scholarly journals The Effects of Load Location on Dropper Stress in a Catenary System for a High-Speed Railway

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Fan He ◽  
Dandan Guo
Keyword(s):  
Tensile Stress ◽  
High Speed ◽  
Computer Code ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Free Boundaries ◽  
Sinusoidal Vibration ◽  
Contact Wire ◽  
Stress Changes ◽  
Load Location

In this paper, the effects of load location on dropper stress are studied. We treat contact wire as a beam element and derive its response equation and then deduce the stress equation of dropper. A computer code based on MATLAB is written to calculate dropper stress using the finite difference method. The results show that there are three stages during the period of the stress changes of dropper, including instant rebound, damped sinusoidal vibration, and bending compression. The shorter the distance away from a load is, the larger the vertical displacement of the dropper is, which results in the corresponding increases of its stress amplitude and the maximum tensile stress. The load location has a significant impact on the stress changes of dropper. Compared to the condition of the load in the middle, the load acting on the edge of contact wire could induce the larger tensile stress when both ends of contact wire are considered as free boundaries. Therefore, it is necessary to add supports at both ends.

scholarly journals Numerical study of contact wire tension affecting dropper stress of a catenary system

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402199504
Author(s):  
Fan He ◽  
Dandan Guo ◽  
Liming Chen
Keyword(s):  
Tensile Stress ◽  
High Speed ◽  
Stress Amplitude ◽  
Numerical Study ◽  
Maximum Tensile Stress ◽  
Wire Tension ◽  
Contact Wire ◽  
Stress Changes ◽  
Response Equation ◽  
Catenary System

Dropper is the key component of in a catenary system and it is prone to fatigue fracture. Dropper stress directly affects the operation safety of high-speed railway. In this paper, a span of dropper in a catenary system is modeled to investigate the effects of contact wire tension on dropper stress. The response equation of contact wire and the theoretical equation of dropper stress are deduced. The initial and boundary conditions of each dropper are determined, and then the stress of each dropper is calculated by the finite difference method using a MATLAB program. The results show that the stress amplitude and the maximum tensile stress of the dropper decrease significantly with the increase of contact wire tension. When the tension is low, the stress changes of dropper near the load location experience three stages: instant rebound, attenuated vibration, and bending compression. However, the attenuation vibration stage disappears when the tension is increased to a certain extent. Therefore, the control of the vibration response of the contact wire can effectively reduce the stress amplitude and the maximum tensile stress of the dropper, so as to improve the working reliability of the dropper.

Mechanical Behavior of Segmented Lining Structure of Tunnel under Acting Ground Fractures in Xi’an Zone

2011 ◽  
Vol 261-263 ◽  
pp. 1778-1783
Author(s):  
Sheng Jun Shao ◽  
Fang Tao She ◽  
Juan Fang
Keyword(s):  
Tensile Stress ◽  
Mechanical Behavior ◽  
Compressive Stress ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Internal Force ◽  
Subway Tunnel ◽  
Lining Structure ◽  
Pass Through

Xi’an ground fracture, caused by the extraction of groundwater and the movement of fault under soil strata, is a geo-hazard. The movement of ground fracture originates the uneven settlement of upward block and downward block. In Xi’an ground fracture region, the segmented lining structure was adopted in subway tunnel to pass through the ground fracture, so as to adapt for the uneven settlement. Three-dimensional elastic-plastic finite difference method was applied to simulate the initial lining structure, second segmented lining structure, surrounding soils and ground fracture. The horizontal and vertical displacement of segmented lining structure, surrounding soils pressure and internal force of segmented lining structure in subway tunnel were analyzed by the calculation results. The knowledge on mechanical behavior of segmented lining structure passing through an active ground fracture and surrounding soils was shown as following. The relative vertical displacement between segmented lining structure sects beside the ground fracture increases remarkably with the movement of ground fracture, and the segmented lining structure located in upward displaceent block near ground fracture originates notable rotary. Tension or compression deformation occured in the deformation joint between adjacent segmented lining structures near the ground fracture.There was a significant change in the contact pressure of the first sect of lining structure in the upward displace block. Under the same uniform settlement at the bottom of upward diaplacement block, the relativly vertical displacemtn on the surfaceof ground fracture strata without tunnel equals 50cm, but the relativly vertical displacement between adjacent segmented lining structure at ground fracture is 18.2cm on the design level of arch top of lining strcutre. the maximum tensile stress of segmented lining structure is 2.02MPa, the maximum compressive stress of segmented lining is 3.49MPa. In conclusion, segmented lining structure can adapts to the uneven settlement caused by the movement of ground fracture. Though maximum tensile and compressive stress of sengmented lining structure passing through the active ground fracture is bigger than the general lining structure located in soils strata without the ground fracture, the segmented lining structure constructed by the steel fibre concrete can bear with the maximum tensile stress.

scholarly journals Analysis on accumulated deformation and stress of the steel roof of Beijing Opera House during construction

2021 ◽  
Vol 2045 (1) ◽  
pp. 012014
Author(s):  
L L Wu ◽  
G Gao ◽  
B R Ye ◽  
H D Zhang ◽  
Q Lu
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Design Model ◽  
Construction Process ◽  
Maximum Compressive Stress ◽  
Finite Element Software ◽  
Stress And Deformation ◽  
Steel Roof

Abstract This paper aims to study the stress and deformation of large steel structure buildings in the actual construction process. Midas Gen finite element software is used to simulate and analyze the whole construction process of the curved reticulated shell roof, the peripheral steel columns and the permanent support. The stress and deformation results of the structure in the final construction state are compared with those in the design state under one-time loading. The results show that, in the final construction state, the maximum tensile stress and the maximum compressive stress are 1.9 times and 2.0 times of that in the design state under one-time loading respectively, which is very significant. When the design model is loaded with weight at one time, the maximum tensile stress and the maximum compressive stress of the structure both appear near the opening of the steel roof, while in the final construction state, the maximum tensile stress of the structure appears near the boundary frame beam, and the maximum compressive stress appears on the main ridge beam. The maximum vertical displacement of the structure in the final construction state is 2.0 times of that when the design model is loaded at one time. The maximum vertical displacement of the design state appears near the opening of the steel roof, while the maximum vertical displacement of the structure in the final construction state appears on the main ridge beam. In view of the above, the effective guidance for the construction of steel roof structure is provided in this paper to ensure the safety of the structure.

UAV-LiDAR-Based Measuring Framework for Height and Stagger of High-Speed Railway Contact Wire

2021 ◽  
pp. 1-14
Author(s):  
Yixuan Geng ◽  
Fengjun Pan ◽  
Limin Jia ◽  
Zhipeng Wang ◽  
Yong Qin ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Contact Wire

scholarly journals Integration of an InSAR and ANN for Sinkhole Susceptibility Mapping: A Case Study from Kirikkale-Delice (Turkey)

2021 ◽  
Vol 10 (3) ◽  
pp. 119
Author(s):  
Hakan A. Nefeslioglu ◽  
Beste Tavus ◽  
Melahat Er ◽  
Gamze Ertugrul ◽  
Aybuke Ozdemir ◽  
...  
Keyword(s):  
High Speed ◽  
Fundamental Problem ◽  
Vertical Displacement ◽  
Deformation Monitoring ◽  
Susceptibility Mapping ◽  
Susceptibility Map ◽  
Engineering Structures ◽  
Conditioning Factors ◽  
High Deformation ◽  
Settlement Site

Suitable route determination for linear engineering structures is a fundamental problem in engineering geology. Rapid evaluation of alternative routes is essential, and novel approaches are indispensable. This study aims to integrate various InSAR (Interferometric Synthetic Aperture Radar) techniques for sinkhole susceptibility mapping in the Kirikkale-Delice Region of Turkey, in which sinkhole formations have been observed in evaporitic units and a high-speed train railway route has been planned. Nine months (2019–2020) of ground deformations were determined using data from the European Space Agency’s (ESA) Sentinel-1A/1B satellites. A sinkhole inventory was prepared manually using satellite optical imagery and employed in an ANN (Artificial Neural Network) model with topographic conditioning factors derived from InSAR digital elevation models (DEMs) and morphological lineaments. The results indicate that high deformation areas on the vertical displacement map and sinkhole-prone areas on the sinkhole susceptibility map (SSM) almost coincide. InSAR techniques are useful for long-term deformation monitoring and can be successfully associated in sinkhole susceptibility mapping using an ANN. Continuous monitoring is recommended for existing sinkholes and highly susceptible areas, and SSMs should be updated with new results. Up-to-date SSMs are crucial for the route selection, planning, and construction of important transportation elements, as well as settlement site selection, in such regions.

Technology of the Contact Wire Manufacture for High-Speed Railways

2021 ◽  
Vol 410 ◽  
pp. 173-178
Author(s):  
Andrey V. Sulitsin ◽  
Raisa K. Mysik ◽  
Vadim V. Morgunov
Keyword(s):  
High Speed ◽  
Profile Analysis ◽  
Cold Drawing ◽  
Casting Process ◽  
Sediment Layer ◽  
Contact Wire ◽  
X Ray ◽  
Inner Surface ◽  
Full Profile ◽  
Continuously Cast

The article presents an overview of possible technological schemes to produce an overhead contact wire for railways. Pilot experiments were carried out on the manufacture of a contact wire made of CuMg0.3, CuMg0.4 and CuMg0.5 alloys and having a nominal cross section of 100 mm2. The contact wire was obtained from a continuously cast rod with small section, which was subjected to plastic deformation using the Conform technology and cold drawing of the extruded rod. In the casting process, we encountered the formation of cracks on the cast rod surface and the rods breakage. The inner surface of the graphite bushings of the mold after casting the rod was studied and a thin gray layer was found on the inner surface of the graphite bushings. Areas of the graphite bushing with gray layer were studied by scanning electron microscopy and element-by-element mapping was performed with the selection of a spectrum in the sediment layer area. In order to determine the phase composition of the sediment layer it was analyzed by the method of full-profile analysis of the X-ray diffraction pattern according to Rietveld. X-ray phase analysis showed the CuMg2 and Cu2Mg phases presence. This allowed us to assume a possible mechanism for the formation of the sediment layer. Ultimate tensile strength, elongation and electrical resistivity was determined. Analysis showed that the overhead wires made of CuMg0.3, CuMg0.4, CuMg0.5 alloys meets the requirements of GOST R 55647-2018 for wires made of the second conditional group bronze.

Internal Stress Change of Phosphorus-Doped Amorphous Silicon Thin Films During Crystallization

1994 ◽  
Vol 343 ◽  
Author(s):  
Hideo Miura ◽  
Asao Nishimura
Keyword(s):  
Thin Films ◽  
Tensile Stress ◽  
Internal Stress ◽  
Crystallization Process ◽  
Chemical Vapor ◽  
Stress Change ◽  
Silicon Thin Films ◽  
Stress Changes ◽  
Phosphorus Doped ◽  
Deposited Films

ABSTRACTInternal stress change of phosphorus-doped silicon thin films during crystallization is measured by detecting substrate curvature change using a scanning laser microscope. The films are deposited in an amorphous phase by chemical vapor deposition using Si2H6 gas. The deposited films have compressive stress of about 200 MPa. The internal stress changes significantly to a tensile stress of about 800 MPa at about 600 °C due to shrinkage of the films during crystallization. The high tensile stress can be relaxed by annealing above 800 °C. The phosphorus doping changes the crystallization process of the films and their final residual stress.

Effect of Hydrogen on the Fracture Behavior of High-Strength Cr-Mo Steel

2006 ◽  
Vol 512 ◽  
pp. 55-60 ◽  
Author(s):  
Mao Qiu Wang ◽  
Eiji Akiyama ◽  
Kaneaki Tsuzaki
Keyword(s):  
Tensile Stress ◽  
Power Law ◽  
High Strength ◽  
Maximum Tensile Stress ◽  
Maximum Principal Stress ◽  
Slow Strain Rate Test ◽  
Diffusible Hydrogen ◽  
Thermal Desorption Spectrometry ◽  
Stress Concentration Factors ◽  
Peak Value

We examine the hydrogen embrittlement susceptibility of a high-strength AISI 4135 steel by means of a slow strain-rate test (SSRT) using notched round bar specimens. Hydrogen was introduced into the specimens by electrochemical charging and its content was measured by thermal desorption spectrometry (TDS). It was found that the maximum tensile stress decreased in a power law manner with increasing diffusible hydrogen content. Finite element method (FEM) calculations demonstrated that the peak value of the maximum principal stress and the peak value of the locally accumulated hydrogen concentration at the maximum tensile stress were in good agreement with one power law relationship for the specimens with different stress concentration factors.

Maximum Stress at Intersecting Bores of Pressurized Blocks

1994 ◽  
Author(s):  
Ajay Garg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Stress ◽  
Element Model ◽  
Maximum Tensile Stress ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Empirical Methods ◽  
Element Analysis ◽  
Matched Design

Abstract In high pressure applications, rectangular blocks of steel are used instead of cylinders as pressure vessels. Bores are drilled in these blocks for fluid flow. Intersecting bores with axes normal to each other and of almost equal diameters, produce stresses which can be many times higher than the internal pressure. Experimental results for the magnitude of maximum tensile stress along the intersection contour were available. A parametric finite element model simulated the experimental set up, followed by correlation between finite element analysis and experimental results. Finally, empirical methods are applied to generate models for the maximum tensile stress σ11 at cross bores of open and close ended blocks. Results from finite element analysis and empirical methods are further matched. Design optimization of cross bores is discussed.

scholarly journals Finite Element Simulation and Multi-Factor Stress Prediction Model for Cement Concrete Pavement Considering Void under Slab

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5294
Author(s):  
Bangyi Liu ◽  
Yang Zhou ◽  
Linhao Gu ◽  
Xiaoming Huang
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Mesh Size ◽  
Maximum Tensile Stress ◽  
Concrete Pavement ◽  
Slab Thickness ◽  
Void Size ◽  
Tensile Stresses

Uneven support as result of voids beneath concrete slabs can lead to high tensile stresses at the corner of the slab and eventually cause many forms of damage, such as cracking or faulting. Three-dimensional (3D) finite element models of the concrete pavement with void are presented. Mesh convergence analysis was used to determine the element type and mesh size in the model. The accuracy of the model is verified by comparing with the calculation results of the code design standards in China. The reliability of the model is verified by field measurement. The analysis shows that the stresses are more affected at the corner of the slab than at the edge. Impact of void size and void depth at the slab corner on the slab stress are similar, which result in the change of the position of the maximum tensile stress. The maximum tensile stresses do not increase with the increase in the void size for relatively small void size. The maximum tensile stress increases rapidly with the enlargement in the void size when the size is ≥0.4 m. The increments of maximum tensile stress can reach 183.7% when the void size is 1.0 m. The increase in slab thickness can effectively reduce maximum tensile stress. A function is established to calculate the maximum tensile stress of the concrete slab. The function takes into account the void size, the slab thickness and the vehicle load. The reliability of the function was verified by comparing the error between the calculated and simulated results.

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