scholarly journals Span operational aspects under offsetting the axis of the track panel

2020 ◽  
Vol 164 ◽  
pp. 03037
Author(s):  
Alexey Loktev ◽  
Vadim Korolev ◽  
Irina Shishkina ◽  
Olga Lokteva ◽  
Ekaterina Gridasova
Keyword(s):  
Analytical Calculation ◽  
Solution Procedure ◽  
Free Vibrations ◽  
Railway Track ◽  
The Finite Element Method ◽  
Principal Stresses ◽  
Beam Design ◽  
Internal Forces ◽  
Vertical Vibrations ◽  
Angular Displacements

The stress-strain state of a small railway bridge with a beam design is considered in the article for the case of offsetting the track panel axis relative to the bridge axis by the value exceeding the limit determined by regulatory documents. The differential equation is considered in the analytical calculation of the behavior parameters and the state of the span under the action of the load. This equation describes the vertical vibrations of the beam and allows considering them as a combination of forced and free vibrations. In numerical modeling, the finite element method is used as the solution procedure. Determining equations of the method contain linear and angular displacements of nodes in the model as unknowns. As a result of the calculations, graphical dependences for normal and horizontal displacements, internal forces, principal and equivalent stresses at various points of the span are obtained. Values are presented that show an increase in bending and torsional forces, as well as in principal stresses when the axis of the railway track is displaced relative to the bridge axis.

scholarly journals Features of the bridge span performance when shifting the axis of the rail-sleeper grid

2020 ◽  
Vol 79 (3) ◽  
pp. 127-138
Author(s):  
V. V. Korolev ◽  
A. A. Loktev ◽  
I. V. Shishkina ◽  
E. A. Gridasova
Keyword(s):  
Concrete Strength ◽  
Analytical Calculation ◽  
Free Vibrations ◽  
Railway Track ◽  
Normal Operation ◽  
Cement Stone ◽  
Joint Work ◽  
Principal Stresses ◽  
Engineering Structures ◽  
Beam Design

Engineering structures form an integral part of the railways, both already operated and yet designed. The joint work of the upper structure of the railway track and the supporting structures of the bridge crossing is an important condition for the normal operation of the railway section without various restrictions and additional work on the current maintenance and diagnostics of structural elements. Presented study is devoted to the investigation of the stress-strain state of a small railway bridge with a beam design, when the axis of the rail-sleeper grid relative to the axis of the bridge is shifted by an amount exceeding the limit value determined by regulatory documents. In the analytical calculation of the behavior parameters and the state of the span under the action of the load, a differential equation is used that describes the vertical vibrations of the beam and allows considering them as a combination of forced and free vibrations. In numerical modeling, the finite element method is used as the solution method, the deter mining equations of which contain linear and angular displacements of nodes of the calculation scheme as unknowns. As a result of the calculations, graphical dependences for normal and horizontal displacements, internal forces, principal and equivalent stresses at various points of the span are obtained. Presented values show an increase in bending and torsional forces, as well as principal stresses when the axis of the railway track is displaced relative to the axis of the bridge. It is noted that although the increase in stresses (by about 6 %) can generally be considered insignificant, the presence of defects in the span beams (concrete chips, cracks in the stretched zone, exposure and corrosion of working reinforcement, decrease in the calculated cross section, leaching of cement stone from concrete, decrease in concrete strength over time) can make it a significant enough factor limiting the operational capabilities of bridge crossings.

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress

2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Medullary Bone ◽  
Principal Stresses ◽  
Bone Stress ◽  
Bone Damage ◽  
Rehabilitation System ◽  
Minimum Requirements

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

scholarly journals Numerical investigation of the effects of unsupported railway sleepers on train-induced environmental vibrations

2017 ◽  
Vol 36 (2) ◽  
pp. 160-176 ◽  
Author(s):  
Seyed-Ali Mosayebi ◽  
Morteza Esmaeili ◽  
Jabbar-Ali Zakeri
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Two Dimensions ◽  
Railway Track ◽  
Sensitivity Analyses ◽  
Regression Equations ◽  
The Finite Element Method ◽  
Technical Literature ◽  
Support Force ◽  
Comparison Of The Results

Review of technical literature regarding to train-induced vibrations shows that the effects of unsupported railway sleepers on this issue have been less investigated. So, the present study was devoted to numerical investigations of the mentioned issue. In this regard, first the problem of longitudinal train–track dynamic interaction was simulated in two dimensions by using the finite element method and the developed model was validated through comparison of the results with those obtained by previous researchers. In the next stage, a series of sensitivity analyses were accomplished to account for the effects of value of gap beneath the unsupported sleeper(s) and the track support stiffness on increasing the sleeper displacement and track support force. Moreover, the raised sleeper support force was introduced as applied load to a two-dimensional plane strain finite element model of track in lateral section and consequently the train-induced vibrations were assessed. As a result, a series of regression equations were established between the peak particle velocity in the surrounding environment of railway track and the sleeper support stiffness for tracks without unsupported sleepers and with one and two unsupported sleepers.

Researches on the Shear Deformation of Joints Domain of Beam-to-Column Connection of Light Steel Structure

2012 ◽  
Vol 256-259 ◽  
pp. 1004-1007
Author(s):  
Xi Bing Hu ◽  
Jian Hua Lu
Keyword(s):  
Finite Element Method ◽  
Shear Deformation ◽  
Design Method ◽  
Steel Structure ◽  
Structure Calculation ◽  
The Finite Element Method ◽  
Mechanics Performance ◽  
Current Design ◽  
Internal Forces ◽  
Complex Parts

The joint domain of beam-to-column connection is very complex parts under loading, which plays an important role in transferring internal forces in light steel structure, such as moment, shear, axial force and so on. Considering the influence of its shear deformation in the structure calculation can help us to reflect the actual mechanics performance and evaluate precisely practical bearing capacity of the structure. According to the actual characteristics of beam-to-column connection, the author established some models of its joint domain, and used the finite element method to analyze and calculate shear deformation of these models. Meanwhile, the author researched the influence of the changes of various parameters to its shear deformation, and provided beneficial suggestions for revising the current design method of light steel structure finally.

scholarly journals Modelling Plates and Shells by Means of the Rigid Finite Element Method

2015 ◽  
Vol 62 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Iwona Adamiec-Wójcik ◽  
Andrzej Nowak ◽  
Stanisław Wojciech
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibrations ◽  
The Finite Element Method ◽  
Hybrid Finite Element Method ◽  
Hybrid Finite Element ◽  
Rigid Finite Element Method ◽  
Plates And Shells ◽  
Single Set ◽  
Element Method

Abstract The rigid finite element method (RFEM) has been used mainly for modelling systems with beam-like links. This paper deals with modelling of a single set of electrodes consisting of an upper beam with electrodes, which are shells with complicated shapes, and an anvil beam. Discretisation of the whole system, both the beams and the electrodes, is carried out by means of the rigid finite element method. The results of calculations concerned with free vibrations of the plates are compared with those obtained from a commercial package of the finite element method (FEM), while forced vibrations of the set of electrodes are compared with those obtained by means of the hybrid finite element method (HFEM) and experimental measurements obtained on a special test stand.

scholarly journals Calculation of the goffered multilayered composite cylindrical shells by using the finite element method

1999 ◽  
Vol 21 (2) ◽  
pp. 116-128
Author(s):  
Pham Thi Toan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Cylindrical Shells ◽  
The Finite Element Method ◽  
Multilayered Composite ◽  
Internal Forces ◽  
External Loads ◽  
Element Method ◽  
Composite Cylindrical Shells

In the present paper, the goffered multilayered composite cylindrical shells is directly calculated by finite element method. Numerical results on displacements, internal forces and moments are obtained for various kinds of external loads and different boundary conditions.

The Research on Seismic Performance of Tower under Icing Condition

2014 ◽  
Vol 986-987 ◽  
pp. 677-680
Author(s):  
Yu Chen Tian ◽  
Wei Jian Xue ◽  
Ying Zhou ◽  
Lan Jiang
Keyword(s):  
Transmission Lines ◽  
Southwest China ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Seismic Action ◽  
The Finite Element Method ◽  
Three Dimensional Model ◽  
Deformation Law ◽  
Prone Area ◽  
Internal Forces

Southwest area of china is the zone of the transmission lines which often happens icing disaster. It is also an earthquake-prone area, also influenced by the interaction between ice and earthquake. This article uses the finite element method (fem), establishing three-dimensional model for steel towers in southwest china, to analyze the dynamic performance of the ice condition and the analysis of seismic action. The aim is to get internal forces for steel towers under the action of earthquake and deformation law along with the change of ice thickness.

Analysis by the mixed method of statically indeterminate frames with elements of increased rigidity and numerical verification of the calculation results using the finite element method

2021 ◽  
Vol 14 (2) ◽  
pp. 54-66
Author(s):  
Svetlana Sazonova ◽  
Viktor Asminin ◽  
Alla Zvyaginceva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Initial Data ◽  
Mixed Method ◽  
Numerical Verification ◽  
Bending Moments ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Internal Forces ◽  
Element Method

The sequence of application of the mixed method for calculating internal forces in statically indeterminate frames with elements of increased rigidity is given. The main system is chosen for the frame with one kinematic and one force unknown. The canonical equations of the mixed method are written, taking into account their meaning. Completed the construction of the final diagram of the bending moments and all the necessary calculations and checks. When calculating integrals, Vereshchagin's rule is applied. The solution of the problem is checked by performing the calculation using the computer program STAB12.EXE; the results of the calculations are numerically verified using the finite element method. An example of the formation of the initial data for the STAB12.EXE program and the subsequent processing of the calculation results, the rules for comparing the numerical results and the results obtained in the calculation of the frame by the mixed method are given.

Reliability Comparison of Trusses Made of Thin-Walled Steel Sections

2018 ◽  
Vol 931 ◽  
pp. 280-287
Author(s):  
Sergey V. Skachkov ◽  
Ekaterina Y. Golotaystrova
Keyword(s):  
Load Capacity ◽  
Reliability Function ◽  
System Failure ◽  
Entire System ◽  
The Finite Element Method ◽  
Probabilistic Technique ◽  
Steel Sections ◽  
Internal Forces ◽  
Thin Walled ◽  
Rod Structures

The authors suggest a new truss with nodal conjugations without misalignment in the nodes. They have a greater load capacity and reliability. The results have been confirmed by the calculation of the above-mentioned trusses by the finite element method. The reliability function of trusses made of thin-walled steel sections can be determined taking into account the rods destruction probability in the system. We consider a design with the most unfavorable design model in which the destruction of any rod leads to the entire system failure. For the truss refusal it is assumed that the yield point of the material is reached at least in one of its cores. A probabilistic technique for estimating the reliability of rod structures made of thin-walled steel sections has been proposed. Other parameters being equal, including the geometric dimensions of the truss, loads, the nature of their application one can determine the most rational scheme of the truss in terms of its reliability. Differences in nodes design and internal forces direction will lead to a change in their values in trusses elements. Thus, the trusses reliability will depend on the mathematical expectation of internal efforts, camber and flexibility.

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