects the processes occurring during the deformation of the stud-bolt suspension of the supporting I-beam, which is helpful for an objective assessment of its technical state, as well as the possibility and conditions of further operation.
 CONCLUSIONS: To simulate the stress-strain state, the combined application of methods is necessary, followed by a wavelet analysis of wave processes, which increases the reliability of diagnostic procedures and, consequently, makes it possible to make reasonable decisions about the further operation of the facility.

Моделирование напряженно-деформированного состояния одноэтажного каркасного здания, получившего повреждения

Purpose: Stress-strain state simulation of the one-story prefabricated reinforced concrete building on a monolithic foundation slab damaged after instrument-aided structural survey, including damage to the self-bearing brickwork caused by earlier earthquakes. This frame building is constructed without consideration of seismic impacts. Methodology: Engineering-geological survey, structural analysis, finite element modeling in the MicroFe software, development of the base– foundation–building model. Practical implications: The obtained results are used to provide the reliability of the frame building by implementing technical solutions on restoration of its serviceability in seismic conditions

Stress-strain state simulation of non-uniformly heated elements of components and assemblies of automotive

Develop a method for determining and evaluating the stress-strain state, particularly the distribution of thermomechanical stresses in the materials of individual rotating parts of vehicles.The proposed method is based on the principle of gradual approximations of the solution when the boundary conditions are satisfied on the curvilinear limiting surfaces of the disk body.The proposed method of determining and estimating the distribution of thermomechanical stresses in the disk material makes it possible to take into account the variable geometry: thickness and presence of a hole in the central part of the disk, also correctly determine stress-strain state at any point of unevenly heated rotating axial body.The work uses generally accepted assumptions and limitations for thermomechanical calculations.It is proved that in real disks, the stress-strain state is spatial, and the well - known method based on the hypotheses of the plane-stress state does not provide the possibility of calculating the values of stresses in the thickness of the disk. The obtained results can be used to improve the methodology of auto technical examination of road accidents. In addition, they can be taken into account by bus drivers on urban routes when choosing a safe distance in heavy traffic, as well as design engineers of car brake systems.

Determination of Thermomechanical Stresses in Elements of Vehicles' Braking Systems

The main objective of the study was to develop a model and analyze the thermomechanical behavior of the hub material of the vehicle brake disk. The simulation strategy was based on the solution of the three-dimensional problem of the theory of elasticity for the case of effect of external loads and temperature fields on the metal structure element of the vehicle brakes. To solve this type of task of the theory of elasticity, the differential equations of the second order were used for the first time. Adaptation of the proposed model, completed in the article, has proved the correctness of use of these equations in modeling the thermomechanical processes with determination of stresses and displacements in unevenly heated rotary cylinders of the final length. The proposed method can be applied with high efficiency in stress strain state simulation of individual parts of vehicles.

Моделирование напряженно-деформированного состояния земной коры о. Сахалин: влияние гидроизостазии

The paper attempts to answer the question about the role of contribution of the hydroisostasy to the stress-strain state of the Earth’s crust on the Island of Sakhalin. The hydroisostasy contribution was estimated by simulation by means of finite element method. The mesh grid for the calculation was constructed using the real values of the depth of the Moho discontinuity surface and the topography of Sakhalin Island with adjacent shelf areas. The calculation took into account the Central Sakhalin fault zone. Lateral displacements as a result of strain and lateral displacements combined with vertical ones were simulated separately. Comparison of the results of the stress-strain state simulation, taking lateral displacements and their combination with vertical ones into account, clearly demonstrates the significance of the hydroisostasy contribution to the stress-strain state of the Earth’s crust in the Sakhalin region.

ANALYSIS OF STRESS STATE OF SPHERICAL JOINT OF TRIPOD HEADS WITH VARIOUS FIXATION METHODS

The results of simulation of stress-strain state of various design solutions of spherical hinge of the tripod head for installation and positioning of measuring, video and photo-fixing equipment are considered. There are presented comparisons of hinge loading in different methods of fixation. Comparisons of hinge pin loading at fixation with fixing screw and pressing washer are given. Recommendations on design and design selection taking into account the peculiarities of the work are justified.

Simulation of stress-strain state of resistance spot welded joints in NX environment

The paper considers the study of the condition of resistance spot welded joints using their digital prototyping and the Finite Element Method (FEM). Numerical simulation of welded joints and the study of their stress-strain state were performed in the NX software environment. The obtained results fully coincide with the data on the destruction of real welded joints. The proposed simulation method and calculation technique can be recommended to design engineers for practical purposes.

Computer simulation of stress strain state of functionally graded sandwich plates and shallow shells of the complex shape resting on elastic foundation

Computer simulation of stress strain state of functionally graded sandwich plates and shallow shells of the complex shape resting on elastic foundation

COMPARATIVE ANALYSIS OF STRESS DISTRIBUTION IN ELEMENTS OF DIFFERENT DESIGN OF HINGE JOINT OF SPHERICAL MECHANISM

Results of simulation of stress-strain state of various design solutions of hinge of spherical converting mechanism for stepless drives are considered. Comparisons of hinge loading are given when using an intermediate bushing made of various materials and without it. Recommendations for designing such an element taking into account the peculiarities of the work are justified.

Simulation of stress-strain state of corrugated cardboard in flexographic printing and its influence on imprints quality

Simulation of stress-strain state of corrugated cardboard in flexographic printing and its influence on imprints quality

Impact of “wet conservation” of mining enterprises on constructing buildings of lightweight materials

The analysis of the influence of flooding of the developed areas of closed mining enterprises on the mechanical characteristics of clay rocks is given. The deformation characteristics of clay shale under prolonged moistening conditions have been experimentally established and proved. Simulation of stress-strain state of soil massifs and building structures by method of finite elements is considered and the influence of power of developed spaces on settlement of building foundations of buildings of light materials is established. The distribution of vertical displacements in the rock massif is presented, the graphs of the dependence of the foundation settlement on the excavation power are plotted, the excess of the standard values of settlement is noted when buildings are located directly above the preparing workings.

Numerical simulation of stress-strain state in frozen wall during thawing

Blasting and drilling operations during shaft sinking assume switching off the freezing columns which can lead to stability loss of a frozen wall and inrush of thawed soil into the stope. This work assesses safety of shaft sinking when freezing columns are turned off for a period of four days. It is assumed that the frozen wall loses its bearing capacity when displacement of its unfixed section exceeds 10 cm. Calculations are carried out for silt and sand stratums. Simulation was performed in finite-element software Comsol Multiphysics. Displacements of internal wall were obtained for two initial thicknesses of the frozen wall. In the first case the soil was frozen to the boundary of the future shaft, in the second case initial thickness corresponded to project documentation. It has been shown that frozen wall in silt stratum does not lose its bearing capacity even for complete defrosting. For sand stratum calculated time was equal to 85 days for the first thickness and 24 days for the second thickness of frozen wall.

The stress-strain state simulation for the auger-boring machine’s support-guide system

The article deals with a number of important aspects of the aggregate-modular type auger-boring equipment creation, as an integral part of the range of tunneling complexes for mining operations and laying horizontal and slightly deviated holes for various purposes. The importance of improving the support and guide systems, characterized by a variety of configurations and sizes, a large number of elements for various purposes and with different responsibility degree, is noted separately. In this regard, the possibility of flexible refinement of the complexes configuration for specific boring conditions with the verification of each applied technical solution by computer modeling remains relevant. The ways for a new constructive solutions creating are outlined.

Simulation of stress-strain state of basalt concrete beams

Simulation of stress-strain state of basalt concrete beams

ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ УСТОЙЧИВОСТИ БОРТОВ УГОЛЬНЫХ РАЗРЕЗОВ ПОД ДЕЙСТВИЕМ РАСПРЕДЕЛЕННЫХ НАГРУЗОК

The open method of solid minerals winning occupies a significant place in the total opening of the mining complex deposits of the Republic of Kazakhstan. In the energy band, a prominent role belongs to the Ekibastuz coal basin, where a number of large coal strip mine operates. The level of subsurface, equal parts of spoil bank of the external and internal stripping after a while lead to complex problems of ensuring the stability and safety of mining operations. The location of large external rock dumps on the bead surface has a negative effect on the stability of the latter. The purpose of the work was to establish the degree of the external rock dump influence located on the bead surface on the stability of adjacent rock mass of the coalmine depending on the distance of the dump to the upper edge of the side. There was numerical simulation of stress-strain state of adjacent rock mass under action of distributed load from rock dump carried out. It has been shown that studies of any point stability of the array from this type of load should be carried out on the basis of elasticity and the use of the finite element method theory implemented in packages of programs oriented specifically to scientific and engineering applications. There are the methodology and results of numerical modeling of quantitative assessments of various sections stability of the side loaded with an external rock dump with a height of 160m presented on the example of «Ekibastuz» coal mine. Based on a certain theory of rock strength and the criteria for their discontinuity, limit estimates of the critical distance of the external rock dump from the upper edge of the side were obtained, at which the latter may lose stability.

GEOMECHANICAL MODELING IN MINING AT THE ELGINSKY DEPOSIT

Using the Elginsky coal deposit as an example, the relevance of building digital models of geological objects to control the geomechanical condition of open-pit walls is shown. Physico-mechanical properties of overburden rocks are given. The results of numerical simulation of stress-strain state of the rock mass are presented. The directions of general stress displacements and zones of maximum displacements of the open-pit wall are determined and the maps of their distribution are compiled. It is shown that lower benches are more susceptible to tension.

Modeling the stress-strain state of of a municipal solid waste landfill

Introduction. The process of municipal solid waste (further MSW) generation is inextricably linked with the life of humanity. Every day each person generates some, a small amount of garbage. As a result millions of tons of MSW are generated daily in the world which are unsuitable for further use and require disposal. There are various ways of handling MSW including their treatment, recycling and disposal. In Russian Federation the vast majority of MSW are currently located on the specially equipped facilities –– waste landfills. To date the most common waste management strategy remains their placement in a landfill. Waste landfills are arrays of stored waste and are special engineering structures designed for the safe isolation of their contents from the environment. Landfill includes gas exhaust and leachate drainage systems, liner and cover systems. The main component of this structure is waste itself. Mechanical stability of landfills should be provided at all stages of waste storage as well as after it complete filling to designed capacity and at post-closure stage. As the result of deformation of unstable waste, all landfill systems can be destroyed up to the collapse of garbage array leading to the significant environmental and other consequences. One of the most common problems leading to the various incidents at landfills is an incorrect assessment of their stability. MSW landfill is a complex multiphase system in which various interacting processes occur simultaneously. The main factor in the calculation and design of landfills is the forecast of their settlements. Studies by many authors have established that biological decomposition has a significant impact on the properties of MSW after which the waste is considered as the landfill soil with a particle size of up to 20 mm. Materials and methods. The paper presents the methodology and the results of numerical modeling of stress-strain state of the designed object “Waste Landfill”. The facility is an array of municipal solid waste of 38 meters high. Waste is stacked in the layers of 1.75 m thick. Each waste layer is covered by the loam cover of 0.25 m thick. Stress-strain state of municipal solid waste including biological creep was modelled using well-known “Soft-Soil-Creep model” (SSC-model). Results. The results of numerical simulation of stress-strain state of the waste pile at all stages of the filling and in the post-closure period are presented. An assessment of the increase in the capacity of the landfill due to the compaction and biological creep has been performed. Stability analysis of the landfill and potential failure mechanisms at different stages of filling and operation are presented. Conclusions. Numerical modeling of stress-strain state of the MSW array using the “Soft-Soil-Creep model” allows to analyze the stability of the waste pile at any stage of landfill filling and evaluate the increase in landfill capacity due to the waste settlement taking into account the mechanical creep and biocompression during layer-by-layer filling.

STUDY OF THE INFLUENCE OF SECOND ORDER EFFECTS ON THE EXAMPLE OF THE STEEL FRAME OF THE AIRPORT

With the help of modern licensed BIM-information systems of PC Dlubal RSTAB and PC Dlubal RFEM, simulation of stress-strain state and cross-section selection of complex spatial steel structures of the airport, located in Frankfurt am Main (Germany), based on theories 1st and 2nd order effects according to standard DIN EN 1993-1-1-2010 were performed. Spatial steel structures of the airport located in Frankfurt am Main, have been adopted as the object of study. The prototype is the Chennai Airport (India), an architectural concept developed by the American company Frederic Schwartz Architects. The main bearing structures are adopted in the form of spatial steel trusses of complex shape. To determine the cross-sectional dimensions and spacing of the spatial trusses, preliminary calculations were performed. Finally, the step of the spacious trusses was 9 m. The collection of self-weight and imposed loads is carried out in accordance with DIN EN 1991-1-1. The collection of wind loads acting on a complex geometric shape was performed using a virtual wind tunnel and accelerograms, using a CFD analysis of the Dlubal RWIND Simulation PC. To perform CFD analysis, the Dlubal RSTAB PC model was exported to the Dlubal RFEM PC, which made it possible to take into account the presence of external enclosures, overlapping elements and cover, modeled using zero plates, when modeling wind flows. After setting the basic calculation parameters, the model was generated and exported to the Dlubal RWIND Simulation PC. Wind flow simulation in Dlubal RWIND Simulation PC, performed for eight wind directions, of which four most unfavorable were transferred to Dlubal RSTAB PC as separate downloads for further calculation. According to the results of the comparison of the coefficients of the cross-sectional area, it is found that taking into account the effects of the second order, depending on the type of design considered, may lead to the need to increase the estimated cross-sectional area in the range from 22 to 42%. Thus, for complex spatial steel structures, the provisions of the Eurocode standards are confirmed, according to which the consideration of 2nd order effects is obligatory for consideration.

Simulation of stress-strain state at the boundaries of a bimetallic composite to determine tear-off resistance

Simulation modeling of the deformation under mechanical action on the sample workpiece of the steel-aluminum bimetallic composite material with a thin aluminum intermediate layer was performed. The stress-strain state along the boundaries of the joint at which the sample workpiece layering occurs was determined. A series of computational experiments with varying the specific work value of the layering under separation conditions was implemented. The level of stresses, leading to the separation of the bimetallic compound, is estimated using the energy criterion. The dependence of the rupture strength along the ring contour on the specific work value of the layering varied in the range of 0.1-0.2 N/mm was calculated. It was established that for the studied variants of the computational experiment, a rigid stress state with the predominance of normal tensile stresses is implemented in place of the beginning of the layering.

Применение метода декомпозиции области для решения задачи контактного взаимодействия осесимметричных тел

Several variants of domain decomposition method are presented, including overlapping methods (multiplicative and additive Schwarz methods) and nonoverlapping methods (Neumann-Dirichlet and Neumann - Neumann). The results of their application for solving the two-dimensional problem of loading a section of an elastic pipe with pressure are considered. The dependence of the number of external iterations on the grid step and on the number of subdomains has been investigated. It has been shown that the best results are obtained for the two-level Schwarz additive method. This method is generalized to the case of solving the problem with the contact of the column of the body. To take into account the contact between the bodies when solving the local problem in each subdomain, the Neumann -Dirichlet method is used. Results of application of two-level Schwarz additive method for numerical simulation of stress-strain state of fuel element section are presented.