scholarly journals Calculation of Reasonable Tension Value for Longitudinal Connecting Reinforcement of CRTSII Slab Ballastless Track

2018 ◽  
Vol 8 (11) ◽  
pp. 2139 ◽  
Author(s):  
Long Chen ◽  
Jinjie Chen ◽  
Jianxi Wang
Keyword(s):  
Prestressed Concrete ◽  
Crack Width ◽  
Mechanical Characteristics ◽  
Tensile Force ◽  
Three Dimensional ◽  
Element Model ◽  
Railway Track ◽  
Tension Force ◽  
Original Design ◽  
Ballastless Track

There is confusion in the original design concept for the tensioning of longitudinally connected reinforcement of the CRTSII (China Railway Track System) slab ballastless track. In order to clarify the effect of tension value of longitudinal reinforcement on the mechanical characteristics of the ballastless track, a three-dimensional finite element model, considering the nonlinear interaction between the track slab and cement-emulsified asphalt (CA) mortar of the CRTSII slab ballastless track, was established. The mechanical characteristics of the track structure under longitudinal tension load and temperature gradient load of the longitudinal joint were calculated. A method of applying prestress to post-pouring concrete was proposed according to the concept of prestress loss of pretensioning prestressed concrete, a reasonable tensile force value was proposed after the crack width, and the reinforcement stress of the ballastless track in the operation stage was checked and calculated according to the concrete design principle. When the tension force is greater than 300 kN, it is harmful to the bonding between the slab and mortar layer, which is prone to interlayer damage. In order to add prestress to concrete with wide joints to ensure the longitudinal stability of the ballastless track, and that the reinforcement stress and crack width meet design requirements, it is suggested that the tension force value should be 230 kN. Further, the temperature difference between reinforcement and concrete should be 30 °C before the initial curdle of wide joint concrete.

scholarly journals Calculation of Reasonable Tension Value for Longitudinal Connecting Reinforcement of CRTSII Slab Ballastless Track

2018 ◽  
Author(s):  
Long Chen ◽  
Jin-jie Chen ◽  
Jian-xi Wang
Keyword(s):  
Crack Width ◽  
Mechanical Characteristics ◽  
Tensile Force ◽  
Three Dimensional ◽  
Element Model ◽  
Tension Force ◽  
Original Design ◽  
Ballastless Track ◽  
Longitudinal Joint ◽  
Three Dimensional Finite Element

There is a confusion in the original design concept for the tensioning of longitudinally connected reinforcement of CRTSII slab ballastless track. In order to clarify the effect of tension value of longitudinal reinforcement on mechanical characteristics of ballastless track, a three dimensional finite element model considering the nonlinear interaction between the track slab and CA mortar of CRTSII slab ballastless track was established. The mechanical characteristics of the track structure under longitudinal tension load and temperature gradient load of the longitudinal joint were calculated. A method of applying pre-stress to post-pouring concrete was proposed according to the concept of pre-stress loss of pretensioning pre-stressed concrete, reasonable tensile force value was proposed after the crack width and the reinforcement stress of the ballastless track in the operation stage were checked and calculated according to the concrete design principle. When the tension force is greater than 300 kN, it’s harmful to the bonding between the slab and mortar layer, which is prone to interlayer damage. In order to adding pre-stress to concrete of wide joints to ensure the longitudinal stability of ballastless track and the reinforcement stress and crack width to meet the design requirements. It is suggested that the tension force value should be 230 kN, and the temperature difference between reinforcement and concrete should be 30 °C before the initial curdle of wide joint concrete.

scholarly journals Fatigue Behavior of Prestressed Concrete Beam for Straddle-Type Monorail Tracks

2018 ◽  
Vol 8 (7) ◽  
pp. 1136 ◽  
Author(s):  
Qianhui Pu ◽  
Hanyu Wang ◽  
Hongye Gou ◽  
Yi Bao ◽  
Meng Yan
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Element Model ◽  
Transportation Systems ◽  
Traffic Load ◽  
Prestressed Concrete Beam ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Monorail transportation systems are widely built in medium and small cities, as well as hilly cities, because of their excellent performance. A prestressed concrete track beam is a key load-carrying structural component and guideway subjected to repeated traffic load. The fatigue behavior of the prestressed concrete beam is critical for the safety of the transportation system. This paper presents the results of an experimental study on the fatigue behavior of a prestressed concrete beam in terms of stiffness degradation and strain change. The displacement and rotation of the beam of concrete and reinforcement were examined, respectively. A three-dimensional finite element model was established to help understand the development of the mechanical behavior. No crack was observed throughout the test. Both concrete and bars behaved in their linear-elastic stage throughout the test, and the bond between them performed well.

Finite Element Analysis of a Fishplate Rail Joint in Extreme Environment Condition

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Sunil Kumar Sharma ◽  
Jaesun Lee
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Extreme Environment ◽  
High Rate ◽  
Railway Track ◽  
Element Analysis ◽  
Track System ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Railways are very efficient mode of transportation. Speed limits of the railways and loads they carry are increasing rapidly. Due to some advantages, the insulated rail joints are still the part of a rail-track system. However, a high rate of failure of joints puts the railway track at risk. Therefore, a detailed study of these joints is required. In this paper, a three-dimensional finite element model of rail-fishplate joint is created using Abaqus - a finite element method-based software. Stresses in fishplate and bolts due to wheel impact are analysed by coupling implicit and explicit methods. It is found that bolts are a critical part of a joint due to stresses and vibrations to which they are subjected. The large number of stresses and vibration can result into loosening of bolts.

The Characteristic of Prestressed Concrete Pier Seismic Crack

2014 ◽  
Vol 501-504 ◽  
pp. 1628-1632
Author(s):  
Hui Li Wang ◽  
Hong Wang ◽  
Si Feng Qin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Element Model ◽  
Dimensional Finite Element ◽  
Tensile Zone ◽  
Three Dimensional Finite Element ◽  
Prestressed Reinforcement

Through three dimensional finite element analyzes, overall cast-in-place prestressed concrete pier seismic crack characteristic is researched. The separation formula finite element model is established by means of bilinear reinforce model and Kent-R.Park concretes model, without considering slip between concretes and. reinforce. It compares and analyzes the seismic crack characteristic between prestressed concrete pier and reinforcement concretes pier. The results show that the prestressed reinforcement can reduce the tensile zone of concrete, put off the appearance of cracks, improved the stiffness of pier, and reduced the top displacement.

Evaluation and Analysis of the Onlay Patellar Component in Total Knee Arthroplasty

2010 ◽  
Vol 97-101 ◽  
pp. 3773-3776 ◽  
Author(s):  
Chien Wei Liu ◽  
Chia Chi Lo ◽  
Ching Sung Wang ◽  
Chen Tung Yu
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Three Dimensional ◽  
Element Model ◽  
Clinical Results ◽  
Original Design ◽  
Design Modification ◽  
Patellar Component ◽  
Significant Difference ◽  
Total Knee

Complications in total knee arthroplasty (TKA), which may include the inaccuracy of the implantation and the poor component design, can cause major failures in the TKA. Therefore, the present investigation studies the onlay knee implants commonly used clinically to find the major causes of the damage to artificial patella by the computer aided analysis of the three-dimensional finite element model of the artificial patello-femoral joint built through reverse engineering. Results showed that although a significant difference is found in the condition and the state of the stress distribution generated as the patello-femoral joint changes with the flexion of the knees, this variation is still within the tolerable range; but the patellar lateral tilt is something that caught our attention. Furthermore, through the comparison between the study and the clinical results, this investigation concludes that the bone cement on the implant interface is the major cause for the breaking of the pegs, and is not related to the original design of the patella. This study also discovers that slight design modification on the parts of commonly used artificial joints may effectively reduce surgical failure rate; therefore, a more robust design configuration for patellar pegs is proposed.

scholarly journals Study of the railway embankment operation that crossing faults upland movements at different angles

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Semyon Isaev
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Railway Track ◽  
Tectonic Activity ◽  
Engineering Structures ◽  
Main Site ◽  
Fault Block ◽  
Longitudinal Slope ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The article discusses the issues of the railway embankment operation crossing faults with upland movements at different angles. Examples of the engineering structures operation are given in this article: tunnels, bridges, roadbed, pipelines in conditions of tectonic activity. Existing regulatory documents recommend choosing a route with a bypass of the places where tectonic faults reach the ground’s surface. However, taking into account the existing fault-block structure of the ground’s crust, it is practically impossible to bypass the tectonic fault zones. The existing network of railways for the most part was laid without taking into account modern requirements norms. Therefore, it seems relevant to study the operation of both the operated and the projected railway track in the tectonic disturbances zones with upland movements. In this article, using the software and computing complex Midas GTS, designed for geotechnical calculations, a study of the railway embankment operation crossing at different angles in the horizontal plane faults with conditional upland movements of the fault block has been carried out. For this, a three-dimensional finite element model was created. The calculations used the Coulomb-Mohr elastoplastic soil work model. As a result, the deformations of the embankment’s main area were analyzed. The deformations components and their contribution to the overall value are considered in detail. Conclusions are made about the change in the longitudinal slope of the axis and the skew of the transverse profile of the main site. For the most deformed sections, normal and tangential stresses diagrams. The research results analysis made it possible to establish a number of characteristic regularities in the change in the embankment’s stress-strain state, depending on the angle between the track and the fault axes. The article is part of the author’s dissertation research

Structural Optimization of Reinforced Concrete Aqueduct with Multi-Longitudinal Beams Part I: Method

2011 ◽  
Vol 243-249 ◽  
pp. 335-338
Author(s):  
Jun Feng Guan ◽  
Xiao Ke Li ◽  
Shun Bo Zhao
Keyword(s):  
Reinforced Concrete ◽  
Tensile Stress ◽  
Crack Width ◽  
Mechanical Characteristics ◽  
Shell Element ◽  
Element Model ◽  
Optimization Method ◽  
Internal Force ◽  
Structural Deformation ◽  
Maximum Crack

Former approaches fordesigning reinforced concrete aqueduct with multi-longitudinal beams were mostly based on experience. In this study, an optimization method is proposed instead. According to the mechanical characteristics of aqueduct, optimization principlesfor structural deformation coordination and sectional crack-resisting are developed. Furthermore, in optimization of large and complex reinforced concrete aqueduct, this method employs nominal tensile stress to control the maximum crack width. In addition, a 3D beam-shell element model is suggested for calculating internal force of aqueduct.

Three Dimensional Finite Element Analysis of Composite Laminates with Non-Penetrating Damage Repaired by Scarf Bonding Method

2010 ◽  
Vol 26-28 ◽  
pp. 370-375
Author(s):  
Feng Liu ◽  
Wen Feng Qin ◽  
Guo Chun Liu
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Principal Direction ◽  
Tensile Force ◽  
Three Dimensional ◽  
Element Model ◽  
Damage Mode ◽  
Bismaleimide Resin ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the stress state of the composite laminates under unidirectional tensile force is analyzed. The strength criterion and damage mode are given based on the stresses of material principal direction. The three dimensional finite element model of the same laminates with non-penetrating damage repaired by scarf bonding method is built, and the stress state is also analyzed. The strength criterion and the damage mode of the scarf bonding composite laminates are also given. The strength and the damage mode of original laminates are compared with that of the laminates with non-penetrating damage. The influence of the interlaminar stress is considered in these analysis models. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the original composite laminates made of carbon fiber reinforced bismaleimide resin and the repaired one both damage first in the laminar whose second material principal direction coincides with the axial tensile force. And the damage mode is resin crack under tensile stress. The strength of the bonding patches is higher than the laminates repaired by scarf bonding. After scarf bonding repair, the strength of the damaged laminates can recover up to about eighty-four percent.

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