scholarly journals Numerical Analysis on Mutual Influences in Urban Subway Double-Hole Parallel Tunneling

2014 ◽  
Vol 8 (1) ◽  
pp. 455-462
Author(s):  
Youzhi Shi ◽  
Xiufang Li

mutual influence of the double-hole tunnel evacuation of urban subways is one of key issues involving the subway construction safety. The asynchronous one-direction evacuation, synchronous one-direction evacuation and opposite evacuation methods are frequently used in double-hole tunnel evacuation. This paper establishes three-dimensional numerical model by using the finite element analysis software MIDAS/GTS v2.01 and mainly studies the mutual influences of tunnels in the asynchronous one-direction evacuation and synchronous one-direction evacuation. The following conclusions are concluded based on computing. The preliminary conclusion is that the influential distance between the evacuation section of two tunnels is 3D (D is the tunnel diameter) in the parallel tunnel asynchronous evacuation, namely when the lagging distance is more than 3D, the lagging evacuation tunnel will not affect the advance evacuation tunnel section. The asynchronous evacuation of the vertical distribution tunnel is divided into the up tunnel first evacuation and down tunnel first evacuation. For up tunnel first evacuation, the influence range of the lagging distance is 5D. For down tunnel first evacuation, the influence range of the lagging distance is 1D. For up tunnel first evacuation on the slope, the influence range of the lagging distance is 5D. On the whole, the influence of two tunnels in up tunnel first evacuation is bigger than it in down tunnel first evacuation. The numerical analysis results will have important theoretical meaning and application value for building technology of the parallel double-hole tunnel.

2015 ◽  
Vol 9 (1) ◽  
pp. 44-52
Author(s):  
Youzhi Shi ◽  
Xiufang Li

construction of near double-hole parallel tunnels frequently occurs in city subway evacuation. Studying the dynamical behaviors of the parallel tunnel construction, performing systematic numerical analysis and grasping mutual influences of different factors on the tunnel evacuation and different effects of surface sedimentation has important theoretical meaning and application value for the building technology of the parallel double-hole tunnel. This paper establishes a three-dimensional numeral model, analyzes influences of three main influence factors (tunnel distribution form, tunnel burying depth and tunnel gap) on the surrounding soil and surface sedimentation in double-hole tunnel synchronous evacuation. The conclusions indicate that the vertical distribution has the biggest influences on tunneling in horizontal distribution, vertical distribution and tilted distribution of two tunnels, followed by tilted distribution. The horizontal distribution has the minimal influence. With growth of the tunnel gap, the mutual influence between two tunnels will become smaller. With growth of the tunnel burying depth, the influences on tunneling will become bigger.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

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.


2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.


2020 ◽  
Vol 27 (1) ◽  
pp. 1-5
Author(s):  
Hanadi Naji ◽  
Nibras Khalid ◽  
Mutaz Medhlom

This paper aims at presenting and discussing the numerical studies performed to estimate the mechanical and thermal behavior of RC flat slabs at elevated temperature and fire. The numerical analysis is carried out using finite element programs by developing models to simulate the performance of the buildings subjected to fire. The mechanical and thermal properties of the materials obtained from the experimental work are involved in the modeling that the outcomes will be more realistic. Many parameters related to fire resistance of the flat slabs have been studied and the finite element analysis results reveal that the width and thickness of the slab, the temperature gradient, the fire direction, the exposure duration and the thermal restraint are important factors that influence the vertical deflection, bending moment and force membrane of the flat slabs exposed to fire. However, the validation of the models is verified by comparing their results to the available experimental date. The finite element modeling contributes in saving cost and time consumed by experiments.


2017 ◽  
Vol 7 ◽  
pp. 219-223
Author(s):  
Beril Demir Karamanli ◽  
Hülya Kılıçoğlu ◽  
Armagan Fatih Karamanli

Aims The aim of this study is to evaluate the effects of the chincup appliance used in the treatment of Class III malocclusions, not only on the mandible or temporomandibular joint (TMJ) but also on all the craniofacial structures. Materials and Methods Chincup simulation was performed on a three-dimensional finite element (FE) model. 1000 g (500 g per side) force was applied in the direction of chin-condyle head. Nonlinear FE analysis was used as the numerical analysis method. Results By the application of chincup, stresses were distributed not only on TMJ or mandible but also on the circummaxillary sutures and other craniofacial structures. Conclusions Clinical changes obtained by chincup treatment in Class III malocclusions are not limited by only mandible. It was seen that also further structures were affected.


2014 ◽  
Vol 644-650 ◽  
pp. 137-141
Author(s):  
Guo Sheng Zhang ◽  
Wei Zhou ◽  
Ye Chen ◽  
Jian Qiang Gong

According to the super large or heavy vehicle accidents existing wrecker cannot complete the wrecker rescue mission independent problems, puts forward the design of a practical game type crane wrecker. The hoisting mechanism as the research object, the traditional mechanical method is designed and calculated, then the three-dimensional entity model using 3D mechanical design software Solidworks, and imported into the finite element analysis software ANSYS to analyze the static mechanics characteristics of the structure, to improve the local strength of short position. On this basis, a lifting test vehicle prototype, rated load operation and overload operation condition test, and measure its subsidence. With the analysis of the experiment results, show that the design truck lifting organ can meet the demand of the technology.


2018 ◽  
Vol 195 ◽  
pp. 02008
Author(s):  
Yanuar Setiawan ◽  
Ay Lie Han ◽  
Buntara Sthenly Gan ◽  
Junaedi Utomo

The use of castellated beams has become more popular in the last two decades. The main idea for the use of these types of steel beams is to reduce their self-weight by providing openings in the web of wide flange (WF) or I sections. Numerous research on castellated beams has been conducted, the majority of the studies aimed to optimize the opening size and the shape configuration of the openings. A numerical analysis of castellated beams with oval openings was performed in this study. The sections under investigation had variations in the height-to-length ratios of the beam. The Do to D and b to Do ratios were kept at a constant. The D value was defined as the height of the beam, while Do is the height of the opening, and b is the width of the opening. The numerical analysis was performed by the finite element analysis using the STRAND7 software. The numerical model was further validated to the experimental data. The results showed that the developed finite element model resulted in a very good representation to the actual behavior of the sections.


2012 ◽  
Vol 562-564 ◽  
pp. 1943-1946
Author(s):  
Yong Hu ◽  
Jin Gan Song ◽  
Qing Zou ◽  
Ke Zhu ◽  
Xiao Long Wang

Because both of the volume and the weight of the photoelectric platform are small, the structure of two frames and two axes is used in the photoelectric platform. As the key component of the photoelectric platform, the main frame should have sufficient strength and rigidity. In order to achieve this object, three-dimensional entity model of the main frame is established using CATIA software. Then the finite-element analysis of the model is finished with ANSYS Workbench. Based on the analysis results, the weak links of the main frame is found. Then these links are improved and the main frame is analyzed again. After improving the structure, the results of the finite-element analysis show that the main frame meets the requirements of design and has perfect overall performance.


2014 ◽  
Vol 926-930 ◽  
pp. 52-55
Author(s):  
Lian Feng Lai ◽  
Cheng Hui Gao ◽  
Jian Meng Huang

A three-dimensional W-M fractal sliding model of double rough surfaces was established, and the factors of interface shear strength influenced the whole sliding process was considered. The velocity in Z direction of sliding processes was analyzed using the finite element analysis and taking into account of adhesion factors in the process of contact. The numerical results showed that the velocity in Z direction's fluctuation is larger, and the higher-frequency component is more with the decrease of the interface shear strength. Compared with experimental results and related documents, it is concluded the rationality of the results. The contact model between two rough solids will lay a foundation to further research on the substance of the process of friction and wear.


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