Requirements for static and fatigue strength of beams front axle of a truck

2021 ◽  
pp. 3-9
Author(s):  
Кh.A. Faskhiev

Based on the results of road tests of the stress-strain state of the beam of the controlled bridge of a dump truck, recommendations for its design were developed. The most loaded zones of the beam under operating conditions have been identified. The safety margins of the bridge beam in bending and torsion, the ratio of the moments of resistance to bending in the vertical and horizontal planes have been determined. The test mode and the standard of the bench fatigue life of the bridge beam have been established. Keywords: bridge beam, truck, strength, bending, twisting, load, dynamic factor, safety margin, operational requirements

Author(s):  
V.V. LEONTYEV ◽  
E.V. KONDRATOVA ◽  
V.P. KOLOMIYCHENKO

Traditional methods for calculating welded joints are based on approximate methods for determining the forces that occur in the joint. This leads to inaccuracies in the definition of stress. In addition, this approach does not allow obtaining a complete picture of the stress-strain state of the joint. All this leads to the need to increase the coefficient of safety margin and, as a result, to increase the cost of construction. The proposed method of calculating the connection using the finite element method allows us to determine the stresses in all the elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the connection. As a result, it is possible to reduce the complexity of creating a compound and its mass. The finite element method should be used for calculating critical connections with complex operating conditions. An example of calculating such a connection is considered. A comparative analysis of the results of calculating the t-joint using the arm Joint module Of the WinMachine arm system and the Abaqus finite element package is performed.


2018 ◽  
Vol 22 (4) ◽  
pp. 66-74 ◽  
Author(s):  
A. A. Vasilkin

In steel tanks made by the method of rolling, defects of a geometric shape often occur in the area of the welded welded joint of the wall. Subsequently, in these areas, as a result of low cycle fatigue, an unacceptable defect appears in the form of a crack, which makes it necessary to remove the reservoir from operation and carry out a set of measures for its repair. To determine the terms of safe operation of vertical steel tanks with geometric defects, it is proposed to use the methodology control of the actions of structures of load-bearing structures, one of the directions of which is the regulation of the stress-strain state of steel structures. To implement the possibility of regulating construction, it is necessary to identify such parameters, the change of which will give the maximum effect in achieving the set goals. As the indicated parameters, the design characteristics (material properties, design scheme, geometric characteristics) and factors of external influences (load, operating conditions) can act. To regulate the stress-strain state design of vertical steel tanks, the following regulators are proposed: product loading height, wall deflection arrow and permissible number of tank loading cycles. By numerical calculation of the VAT of the vertical steel tank design with geometric defects, the necessary values and values of the stress state are determined. Further, using known analytical dependencies from the field of fracture mechanics, it is possible to determine the permissible number of loading cycles of the reservoir before the appearance of a crack-like defect. The application of the methodology control of the actions of structures load-bearing structures, by means of a certain change in the established control parameters, allows increasing the number of loading cycles of the reservoir, thereby increasing the period of safe operation of the defective reservoir and thereby increasing the economic efficiency of the tank farm.


2020 ◽  
Vol 25 (1) ◽  
pp. 236-242
Author(s):  
T.I. Zaitseva ◽  
I.V. Blinova ◽  
A.M. Uzdin

AbstractThe problem of gap estimation for a break of a continuous welded rail is studied. The track is represented as a semi-infinite rod on elastic-based damping. Static and dynamic solutions are obtained. It is shown that during the rail break, the dynamic factor does not exceed 1.5. We derive equations for thermal deformation of the welded rail of jointless track on an elastic foundation in the presence of the insert into the base with another characteristic stiffness. It is shown that the presence of the insertion of up to 20% of the length of the rail, with both large and small stiffness, has a little effect on the stress-strain state (SSS) of the track. The presence of a rigid insert may increase the clearance of an accidental break of the rail, which has a negative effect on traffic safety.


Author(s):  
V. F. Danenko ◽  
◽  
L. M. Volgograd State Technical University

A computer finite-element simulation of the stress-strain state of elements of a closed rope under conditions of joint tension and torsion has been carried out. The redistribution of axial forces and torques in the cross sections of layers during rotation of the rope under the influence of external torque was determined, which leads to a decrease in the safety margin of the rope, a violation of the compatibility of axial and radial movements in the layers and the structural integrity of the rope in the form of wire breakage of the outer layer.


2021 ◽  
Vol 22 (1) ◽  
pp. 36-42
Author(s):  
Andrey A. Chistyakov ◽  
Valery P. Timoshenko

In this work, the most rational schemes to designing the skin of a full-turning vertical empennage element (stabilator) have been studied. Skin designing schemes were chosen according to aero-spacecraft operating conditions in the re-entry trajectory. During designing process, the requirements for reusable structures of tourist-class aero-spacecrafts were taken into account, such as: maximum simplicity and endurance of the product. To determine the mechanical loads acting on the keel during its movement in the air, a numerical simulation of the aerodynamic flow-around the stabilator profile at 5 arbitrary points on the flight path was carried out. The parameters used for the analysis are: flight velocity, density and viscosity of the air. Of the 5 obtained fields of dynamic pressure acting on the stabilator, the field that creates the largest distributed load was used as the boundary condition for the analysis of the stress-strain state of the structure. The problem of mechanical loading of the stabilator was solved separately for each of the previously studied structural schemes of the skin. Based on the obtained calculation results the optimal skin structural scheme was chosen by comparing the displacements on the line connecting ribs.


2021 ◽  
Vol 266 ◽  
pp. 01022
Author(s):  
Z.A. Besheryan ◽  
I.F. Kantemirov

The development of Russian fuel and energy complex in the short term is connected with the development of new hydrocarbon field in the permafrost zone and the need to build Arctic pipelines north of the 60th parallel. The ground-based structural scheme of pipeline laying is the most optimal while constructing trunk pipelines in permafrost areas in the Arctic and subarctic latitudes. The actual operating conditions of these systems are insufficiently studied. The above-ground pipeline in permafrost is in an complex stress-strain state. This study presents the results of the assessment of the stress-strain state of linearly extended above-ground pipelines at different compensation sections (triangular compensator; trapezoidal compensator; U-shaped compensator) under actual operating conditions. Using the finite element method on mathematical models, the dependences of the transverse displacements of the pipeline on movable supports and stresses arising in dangerous sections of the typical pipeline section during self-compensation of deformations on the variable design parameters of the system for various load combinations were established (the simulation was carried out in the ANSYS software package).


Author(s):  
Leonid Dyachenko ◽  
Andrey Benyn ◽  
Vladimir Smyrnov

Objective: Improvement of dynamic analysis method of simple beam spans in the process of high-speed trains impact. Methods: Mathematical modeling with numerical and analytical methods of building mechanics was applied. Results: The parameters of high-speed trains influence on simple beam spans of bridges were analyzed. The method of dynamic factor to live load determination was introduced. The reliability of the method in question was corroborated by the results of numerical simulation of high-speed trains’ movement by beam spans with different speeds. The introduced algorithm of dynamic analysis was based on the connection between maximum acceleration of a beam span in resonance vibration mode and the basic factors of stress-strain state. The method in question makes it possible to determine both maximum and bottom values of main loading in a construction, which determines the possibility of endurance tests. It was noted that dynamic additions for the components of stress-strain state (bending moments, shear force, vertical deflections) were different. The fact in question determines the necessity of differential approach application to identify dynamic factors in the process of calculation testing on the first and the second groups of limit states. Practical importance: The method of dynamic factors’ determination presented in the study makes it possible to perform dynamic analysis and determine the main loading in simple beam spans without application of numerical modeling and direct analytical analysis, which considerably reduces labor costs on engineering.


2021 ◽  
Vol 263 ◽  
pp. 03009
Author(s):  
Ilya Ovchinnikov ◽  
Vladimir Avzovin

Quite a lot of works have been devoted to the problem of modeling the behavior of thin-walled structures exposed to an aggressive environment leading to corrosive wear of their surface. Researchers have proposed a fairly large set of models of corrosive wear, taking into account the influence of various factors on the kinetics of corrosion (time, material, temperature, the nature of the corrosive environment, the stress-strain state of the structure). Moreover, different authors often propose different models for the same conditions. In the article under consideration, a rather unique comparative study of three corrosion models proposed by different authors (Dolinsky V.M., Gutman E.M., Ovchinnikov I.G.) was carried out to simulate the behavior of the same circular plate subjected to the combined action of load and corrosion wear and tear. Moreover, the identification of the models, that is, the determination of the coefficients included in them, was carried out using the same experimental data. These models were then used to simulate the behavior of plates subject to corrosive wear under various loads. The results of numerical simulation were compared with experimental data obtained during testing of corrosive plates. Interestingly, in the models used, the effect of the stress state on the kinetics of corrosion was taken into account using different invariants of the stress state: the stress intensity in V.M. Dolinsky, medium voltage in the model of E.M. Gutman, and the specific energy in the model of I.G. Ovchinnikov. The analysis showed that the difference from the experiment when using the three models considered does not exceed 9.3%. The discrepancy between the results obtained using different models is also within the acceptable range, which suggests that all three models can be used to predict the behavior of plates under corrosive wear conditions. However, it is of interest to conduct research on the predictive capabilities of models on large forecast arms that go beyond the scope of experimental studies. At the same time, carrying out numerical experiments to simulate the behavior of complex structures in a stressed state and subject to corrosive wear, using several models that allow a good description of the experimental data and the most complete consideration of the operating conditions, makes it possible to obtain a more complete and versatile picture of what is happening in design processes, in comparison with the calculations performed according to one model, even if it describes the experimental data well.


Author(s):  
O. I. DUBINCHYK ◽  
L. O. NEDUZHA

Purpose. Bridge supports with a high pile caps require more attention when calculating their strength due to the difficult operating conditions of the piles. The purpose of the scientific article is to substantiate the stress-strain state of the pile foundation of the bridge structure using software computing systems SCAD and LIRA-CAD. Methodology. An analysis of software used to automate the design of foundations was conducted. The main parameters of SCAD and LIRA-CAD software packages are yielded. With their help, finite-element models of the pile foundation of the bridge support with a high pile cap were built. The developed models maximally reflect the properties of the soil base and foundation, its pile cap and piles, geometric characteristics and the influence of the finite elements meshing is considered. Calculations were performed in SCAD and LIRA-CAD software packages with monitoring of the calculation process. Findings. During the numerical analysis of the pile foundation of the bridge structure with a high pile cap, vertical displacements, force factors (normal forces and bending moments) in the piles and stresses in the body of the support and piles were determined. Based on these results, an analysis was performed, which is combined with a comparison of the obtained results. Implementation of SCAD and LIRA-CAD software allows to significantly reduce design time, to reduce project costs, to improve the quality and efficiency of investments. Originality. A comparison of the stress-strain state obtained during the numerical analysis of SCAD and LIRA-CAD software, which proved the difference in the approach to modeling in these complexes, was conducted. Practical value. The results of substantiation of the stress-strain state of the pile foundation with the use of software complexes made it possible to verify the design solution of all elements of the foundation of the bridge structure with a high pile cap.


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