Finite Element Analysis of the Surface Settlement Induced by the Shield Tunnel Construction

2014 ◽  
Vol 501-504 ◽  
pp. 111-114
Author(s):  
Ling Xia Gao ◽  
Xiang Jun Yang ◽  
Li Kun Qin

Three-dimensional non-linearity finite element model of shield tunnel was established on basis of the Z1 line of Tianjin subway. And then it was applied to simulate construction process of shield tunnel. Surface settlement of the tunnel during the construction was obtained. The settlement data of transverse and longitudinal direction from numerical simulation were fitted through a polynomial expression. Then a contrastive analysis of curves from numerical simulation and matching formulae were made. The result shows that it is feasible to utilize the empirical formulas like Pecks to predict surface settlement in Tianjin caused by shield construction.

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti

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.


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.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak

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.


2011 ◽  
Vol 27 (3) ◽  
pp. 309-320 ◽  
Author(s):  
C.-Y. Fan ◽  
C.-K. Chao ◽  
C.-C. Hsu ◽  
K.-H. Chao

ABSTRACTAnterior Lumbar Interbody Fusion (ALIF) has been widely used to treat internal disc degeneration. However, different cage positions and their orientations may affect the initial stability leading to different fusion results. The purpose of the present study is to investigate the optimum cage position and orientation for aiding an ALIF having a transfacet pedicle screw fixation (TFPS). A three-dimensional finite element model (ALIF with TFPS) has been developed to simulate the stability of the L4/L5 fusion segment under five different loading conditions. The Taguchi method was used to evaluate the optimized placement of the cages. Three control factors and two noise factors were included in the parameter design. The control factors included the anterior-posterior position, the medio-lateral position, and the convergent-divergent angle between the two cages. The compressive preload and the strengths of the cancellous bone were set as noise factors. From the results of the FEA and the Taguchi method, we suggest that the optimal cage positioning has a wide anterior placement, and a diverging angle between the two cages. The results show that the optimum cage position simultaneously contributes to a stronger support of the anterior column and lowers the risk of TFPS loosening.


2011 ◽  
Vol 291-294 ◽  
pp. 3282-3286 ◽  
Author(s):  
Jiang Wei Wu ◽  
Peng Wang

In port crane industry, the surface hardening technique is widely used in order to improve the strength of wheel. But the hardening depth is chosen only by according to the experience, and the effect of different hardened depths is not studied theoretically. In this paper, the contact stresses in wheel with different hardening depth have been analyzed by applying three-dimensional finite element model. Based on this model, the ANSYS10.0 finite element software is used. The elastic wheel is used to verify the numerical results with the Hertz’s theory. Three different hardening depths, namely 10mm, 25mm and whole hardened wheel, under three different vertical loads were applied. The effect of hardening depth of a surface hardened wheel is discussed by comparing the contact stresses and contact areas from the numerical results.


2011 ◽  
Vol 201-203 ◽  
pp. 1601-1605 ◽  
Author(s):  
Shang Ping Chen ◽  
Wen Juan Yao ◽  
Sheng Qing Zhu

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.


2007 ◽  
Vol 44 (01) ◽  
pp. 16-26
Author(s):  
Ömer Eksik ◽  
R. Ajit Shenoi ◽  
Stuart S. J. Moy ◽  
Han Koo Jeong

This paper describes the development of a finite element model in order to assess the static response of a top-hat-stiffened panel under uniform lateral pressure. Systematic calculations were performed for deflection, strain, and stress using the developed model based on the ANSYS three-dimensional solid element (SOLID45). The numerical modeling results were compared to the experimental findings for validation and to further understand an internal stress pattern within the different constituents of the panel for explaining the likely causes of the panel failure. Good correlation between experimental and numerical strains and displacements was achieved.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  

Abstract Background Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments. Methods A three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations. Results MOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments. Conclusion The three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.


2013 ◽  
Vol 442 ◽  
pp. 229-232 ◽  
Author(s):  
Li Mei Wu ◽  
Fei Yang

According to the cutting theory of involute tooth profile, established an exact three-dimensional parametric model by UG. Used ABAQUS to crate finite element model for gear meshing. After simulated the meshing process, discussed the periodicity of the tooth surface contact stress. Based on the result of finite element analysis, made a comparison of the maximum contact stress between finite element solution and Hertz theoretical solution, analyzed the contact stress distribution on tooth width, and researched the effect of friction factor on contact stress. All that provided some theoretical basis for gear contact strength design.


2013 ◽  
Vol 273 ◽  
pp. 588-592
Author(s):  
Zhi Yuan Yan ◽  
Dong Mei Wu ◽  
Li Tao Zhang ◽  
Jun Zhao

In order to obtain high-quality analytical results of the finite element model, it is essential to construct a three dimensional geometric model. The paper reconstructed an accurate three dimensional geometric model of cervical spine segments (C4-C7). The process of reconstruction included three-dimensional reconstruction, smooth processing, contour generation, grid generation and fitting surface. Moreover, the result of reconstruction was evaluated ultimately. The model was validated to be smooth and reasonable, and could meet the requirements of finite element analysis. The method is not merely applied to reconstruct the geometric model of the cervical spine. It is a way to construct the model of the skeletal system of the human body.


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