scholarly journals Statistical analysis of stress-strain state of bearing jaw crusher

2020 ◽  
Vol 1 (2) ◽  
pp. 159-171
Author(s):  
Yuliya Andreevna LAGUNOVA ◽  
◽  
Stanislav Anatol’evich MAYOROV ◽  
Gennadiy Alexeevich BOYARSKIH ◽  
◽  
...  

The relevance of the work. When creating particularly large machines and systems, in the case of their 3D modeling and detailed study, the load on the central processor of the computer, as well as on the graphic and RAM modules, increases, which significantly slows down the design process and calculations. In the article, a statistical analysis of the stress-strain state of the jaw crusher bearing is carried out to establish the correspondence of the theoretical and actual structural models taking into account all workloads. The objectives of the study. Consider the task of selecting a simpler and “easier” for the calculation model programs, not difficult to parameterize, compared with the original bearing model, but providing accuracy in the calculation in an acceptable range of errors. To analyze the stress-strain state of the bearing assembly with various geometric parameters. Research methodology. In the calculations, the finite element method was used. Used specialized software package APM WinMachine. A computational experiment was conducted. A correlation analysis of the theoretical and actual structural model of the bearing is carried out. Results. Mathematical models of the metal structures of bearings of various sections are given and the locations of the highest stresses are identified. Calculation errors and correlation dependencies of stresses are established taking into account the Pearson, Fisher criteria and the construction of the Taylor series. Conclusions. The results of a computational experiment satisfy the requirements and can be used to solve further problems of designing bearing assemblies. In the future, a parameter-dependent model can be created that makes it easier to calculate using any type of bearing

Author(s):  
Stanislav Maiorov ◽  
◽  
Iuliia Lagunova ◽  

Introduction. The article considers the calculation of the strength of a bearing mounted on the connecting rod of a jaw crusher, taking into account all workloads. ISSN 0536-1028 «Известия вузов. Горный журнал», № 3, 2020 117 Object problems. When creating particularly large machines and systems, in the case of their 3D-modeling and detailed study, we are faced with an increased load on the central processor of the computer, as well as on the graphics and RAM modules, which leads to a significant slowdown in the design process and calculations particular. Research aim is to consider the task of selecting a simpler and "easier" for the calculation model programs, not difficult to parameterize, compared with the original bearing model, but providing accuracy in the calculation in an acceptable range of errors. The research also aims to analyze the stress-strain state of the bearing assembly. The main methods. In the calculations, the finite element method was used. Specialized software package APM WinMachine was also used. Computing experiment conducted. Conclusions. The results of a computational experiment satisfy the requirements and can be used to solve further problems of designing bearing assemblies. In the future, a parameter-dependent model can be created to facilitate the calculation using any type of bearing


2019 ◽  
Vol 265 ◽  
pp. 04015 ◽  
Author(s):  
Tokhirjon Sultanov ◽  
Bakhtiyor Yuldoshev ◽  
Elyor Toshmatov ◽  
Javlonbek Yarashov ◽  
Rustam Ergashev ◽  
...  

A comparative method for estimating the stress-strain state of earth dams under the effect of static load is given in the paper using spatial and plane-strain models. The results of assessment of stress-strain state of several earth dams using these methods are given. Analysis of the results obtained allows us to conclude that a plane calculation model gives results almost identical to the ones obtained with spatial model; in future that can be the basis for developing recommendations on the use of certain calculation models. Some features of stress state in a spatial case are revealed, indicating the occurrence of dangerous areas with the greatest stresses.


Author(s):  
Elvira R. Kuzhakhmetova

Relevance. The underground part of the building (foundation and soil) has a significant impact on its stress-strain state and behavior under the influence of operational loads. Therefore, the existing regulatory and technical documentation regulates the design of buildings (structures), taking into account the joint work of their aboveground and underground parts. In practice, such accounting becomes possible on the basis of a comprehensive engineering analysis of the building as a large mechanical system building - foundation - soil, which today can be carried out using the finite element method. In the case of pile foundations, the correctness of the result depends largely on the reasonable choice of the design model of the pile-soil subsystem. The article analyzes three design models of piles operating in an array of soil foundation. The first model is discrete. In it, the pile is modeled by bars and is based on elastic supports (Spring) with generalized stiffnesses. Second model - spatial, in which the pile and soil are typed in by volumetric elements (Solid). Third model - spatial-bar or combined, in which the bar pile is embedded in the mesh of the soil mass using a rigid substructure formed by bars of high rigidity. The aim of the work - to determine a rational calculation model of the pile - soil subsystem, which allows, on the one hand, to reduce the general order of the system of resolving equations, and, on the other hand, to maintain the accuracy of the assessment of the stress-strain state of the calculation model of pile - soil and the building as a whole. Materials and methods. The numerical results of the analysis of the pile foundation statics using the three pile - soil calculation models were performed in the CAE software package - the Femap with NX Nastran class, which implements the finite element method. Results. Comparative-numerical analysis of the stress-strain state of the pile foundation - soil subsystem made it possible to determine the advantages, disadvantages, and also the areas of rational use of bar, spatial combined calculation models. In the next articles, it is planned to consider the calculation of piles for vertical loads, as well as a comparative analysis of numerical results with experimental data (in the labo-ratory or in field conditions) for horizontal and vertical effects.


2021 ◽  
Vol 20 (3) ◽  
pp. 259-267
Author(s):  
N. S. Sivtsev ◽  
V. V. Tarasov

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as  as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.


2010 ◽  
Vol 2 (3) ◽  
pp. 106-117 ◽  
Author(s):  
Michail Samofalov ◽  
Miroslav Janovič ◽  
Kęstutis Tumosa

A calculation model of a building is only a simulation of the individual properties of the construction. Such a model is expressed by many factors, the most important of which are experience and knowledge of a designer. In difference to a traditional “single-stage” solution, an effective numerical analysis of a complicated situation can be presented comparing a few different variants. Such situation is specific for high-technology industrial facilities or entertainment buildings. A typical simulation sequence cannot be used for original buildings with principally different properties because investigation should take into account features of the construction. A general solution should analyze the already existing technical possibility and an individual situation considering the qualification of engineering staff. The paper presents investigation into a transversal frame of an indoor slope of the complex facility “Ski Slopes Covered With Snow Pavement in Druskininkai, Lithuania” carried out in 2009. According to the current Eurocodes and Lithuanian design codes, the service life of the facility is 100 years and a class of responsibility is RC3. The frame has a bay of 51,5 m, columns with foundations and a truss are rigidly jointed, the middle height of the frame (depending on the angle of the slope along facility) is about 1/3 of the bay. The stiffness of all structural members is specified. For frame actions and structural design, valid design codes are used. In geomorphologic meaning, the building site is placed near (about 100 m) the river Nemunas where real difference in the altitudes of the ground initial surface makes about 40 m. On the basis of the analyzed situation in the site, a decision on making a foundation with a pile cap on displacement piles has been accepted. Each pile consists of two parts: the upper part is of 600 mm diameter and 2 m length, whereas the last one has a diameter of 380 mm. After pile mounting, the steel shell of the pipe is pulled out. For an analytical analysis of a single pile, the Vesic formula is applied. Under conditions that two piles of the building site have been tested by means of vertical load action, two pairs of piles have followed the horizontal one. Vertical 1044 kN and horizontal 120 kN test loadings have been divided into 6 equal stages. Two asymmetrical foundations of the transversal frame are designed differently and make 8 piles in axis “A” and 6 piles - in “E”. Three variants of the pile calculation model are considered: node support, one finite element (an upper part of the pile) on the elastic spring in the vertical direction at the bottom edge and a pile divided into two parts on the vertical elastic spring at the bottom edge and along it (a horizontal subgrade factor). Within a course of investigation, the pile cap is modelled applying shell finite elements while the piles - employing beam ones. The final decision about frame stress/strain state can be made on the basis of analyzing the general calculation model “over-ground frame/foundation/ground”. Thus, three new models, including 5, 6 and 7 present foundations are jointed by the over-ground frame. In these cases, the columns with the truss are subjected not only to static loads but also to kinematic actions, i. e. foundation settlements, rotations and lateral displacements. A comparison of the results of seven separate calculation models shows that support parts of the columns are loaded low in case of elastic subgrade on the piles; bending the pile cap is the same; the distribution of internal forces between foundations in case of piles is more “soft”. Conclusions and recommendations are provided.


Author(s):  
Diana Popova ◽  
◽  
Nikita Samoylenko ◽  
Sergey Semenov ◽  
Viacheslav Shisterov ◽  
...  

The main problem of using roller bearings with direct forming rolling elements in highly loaded units is the edge effect. A significant increase of stresses at the edges of the rolling elements is the cause of the fragility of highly loaded roller bearings, which is a significant problem, especially in such units as rotors of aircraft engines. The solution of this problem in aviation is the use of rolling elements with a modified contact - bombed rollers. This paper presents comparisons of the stress-strain state of contacts of pairs of bodies imitating bombarded rollers of various geometries. The calculation was performed by the finite element method in the ANSYS package. For the calculation, the contact of the roller with a flat plate was used. In the calculation, the stress-strain state of the roller with the direct forming, the roller with the rounding of the face and the bombed rollers with various shapes of the modified forming was evaluated. The calculation model is verified with respect to the classical Hertz formula. The dependence of stresses in the concentration zone on the relative dimensions of the bombarded part of the roller with a standard generator representing an arc of a circle is estimated. A form of the generatrix is proposed, which more effectively reduces stresses in the transition zone of the modified generatrix into the straight line. The proposed form of the generatrix eliminates the main drawback of the classical generatrix of the bombarded rollers - the appearance of a concentration zone in the transition region of the straight part of the roller to the bombed, thus providing a better stress distribution in the roller. The technique used to simulate the contact interaction of rolling elements in a roller bearing can be used to study the stress-strain state of roller bearings of a different geometry, including those used in modern gas turbine engines.


2020 ◽  
pp. 64-71
Author(s):  
Iryna Zhupanenko

Despite significant progress in the development of methods for calculating the soil base in a single calculation model with structures and the ability to perform calculations in three dimensions, the most popular in the community of design engineers remains the calculation model of the slab on an elastic basis. This is due to the simplicity of such a model. Probably, the greatest difficulty in applying such a model is to determine the coefficients of flexibility of the base (bed coefficients). In this paper, a study of the reliability of different methods for determining the coefficients of the bed under different variants of soil conditions The paper determines and compares the characteristics of the stress-strain state (sedimentation values, reactive pressure and forces) in three foundation slabs of different geometry and under different engineering and geological conditions of the construction site. A homogeneous base composed of loess soils, an inhomogeneous base composed of alternating layers of both cohesive (loam and sand) and incoherent (fine sand) soils and a close to homogeneous base composed of sand and soils are considered. The research was conducted using the software and computer system LIRA SAPR 2016. Implemented three methods for determining the coefficients of the bed (the flexibility of the base): - Pasternak model with two bed coefficients, which for inhomogeneous soils are determined by the values of the deformation modulus and Poisson's ratio averaged within the depth of the compressible thickness; - Winkler model with one bed ratio; - Pasternak model with two bed coefficients, which are determined by the average values of the deformation modulus and Poisson's ratio when introducing the correction factor to the deformation modulus. The convergence of the absolute values of the controlled parameters obtained using the above methods, depending on the type of soil base and the nature of soil layers within the compressible layer, is analyzed. The dependence of the convergence of the characteristics of the stress-strain state of the slab obtained by different methods on the homogeneity of the base soils is established.  


2019 ◽  
Vol 970 ◽  
pp. 47-54
Author(s):  
Petr Khorsov ◽  
Roman Laas ◽  
Anatoly P. Surzhikov

The paper assesses the possibility of using the reverberation phenomenon to control the imperfections and the stress-strain state of solid dielectric materials by the method of mechanoelectrical transformations. The main advantage of reverberation is the repeated intersections of the excitation zones of inhomogeneities by acoustic waves, that is displayed in response parameters. The reverberation makes it possible to accumulate distortions of wave fronts. A comparative analysis of the responses from the sample under condition of uniaxial compression under different loads was performed. Differential analysis for the deterministic time component of the response in the interval (0–0.3) ms, and a statistical analysis of the differences for the pseudo-random component in the interval (0.8–1.8) ms were performed. For the statistical analysis, the distribution of the pulse flow is selected. The response was calculated according to the mathematical model under the conditions of a change in the speed of sound, which simulates a change in the sample inhomogeneity under load. The calculation showed a qualitative similarity with changes in responses in a real experiment. According to the obtained results, it was concluded that it is possible to use the deterministic and pseudo-random components of the responses in the reverberation condition to control the change in defectiveness and the degree of heterogeneity under the action of the mechanical load on the sample.


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