scholarly journals Numerical Analysis of a Train-Bridge System Subjected to Earthquake and Running Safety Evaluation of Moving Train

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Xun Yang ◽  
Huanhuan Wang ◽  
Xianlong Jin
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Element Model ◽  
Earthquake Intensity ◽  
Running Safety ◽  
Simulation Problem ◽  
Moving Train ◽  
Bridge System

This paper investigates the dynamic response of a train-bridge system subjected to earthquakes, and the running safety indices of the train on the bridge under earthquake are studied. Taking a long span cable-stayed bridge across the Huangpu River as an example, a full three-dimensional finite element model of the train-bridge system was established, in which the soil-bridge and rail-train interactions were considered. Parallel computing based on contact balance was utilized to deal with this large-scale numerical simulation problem. The dynamic nonlinear analysis was performed on a Hummingbird supercomputer using the finite element code LS-DYNA 971. The results show that the acceleration responses of the train subjected to an earthquake are much greater than the ones without earthquake input, and the running safety of a moving train is affected by both the earthquake intensity and the running speed of the train. The running safety of the moving train can be evaluated by the threshold curve between earthquake intensity and train speed. The proposed modeling strategies and the simulated results can give a reference prediction of the dynamic behaviour of the train-bridge subjected to an earthquake.

Three-Dimensional Seismic Analysis on Reactor Structure

2010 ◽  
Author(s):  
Naibin Jiang ◽  
Feng-gang Zang ◽  
Li-min Zhang ◽  
Chuan-yong Zhang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Earthquake Excitation ◽  
Finite Element Software ◽  
Reactor Structure ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The seismic analysis on reactor structure was performed with a new generation of finite element software. The amount of freedom degree of the model was more than twenty millions. The typical responses to operational basis earthquake excitation were given. They are larger than those with two-dimensional simplified finite element method, and the reasons of this phenomenon were analyzed. The feasibility of seismic analysis on large-scale three-dimensional finite element model under existing hardware condition was demonstrated, so some technological reserves for dynamic analysis on complicated equipments or systems in nuclear engineering are provided.

scholarly journals Three-Dimensional Response of the Supported-Deep Excavation System: Case Study of a Large Scale Underground Metro Station

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 76
Author(s):  
Ashraf Hefny ◽  
Mohamed Ezzat Al-Atroush ◽  
Mai Abualkhair ◽  
Mariam Juma Alnuaimi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Deep Excavation ◽  
Metro Station ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The complexities and the economic computational infeasibility associated in some cases, with three-dimensional finite element models, has imposed a motive for many investigators to accept numerical modeling simplification solutions such as assuming two-dimensional (2D) plane strain conditions in simulation of several supported-deep excavation problems, especially for cases with a relatively high aspect ratio in plan dimensions. In this research, a two-dimensional finite element model was established to simulate the behavior of the supporting system of a large-scale deep excavation utilized in the construction of an underground metro station Rod El Farrag project (Egypt). The essential geotechnical engineering properties of soil layers were calculated using results of in-situ and laboratory tests and empirical correlations with SPT-N values. On the other hand, a three-dimensional finite element model was established with the same parameters adopted in the two-dimensional model. Sufficient sensitivity numerical analyses were performed to make the three-dimensional finite element model economically feasible. Results of the two-dimensional model were compared with those obtained from the field measurements and the three-dimensional numerical model. The comparison results showed that 3D high stiffening at the primary walls’ corners and also at the locations of cross walls has a significant effect on both the lateral wall deformations and the neighboring soil vertical settlement.

Investigation on Slider Structure Deformation and Crowning System of Large-Scale Press Brake

2011 ◽  
Vol 201-203 ◽  
pp. 1500-1503
Author(s):  
Heng Li ◽  
Quan Kun Liu ◽  
Ling Yun Qian ◽  
Yu Han
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Small Deformation ◽  
Element Model ◽  
Numerical Control ◽  
Large Size ◽  
The Press ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Improving the straightness accuracy of bending workpieces becomes an urgent problem for the development of bending equipment with large size and high precision. In order to obtain the characteristics of slider deformation, a three-dimensional finite element model was developed according to the mechanic characteristics of large-scale press brake and obtained the small deformation using FEM (finite element method). The numerical results are in good agreement with the experimentation. Then based on the simulation results we design a large-scale mechanical crowning system through which the press brake could be automatically compensated in the bend direction by means of a CNC (Computer Numerical Control)-powered motor and could also be compensated for local parts by adjusting the side screw nuts manually. The system has been successfully applied in production and its accuracy was increased 33% compared with the traditional ones. It is proved that the present investigation can provide a technical support and reliable system for the improvement of accuracy of the press brakes.

Study on Seismic Safety Evaluation of RCC Gravity Dam Based on Strength

2014 ◽  
Vol 501-504 ◽  
pp. 1493-1497
Author(s):  
Shu He Wang ◽  
Ji Yuan ◽  
Rui Guo Ma ◽  
Ju Bing Zhang
Keyword(s):  
Finite Element ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Time History ◽  
Element Model ◽  
Gravity Dam ◽  
Seismic Safety ◽  
Finite Element Software ◽  
Three Dimensional Finite Element

According to No.3 dam section of Dahuaqiao gravity dam, a three-dimensional finite element model is built by finite element software ANSYS. Mechanics of materials method, response spectrum method and time history analysis method are employed to analyze the strength of the dam section. Results show that the stress of dam toe, dam heel and downstream fold slope are relatively high and stress concentration emerges in those positions. The phenomenon indicates that these areas are vulnerable under the earthquake and precautions must be taken. But under the designed earthquake, the maximum stress of the dam section is below the allowable stress, representing the dam is in a safe state and the strength requirement is satisfied.

The Research on the Influence of the Forms of Foundation on the Behavior of Adjacent Excavation Based on Building Materials

2013 ◽  
Vol 788 ◽  
pp. 606-610
Author(s):  
Qing Xiang Ji ◽  
Xin Sheng Ge
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Building Materials ◽  
Three Dimensional ◽  
Element Model ◽  
Deep Excavation ◽  
Foundation Pit ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Foundation pit excavation could be affected to some extent by surrounding different kinds of building materials, building structure, foundation form and load distribution, especially in intensive buildings. In this paper, based on the large-scale finite element software ANSYS, a three-dimensional finite element model is established to analyze the consequences of these complex and uncertain factors faced with by deep excavation projects and the conclusions of the excavation affected by different foundations form of adjacent buildings are arrived at.

Consideration of Geometric Imperfections in Three-Dimensional Finite Element Model Analysis of Stiffened Steel Liners Subjected to External Pressure

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
J. L. G. Valdeolivas ◽  
J. C. Mosquera
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Element Model ◽  
External Pressure ◽  
Hydropower Plant ◽  
Geometric Imperfections ◽  
Modeling And Analysis ◽  
Steel Liner ◽  
Three Dimensional Finite Element

The availability of tools for safety evaluation of a pressure liner is a relevant issue in both structural and hydraulic engineering. A suitable design of a steel liner may involve a significant reduction in the investment cost of a hydropower plant and may also ensure its future integrity, avoiding prolonged stoppages in the operation stage. First, a review of the design methods for steel pressure liners is outlined and certain key aspects for the critical buckling load assessment are pointed out. Second, a numerical modeling and analysis procedure of a steel pressure liner is presented. The methodology is based on 3D nonlinear finite element modeling procedures, involving both liner constraining and the effect of stiffeners. In addition, both large displacements and a surrounding elastic medium are assumed in the model. Besides, some types of geometric imperfections such as weld-induced ones, initial gap, ovality, and wall-thickness loss due to corrosion are taken into account in this work. Finally, some conclusions are drawn regarding the role of imperfections in the calculated critical pressure of a steel liner.

Composite steel-free deck bridges: Numerical modelling and pilot parametric study

2002 ◽  
Vol 29 (5) ◽  
pp. 662-678 ◽  
Author(s):  
Adel H Salem ◽  
Mohamed A El-Aghoury ◽  
Ezzeldin Y Sayed-Ahmed ◽  
Tarek S Moustafa
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Parametric Study ◽  
New Technology ◽  
Three Dimensional ◽  
Element Model ◽  
Steel Girders ◽  
Concrete Deck ◽  
Bridge System ◽  
Composite Steel

During the past decade, composite steel-free deck bridges came to reality in Canada through the construction of five bridges. The new structural system enables the construction of a concrete deck that is totally devoid of all internal steel reinforcement. Traditionally, reinforced concrete bridge decks are designed to sustain loads in flexure. The steel-free deck bridge system develops internal compressive forces "internal arching," which leads to failure by punching shear at substantially higher loads than the flexural design load. The fibre-reinforced concrete deck is usually attached to the steel girders through flexible shear connectors. These steel girders are transversely tied together by steel straps and cross frames. In this paper, the concept of the new bridge system is briefly discussed. The generations of the deck slabs are introduced. Brief outlines of the bridges built to date with this new technology are presented. A three-dimensional finite element model is then proposed to study the behaviour of the main structural component of the new system. The model is verified against previous experimental results and is used to perform a parametric study on some aspects which are thought to significantly affect the behaviour of the new steel-free deck bridge system.Key words: bridges, composite girders, finite element method, steel-free deck, steel straps.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

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