Method of combining theoretical calculation with numerical simulation for analyzing effects of parameters on the maglev vehicle-bridge system

Author(s):  
Wentao Xia ◽  
Jiewei Zeng ◽  
Fengshan Dou ◽  
Zhiqiang Long
2012 ◽  
Vol 151 ◽  
pp. 291-294
Author(s):  
Jian Hua Cui ◽  
Ping Liu

Based on the construction of the transfer floor of Yunding project in Chengdu, to solve the issues from the integral stability and safety of the transfer beam high-formwork supporting system, the method of the theoretical calculation, the method of the numerical simulation and real-time monitoring were applied in order to make some conclusions. The conclusions will be significance to apply in the future similar projects for reference and guidance.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Wei Liu ◽  
Wenhua Guo

This paper presents a framework for the linear random vibration analysis of the coupled three-dimensional (3D) maglev vehicle-bridge system. Except for assembling the equation of motion of vehicle only via the principle of virtual work, the fully computerized approach is further expanded to assemble the governing equation of fluctuating current via the equilibrium relation. A state-space equation couples the equation of motion of the vehicle and the governing equation of fluctuating current. The equation of motion of a real three-span space continuous girder bridge is established by using finite element methods. A separated iteration method based on the precise integration method and the Newmark method is introduced to solve the state-space equation for the maglev vehicle and the equation of motion for the bridge. Moreover, a new scheme to application of the pseudoexcitation method (PEM) in random vibration analysis is proposed to maximize the computational efficiency of the random vibration analysis of the maglev vehicle-bridge system. Finally, the numerical simulation demonstrates that the proposed framework can efficiently obtain the mean value, root mean square (RMS), standard deviation (SD), and power spectral density (PSD) of dynamic response for the coupled 3D maglev vehicle-bridge system.


ICRT 2017 ◽  
2018 ◽  
Author(s):  
Simin Zou ◽  
Xuhui He ◽  
Teng Wu ◽  
Yunfeng Zou ◽  
Haiquan Jing

Author(s):  
XingYing Ji ◽  
Lai Xu ◽  
Xiao Liu

Put forward a method of calculating the axial thrust of Francis turbine. To use numerical simulation computing the axial thrust on hub, shroud and blade of inner runner, combine theoretical methods calculating the pressure on hub and shroud of outer runner, finally the axial thrust of Francis turbine is obtained. The results of calculation agree with the results of model test. It is an effective way of gathering the theoretical calculation and numerical simulation to calculate the axial thrust of Francis turbine. In addition the static suction of turbine has great effect on calculation results of the axial thrust. The static suction of turbine plays a significant role on the lifting of turbine.


2021 ◽  
Author(s):  
Haoshuai Wu ◽  
Yanlong Chen ◽  
Haoyan Lv ◽  
Qihang Xie ◽  
Yuanguang Chen ◽  
...  

Abstract The highwall miner can be used to mine the retained coal in the end slope of an open-pit mine. However, the instability mechanism of the reserved rib pillar under dynamic and static loads is not clear, which restricts the safe and efficient application of the highwall mining system. In this study, the load-bearing model of the rib pillar in highwall mining was established, the cusp catastrophe theory and the safety coefficient of the rib pillar were considered, and the criterion equations of the rib pillar stability were proposed. Based on the limit equilibrium theory, the limit stress of the rib pillar was analyzed, and the calculation equations of plastic zone width of the rib pillar in highwall mining were obtained. Based on the Winkler foundation beam theory, the elastic foundation beam model composed of the rib pillar and roof under the highwall mining was established, and the calculation equations for the compression of the rib pillar under dynamic and static loads were developed. The results show that with the increase of the rib pillar width, the total compression of the rib pillar under dynamic and static loads approximately decreases in an inverse function, and the compression of the rib pillar caused by static loads of the overlying strata and trucks has a decisive role. Numerical simulation and theoretical calculation were performed in this study. In the Numerical simulation, the coal seam with a buried depth of 122 m and a thickness of 3 m was mined by the highwall miner. According to the established rib pillar instability model of the highwall mining system, it is found that when the mining tunnel width is 3 m, the reasonable width of the rib pillar is at least 1.3 m, and the safety factor of the rib pillar is 1.3. The numerical simulation results are in good agreement with the results of theoretical calculation, which verifies the feasibility of the theoretical analysis of the rib pillar stability. The research results can provide an important reference for the stability analysis of rib pillars under highwall mining.


Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4513 ◽  
Author(s):  
Feng Cui ◽  
Tinghui Zhang ◽  
Xingping Lai ◽  
Jiantao Cao ◽  
Pengfei Shan

Aiming at the serious problems caused by coal mine mining activities causing the rock burst accidents, this paper is based on rock mechanics and material mechanics to establish the key layer breaking by the double-key layer beam breaking structural mechanics model of a single working face and double working face under repeated mining. The theoretical calculation formula of the angle was used as the theoretical basis for the elevation angle of the pre-reloading hole of the hard roof. The rationality and reliability of the formula were verified by the physical similarity simulation experiment and the 3 Dimension Distinct Element Code numerical simulation experiment, revealing the rock formation under the influence of repeated mining. The results show that the derived key layer breaking angle formula is suitable for the theoretical calculation of the breaking angle of the key layer of a single coal seam when the repeated disturbance coefficient is λ = 1; when it is λ = 2, it is suitable for the repeated mining of the short-distance double-coal mining. The rationality and reliability of the theoretical formula of the breaking angle of the double key layer of single coal seam and double coal seam were verified by the physical similarity simulation experiment. Through the 3DEC numerical simulation results and theoretical calculation results, the W1123 working face hard top pre-cracking pressure relief drilling elevation angle was 78°. The drilling peeping method was used to verify the results. The results show that the theoretical formula of the critical layer breaking angle is well applied in engineering practice.


2013 ◽  
Vol 415 ◽  
pp. 498-501 ◽  
Author(s):  
Shu Xun Li ◽  
Lian Cui Li ◽  
Ying Zhe Hou

Aiming at the leakage problem on the top of gate valve, the finite element method is used to analyze the gate valves seal face and body, as well as the distributing laws of the stress, deformation and seal pressure are obtained. The shutter is simplified as the circular plate simply supported on the whole circle, and the gate valve is optimized according to the relevant formula to meet sealing requirement. The results show that: the combination of the numerical simulation and theoretical calculation, not only the more accurate theoretical basis for the optimization of the large diameter gate valve can be provided, but also the time of the development and design can be shorten greatly.


2018 ◽  
Vol 10 (8) ◽  
pp. 168781401878925 ◽  
Author(s):  
Bin Xia ◽  
Fanyu Kong ◽  
Hui Zhang ◽  
Lei Yang ◽  
Wanghuan Qian

In this article, three types of high-speed mine submersible pumps were designed and experimented. During the reliability performance test, the axial thrust balancing device of GFQ150-700 was overloaded and damaged due to an unsuitable designed value of axial thrust. The designed hydraulic axial thrust with the actual value is compared in this article, and the reason for axial thrust deviation is discussed. Results show that axial thrust of the theoretical calculation is close to the numerical simulation value at a certain extent. GFQ100-1000 obtains the maximum theoretical axial thrust, while the maximum simulated value is produced in GFQ150-700, and that is corroborated by experiments. The axial blade force is related to the pump stage and area differences between the blade suction and pressure surface. Due to the increasing stage in GFQ100-1000, the axial blade force increases to a remarkable value in an opposite direction with respect to GFQ150-700. The opposite blade force offsetting other hydraulic forces in GFQ100-1000 is responsible for the maximum hydraulic axial thrust emerges in GFQ150-700 instead of GFQ100-1000.


2010 ◽  
Vol 154-155 ◽  
pp. 68-73
Author(s):  
Bin Gao ◽  
Bai Zhong Wu

Products made from double-layered hollow vacuum forming are widely used for their various advantages. The hollow vacuum forming process has been studied in this paper. Numerical simulation method for the hollow vacuum forming process of double-layered plastic sheets has been introduced by the simulation software Polyflow, which is suitable for viscoelasticity fluid bodies. This method can vividly and intuitively estimate the thickness, temperature variation and distribution in the double-layered vacuum forming processes. Based on this method, reliably theoretical calculation data can be provided to design the reasonable vacuum forming process for double-layered vacuum forming of new materials or new products. The proposed method has been verified to be applicable and effective by prototype fabrications.


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