scholarly journals Experimental-Numerical Study of Indexation of Scenic Road Vertical Alignment in China

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ronghua Wang ◽  
Xingliang Liu ◽  
Zhe Yuan
Keyword(s):  
Field Experiments ◽  
Numerical Study ◽  
Design Method ◽  
Maximum Velocity ◽  
Vertical Alignment ◽  
Slope Length ◽  
Rapid Variation ◽  
Forest Park ◽  
Longitudinal Slope ◽  
Relative Errors

The vertical alignment design method of road in scenic spots does not evolve enough along the vehicle’s rapid variation. Values of the maximum longitudinal slope (MLS) and longest slope length (LSL) applicable to scenic roads used by the environmental-friendly vehicle (EFV) are not provided. To compensate for this shortage, a multibody vehicle dynamic model in uphill traving is built, providing the static equilibrium state and dynamic balancing process of a typical vehicle. MLS and LSL values in scenic roads are obtained based on this model through numerical simulation, considering typical EFV, maximum velocity loss (MVL), and ideal velocity loss (IVL). Field experiments for verifying the results are also carried out in Huashan Mountain, Cuihua Mountain National Park, and Taiping Forest Park, using two EFV types. MLS and LSL values in scenic roads applicable to EFV obtained in this research vary from 7.8% to 10.2% and 200 to 955 m, respectively, and both are larger than the corresponding values in current criteria. According to verification results, relative errors of climbing velocity vary from 0.0104 to 0.0205, showing the dynamic model’s accuracy and further proving the practicality of MLS and LSL values obtained. The results obtained in this research lay a foundation for establishing the scenic-road vertical alignment design method.

Test and Numerical Study on the Seismic Performance of A Cable Restrainer for Girder Bridges

2019 ◽  
Author(s):  
Yitong Gu ◽  
Wancheng Yuan ◽  
Xinzhi Dang
Keyword(s):  
Seismic Performance ◽  
Numerical Study ◽  
Design Method ◽  
Lateral Displacement ◽  
Static Test ◽  
Girder Bridges ◽  
Continuous Girder Bridge ◽  
Service Conditions ◽  
Girder Bridge ◽  
Parametric Analyses

<p>In China, most of the support systems applied by short/medium span bridges are elastomeric pad bearings (EPBs). This type of support system has no reliable connections between bearings and girders as well as bearings and piers, which will cause structural damages due to large lateral displacement of bearings under earthquakes. The restrainers used currently could restrict the deformation of bridges under normal service conditions and could only restrict unidirectional displacement. Considering the disadvantages of these restrainers, a new restrainer called Connected Cable Restrainer (CCR), which can be used in short/medium span bridges supported by EPBs, is developed in this paper. The design principle, basic configuration, isolation mechanism and the design method of CCR are introduced. A pseudo static test to study the seismic performance of CCR is conducted. Seismic responses of a 3-span continuous girder bridge with CCR are simulated using OpenSees platform and parametric analyses of the two main parameters, lateral restraining displacement and restraining stiffness, are also carried out. Results show that the deformation of bridges under normal service conditions would not be restrained using CCR and the displacement responses can be mitigated effectively by using CCR through parameter optimization.</p>

scholarly journals An Optimization Design Method of Combination of Steep Slope and Sharp Curve Sections for Mountain Highways

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Lei Yue ◽  
Hui Wang
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Steep Slope ◽  
Lateral Acceleration ◽  
Driving Safety ◽  
Estimation Model ◽  
Lateral Instability ◽  
Slope Length ◽  
Maximum Slope ◽  
Regular Design

As it was found steep slope and sharp curve sections account for 14% of the accident-prone sections according to the accidents data in Chongqing. Regular design indices with certain thresholds are found not enough for this kind of mountain highways. The goal of this paper is to find an optimization design method for combination of steep slope and sharp curve sections based on the analysis of vehicle driving stability. The overall safety model of steep slope and sharp curve combined section is established, and the relevant coordination relationship between design indices of the front and rear alignment unit is established by using the operating speed estimation model. Taking the maximum slope length corresponding to the specified design speed as the design condition of the front segment, the threshold values and variation rules of the design indices of the rear segment under different design speeds are calculated ensuring driving safety. The safety model is simulated by CarSim software, the trajectory offset and lateral acceleration are used to indirectly reflect the degree of lateral instability, and the results are compared to verify the effectiveness of the simplified safety model established in this paper.

scholarly journals Failure Characteristics of Joint Bolts in Shield Tunnels Subjected to Impact Loads from a Derailed Train

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Qixiang Yan ◽  
Zhixin Deng ◽  
Yanyang Zhang ◽  
Wenbo Yang
Keyword(s):  
Impact Load ◽  
Numerical Study ◽  
Design Method ◽  
Shield Tunnel ◽  
Failure Behavior ◽  
Impact Loads ◽  
Fe Model ◽  
Fe Modelling ◽  
Bolt Failure ◽  
The Impact

Impact loads generated by derailed trains can be extremely high, especially in the case of heavy trains running at high speeds, which usually cause significant safety issues to the rail infrastructures. In shield tunnels, such impact loads may not only cause the damage and deformation of concrete segments, but also lead to the failure of segmental joint bolts. This paper presents a numerical study on the failure behavior of segmental joint bolts in the shield tunnel under impact loading resulting from train derailments. A three-dimensional (3D) numerical model of a shield tunnel based on the finite element (FE) modelling strategy was established, in which the structural behavior of the segmental joint surfaces and the mechanical behavior of the segmental joint bolts were determined. The numerical results show that the occurrence of bolt failure starts at the joints near the impacted segment and develops along the travel direction of train. An extensive parametric study was subsequently performed and the influences of the bolt failure on the dynamic response of the segment were investigated. In particular, the proposed FE model and the analytical results will be used for optimizing the design method of the shield tunnel in preventing the failure of the joint bolts due to the impact load from a derailed HST.

Derivative Design of Axial Fan Range: From Academia to Industry

2016 ◽  
Author(s):  
Tommaso Bonanni ◽  
Lucio Cardillo ◽  
Alessandro Corsini ◽  
Giovanni Delibra ◽  
Anthony G. Sheard ◽  
...  
Keyword(s):  
Performance Prediction ◽  
Good Accuracy ◽  
Design Method ◽  
Three Dimensional ◽  
Correct Prediction ◽  
Preliminary Design ◽  
Axial Fan ◽  
Data Set ◽  
Axial Fans ◽  
Relative Errors

The work presented in this paper concerns a useful method for axial fans preliminary design based on the “Derivative Design” concept. The emphasis is, on one side, on education and, on the other, on the practical help that such method can provide in the early preliminary design process. A complete data set of an axial fan measured with ISO 5801 standards is the start point for the investigation and the prediction of the multiple possible performance that different fan configurations can provide, in terms of dimensionless duty coefficients. In particular, configurations with different number of blades, and hence of solidity, are studied. The typical options of derivative design are explored and relations for performance prediction are presented. A detailed description of the derivative design methodology is followed by tests and validation. The tools employed are a fully three dimensional code, the Advanceded Actuator Disk Mode (AADM), and two other in-house codes, the Meanline Axisymmetric Calculation (MAC) and Axisymmetric Laboratory (AXLAB). Results of the derivative design method are reported, showing a good accuracy against the AADM data. The MAC and AXLAB ensure still acceptable results when increasing the solidity of the machine. On the contrary, a decrease of solidity leads to higher relative errors in the prediction of the load coefficient. In conclusion, an exploration of the possible fields of operation of a blade profile can be carried out by a correct prediction of the stage diffusion factor.

Numerical study of the elasto-plastic buckling in perforated thin steel plates using the constructal design method

2018 ◽  
Author(s):  
Daniel Helbig ◽  
◽  
Marcelo Langhinrichs Cunha ◽  
Caio Cesar Cardoso da Silva ◽  
Elizaldo Domingues dos Santos ◽  
...  
Keyword(s):  
Numerical Study ◽  
Design Method ◽  
Steel Plates ◽  
Plastic Buckling ◽  
Constructal Design ◽  
Thin Steel

Design Method and Performance Effects of Curvature-Smooth Centrifugal Compressor Blades

2015 ◽  
Author(s):  
Qingzhen Bi ◽  
Hua Chen ◽  
Ding Tong ◽  
Yaoan Lu ◽  
Xueqi Zou
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Design Method ◽  
Blade Surface ◽  
Compressor Blades ◽  
Transonic Centrifugal Compressor ◽  
Performance Effects ◽  
Section Curve ◽  
And Performance ◽  
Fifth Order

Blade curvature has an important effect on the pressure distribution over the blade surface as well as the quality of airfoil machining, but curvature smoothing method in design environments is little studied. A new geometry generator is developed for the design of curvature-smooth airfoils. The sections of an airfoil can be initially designed by a conventional method, and each of the sections is then regenerated by fitting a fifth order B-spline curve. The first order differential of the curvature with respect to arc length of the blade surface is used as a curvature smoothness measure. The distance between discrete points and the curve, and the integral of the square of the first derivative along the streamwise section curve are simultaneously minimized in the fitting process. The design of a transonic centrifugal compressor for turbocharger application is presented to study the effects of the curvature-smooth blade on centrifugal compressor performance. A numerical study was carried out and the results are discussed.

Research on the Design of Linear Drive Motor of New Pumping Unit

2012 ◽  
Vol 433-440 ◽  
pp. 5025-5031 ◽  
Author(s):  
Wen Zhong Ma ◽  
Hong Mei Zhang ◽  
Jin Yan Sun ◽  
De Bao Tian ◽  
Hong Fei Pang
Keyword(s):  
Field Experiments ◽  
Design Method ◽  
Linear Motor ◽  
Structure Design ◽  
Operating Efficiency ◽  
Electromagnetic Design ◽  
Linear Induction Motor ◽  
New Energy ◽  
Design Requirements ◽  
Pumping Unit

The new energy saving pumping unit driven by linear induction motor (LIM) not only can overcome many disadvantages of traditional beam-pumping unit, but also has a lot of advantages, such as reliability, high operating efficiency, etc. So it arouses the universal concern of the oil industry. This paper focuses on the study of linear motor. Firstly, it analyzes the advantages of the pumping unit driven by LIM relative to beam-pumping unit, then in accordance with the system design requirements and based on the electromagnetic design method of linear motor, makes the theoretical calculation and the structure design of the motor, determines specific parameters of LIM, produces LIM applicable to the practical application to drive pumping unit. Lastly, makes field experiments, and experiments results show that LIM has reached the design requirements, also verify the correctness and feasibility of the design method.

scholarly journals Studi Numerik Steady RANS Aliran Fluida di Dalam Asymmetric Diffuser

2017 ◽  
Vol 4 (1) ◽  
pp. 20 ◽  
Author(s):  
Yiyin Klistafani
Keyword(s):  
Fluid Flow ◽  
Pressure Gradient ◽  
Numerical Study ◽  
Maximum Velocity ◽  
Turbulence Models ◽  
Adverse Pressure Gradient ◽  
Positive Pressure ◽  
Front Wall ◽  
Human Beings ◽  
Vertical Side

Research on fluid flow becomes a necessity to develop technology and for the welfare of human beings on earth. One of them is study of fluid flow in the diffuser. The example of diffuser application is used as a flue gas duct in the car or motorcycle. In addition, diffuser is also applied in air conditioning systems. Diffuser is a construction that able to control the behavior of the fluid. The increasing of cross section area in the diffuser will generate a positive pressure gradient or also called adverse pressure gradient (APG). The greater APG that happens, the greater energy required by the fluid to fight it, because APG will lead to separation. This study aimed to evaluate the numerical fluid flow in the asymmetric diffuser with divergence angle (θ) = 10 ° (upper wall) and widening one vertical side (α) of 20 ° (front wall). The Reynolds number is 8.7 x 104 by high inlet diffuser and the maximum velocity at the inlet diffuser. Turbulence models used are standard k-ɛ, realizable k-ε, and shear stress transport (SST) k-ω. Numerical study of steady RANS used Fluent 6.3.26 software. Results of numerical visualizations show that huge vortex established in diffuser, that’s why performance of diffuser is not optimal. In addition the location of separation point shown by SST k-ω is earlier than other turbulence models (standard k-ε and realizable k-ε).

scholarly journals Hydrodynamic Performance and Cavitation Analysis in Bottom Outlets of Dam Using CFD Modelling

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Omid Aminoroayaie Yamini ◽  
S. Hooman Mousavi ◽  
M. R. Kavianpour ◽  
Ramin Safari Ghaleh
Keyword(s):  
Flow Pattern ◽  
Flow Rate ◽  
Numerical Study ◽  
Maximum Velocity ◽  
Hydrodynamic Performance ◽  
Earth Dam ◽  
Cfd Modelling ◽  
Cavitation Phenomenon ◽  
Bottom Outlets ◽  
Bottom Outlet

Bottom outlets are significant structures of dams, which are responsible for controlling the flow rate, operation, or removal of reservoir sedimentation. The service gate controls the outlet flow rate, and whenever this gate is out of order, the emergency gate which is located at upstream is utilized. The cavitation phenomenon is one of the common bottom outlets’ problems due to the rapid flow transfer. The present research is a numerical study of the flow pattern in a dam’s bottom outlet for different gate openings by the use of Flow-3D software and RNG k-ε turbulence model. The investigation is carried out on the Sardab Dam, an earth dam in Isfahan (Iran). The maximum velocity for 100% opening of the gate and Howell Bunger valve is about 18 m/s in the section below the gate, and the maximum velocity for 40% opening of the gate is equal to 23.1 m/s. For 50% opening of the service and emergency gate in the valve’s upstream areas, the desired pressure values are reduced. Moreover, in the areas between the two emergency and service gates, the pressure values are reduced. The possibility of cavitation in this area can be reduced by installing aerators. The flow pattern in Sardab Dam’s bottom outlet has relatively stable and proper conditions, and there are no troublesome hydraulic phenomena such as local vortices, undesirable variations in pressure, and velocity in the tunnel, and there is no flow separation in the critical area of flow entering into the branch.

scholarly journals EFFECT OF DITCHING'S PARAMETERS ON OPERATION QUALITY OF ORCHARD DITCHING-FERTILIZER MACHINE

2021 ◽  
pp. 477-487
Author(s):  
ChunBao Xu ◽  
HongJian Zhang ◽  
ShuangXi Liu ◽  
Chengfu Zhang ◽  
Junlin Mu ◽  
...  
Keyword(s):  
Deflection Angle ◽  
Rotation Speed ◽  
Design Method ◽  
Coverage Rate ◽  
Forward Speed ◽  
Stability Coefficient ◽  
Machine Performance ◽  
The Deflection Angle ◽  
Relative Errors ◽  
The Stability

This study aims to evaluate the effects of different parameter settings on the ditching performance using a ditching-fertilizer. We aimed to improve the performance of ditching-fertilizer machine performance in sustainable agriculture. With Box-Behnken experimental design method, taking forward speed, the rotation speed of the ditching cutter, and the deflection angle of ditching cutter as experimental factors, taking ditching depth stability and soil coverage rate as test indexes, the operation parameters of orchard ditching-fertilizer machine are studied. The regression model between test indexes and experimental factors is established, and the influence of each factor on the experimental indexes is analyzed. The test factors are comprehensively optimized. The results show that when the forward speed is 0.8km/h, the rotation speed of the ditching cutter is 348r/min, and the deflection angle of the ditching cutter is 32°, the ditching effect is the best. At this time, the stability coefficient of the ditching depth is 98.33%, and the soil coverage rate is 81.53%. As for the field test, which measured the stability coefficient of ditching depth, and the average soil cover rate is 96.24%, and 79.14%, respectively, and the relative errors from the optimized value are 2.17%, and 3.02%, respectively.

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