scholarly journals The Deformation Analysis of a Deep Frame Top-Down Excavation in Downtown Shanghai Based on the 3D FEM

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ting Bai ◽  
Dong Xie
Keyword(s):  
Environmental Influence ◽  
Soft Clay ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Deformation Analysis ◽  
Deep Excavation ◽  
Top Down ◽  
3D Fem ◽  
Qualitative Comparison ◽  
Construction Methods

The deformation and environmental influence of the pit excavation in downtown is very important. A 3D FEM analysis is conducted to understand the deformation of a 13.9 to 15.2 m deep excavation with an in-plane dimension of about 189 m width and 251 m length constructed by the frame top-down method (FTDM) in the soft clay region in the Shanghai metropolitan area. The field monitoring results indicate that the magnitudes of wall deflections and ground settlements, along with the column’s uplift difference, are relatively small, which are below the specified protection levels, and that the FTDM is feasible as one of the extralarge excavation construction methods. It is reasonable to predict wall deflection by 3D FEM simulation with qualitative comparison between the simulated column uplifts and the measured data, yet the prediction of the settlement distribution is of no satisfaction. This project studied in this paper not only serves as a special case study calibrated and verified by numerical tools but also provides insights into the design and construction of an extralarge deep excavation using the frame top-down method in soft soils and metropolitan environment.

FEM Simulation of an Elliptical-Shaped Corrugated Steel Culvert Pipe for Highway Construction

2011 ◽  
Vol 71-78 ◽  
pp. 1613-1616
Author(s):  
Feng Yue ◽  
Xue Jun Wen
Keyword(s):  
Highway Construction ◽  
Fem Simulation ◽  
Fem Analysis ◽  
High Strength ◽  
Cost Effective ◽  
Steel Plates ◽  
3D Fem ◽  
Environment Friendly ◽  
Rapid Construction ◽  
Backfill Soil

In this paper, we discuss the design and calculation methods of elliptical-shaped corrugated steel culvert pipe (ECSCP) used in highway construction. With many advantages such as lightweight, environment friendly, cost-effective, rapid construction, etc., corrugated steel culvert pipe (CSCP) have been widely used in highway construction acting as the alternative of RC culvert in China in recent years. The ECSCP in this paper is a kind of culvert which is fabricated to an elliptical shape with several pieces of corrugated steel plates which are jointed by high strength bolts. This study is conducted on the basis of the ECSCP used in the construction of Shanghai North Outer Ring Line Highway in China. 3D FEM analysis is performed considering several parameters such as modulus of elasticity of the surrounding backfill soil, length of major and minor axis of elliptical-shaped section, eccentricity of vehicles. Some design methods are proposed in this paper, and they will be useful guidelines for safe design of ECSCP.

FEM Analysis for the Influence of Manufacturing Process Defects on Dynamic Behavior of Thin Chromium Microbeam

2014 ◽  
Vol 548-549 ◽  
pp. 958-962 ◽  
Author(s):  
H. Bourouina ◽  
R. Yahiaoui ◽  
B.Y. Majlis ◽  
A. Hassein-Bey ◽  
M.E.A. Benamar ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Behavior ◽  
Manufacturing Process ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Analytical Models ◽  
3D Fem ◽  
Thin Chromium ◽  
Technological Defects

This paper identifies and investigates the influence of technological defects of manufacturing process on the dynamic behavior of thin chromium microbeam. The analytical models will be analyzed and corrected using finite element method (FEM) to determine their validity under influence of technological defects. A semi-analytical model will be proposed for the extraction of corrective factors from 3D FEM simulation of dynamic behavior of microbeam. Final results indicate that the correction of technological defects is very significant for Cr microbeam 80x2x0.95μm3. In other hand, the corrected value of Young’s modulus is very close to the experimental results and it is about 279.1GPa.

scholarly journals Penggunaan Dinding Silang Pada Galian Dalam Di Tanah Sangat Lunak: Studi Kasus Proyek Apartemen DI Jalan Kebun Sirih Jakarta

2020 ◽  
Vol 4 (2) ◽  
pp. 257
Author(s):  
Oktaffian Widjaja ◽  
Chaidir Anwar Makarim
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Soft Clay ◽  
Good Choice ◽  
Cross Wall ◽  
Deep Excavation ◽  
Top Down ◽  
Adjacent Buildings ◽  
Clay Deposits ◽  
Lateral Resistance

Deep excavation in areas with very soft clay deposits need a good soil retaining system and excavation method. Using a diapraghm wall as a soil retaining system for deep excavation is a good choice can be done. Diapraghm wall is expected to limit the movement that occurs in the retaining walls and avoid leaks that occur in walls, this is needed to minimize damage to adjacent buildings. The top down excavation method by utilizing the basement floor as lateral resistance can be carried out to reduce the movement that occurs on the ground. In very soft soil areas with excavation distances to neighbors very close, the movement on the ground must be limited to minimize damage to adjacent buildings. Cross walls can be used to reduce the movement that occurs on the ground. Analysis of finite element with using the Plaxis program was carried out to investigate the performance of the retaining wall. From the results of the analysis conducted shows that using a cross wall at a location below the raft pile can be reduced the movement that occurs in the retaining wall and the excavation stages can be reduced. Keywords: cross wall; deep excavation; diapraghm wall; very soft soil ABSTRAKGalian dalam pada daerah dengan endapan tanah liat sangat lunak yang cukup dalam diperlukan sistem penahan tanah dan metode galian yang direncanakan dengan baik. Menggunakan dinding dipraghm sebagai sistem penahan tanah untuk galian dalam merupakan pilihan yang dapat dilakukan. Penggunaan dinding diapraghm diharapkan dapat membatasi pergerakan yang terjadi pada dinding dan menghindari kebocoran yang yang terjadi pada dinding penahan tanah karena sistem pengecoran yang saling mengunci dan pertemuan antara panel dinding dapat dipasang waterstop, hal ini diperlukan untuk menghindari kerusakan pada bangunan yang berdekatan dengan daerah galian. Metode galian top down yaitu galian bertahap dengan memanfaatkan lantai besmen sebagai tahanan lateral dapat dilakukan untuk mengurangi pergerakan yang terjadi pada tanah. Pada daerah tanah sangat lunak dengan jarak galian dengan tetangga sangat berdekatan pergerakan pada tanah harus dibatasi untuk meminimalkan kerusakan pada bangunan yang berdekatan. Dinding silang merupakan sistem tahanan lateral yang dapat dipergunakan untuk mengurangi pergerakan yang terjadi pada tanah. Analisis elemen hingga menggunakan program Plaxis 2D dilakukan untuk mengetahui kinerja dinding penahan tanah dan pergerakan yang terjadi. Dari hasil analisis yang dilakukan diperoleh hasil bahwa dengan menggunakan dinding silang yang terletak pada di bawah raft pile dapat menurunkan pergerakan yang terjadi pada dinding penahan tanah dan tahapan galian dapat dikurangi. 

scholarly journals Design and construction of a deep excavation in soft soils adjacent to the Shanghai Metro tunnels

2003 ◽  
Vol 40 (5) ◽  
pp. 933-948 ◽  
Author(s):  
Z F Hu ◽  
Z Q Yue ◽  
J Zhou ◽  
L G Tham
Keyword(s):  
Ground Improvement ◽  
Soft Soil ◽  
Soft Clay ◽  
Theoretical Method ◽  
Horizontal Displacement ◽  
Deep Excavation ◽  
Construction Methods ◽  
Diaphragm Walls ◽  
Shanghai Metro ◽  
Design And Construction

This paper presents the design and construction of a deep excavation for building foundations in saturated soil. This deep excavation was of particular interest because it was located above and beside the Shanghai Metro tunnels. The twin Shanghai Metro tunnels had to be in full operation during the deep excavation. Potential large deformation of the twin tunnels was one of the main concerns during the design and construction for the deep excavation. The paper discusses in detail the criteria and measures for controlling the soil and tunnel deformation. The measures included cast-in-place concrete diaphragm walls with bracing structural members, pumping consolidation, cement–soil mix pile systems, and rational excavation procedures. A simplified theoretical method was proposed to estimate the increment in undrained shear strength in a soft clay layer due to pumping consolidation. Furthermore, conventional finite element methods were used to predict the soil vertical and horizontal displacements induced by the excavation. Using the design and construction methods discussed in the paper, the settlement and horizontal displacement of the tunnels were successfully controlled within 5.0 mm and 9.0 mm, respectively. The curvature of longitudinal deformation curve of the tunnels was less than 1/15 000. The horizontal displacement of the braced diaphragm walls was less than 0.12% of the total excavation depth. Key words: Metro tunnels, saturated soft soil, deep excavation, design, construction, ground improvement, case studies.

scholarly journals Capabilities of Using Fem in Sheet-Metal Forming

2016 ◽  
Vol 61 (2) ◽  
pp. 947-951
Author(s):  
S. Korga ◽  
A. Duda ◽  
Z. Ciekanowski
Keyword(s):  
Research Methods ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Operating Conditions ◽  
Deformation Analysis ◽  
Plastic Processing ◽  
Metal Deformation

Abstract The aim of this study was to determine and select boundary conditions of modeling and FEM simulation for plastic processing on the example of sheet-metal forming. For sheet-metal deformation analysis, Deform 3D has been used. The study presents research methods for real and virtual conditions. There are also described common features and these differentiating obtained results. Research of conducted process of sheet-metal forming allows to determine the effectiveness of computer research methods. The finite-element method can be used as an effective tool for the study of plastic processing phenomena considering various operating conditions of individual elements provided the appropriate tools for FEM analysis.

Design, 3D FEM Simulation and Prototyping of a Permanent Magnet Spherical Motor

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 305
Author(s):  
Umut Yusuf Gündoğar ◽  
Sibel Zorlu Zorlu Partal
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Tilt Angle ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Magnetic Flux Density ◽  
3D Fem ◽  
Spherical Motor

In recent years, large tilt angles, uniform magnetic flux distributions, strong forces, and large torques for motors have increasingly become important for robotics, biomedical, and automotive applications that have multi-degrees of freedom (MDOFs) motion. Generally, one-degree of-freedom motors are applied in MDOF motion. These situations cause the systems to have very complex and large structures. In order to address these issues, a 2-DOF surface permanent magnet spherical motor with a new mechanical design for the movement of the rotor with a large tilt angle of ±45° was designed, simulated, produced and tested in this paper. The motor consisted of a 4-pole permanent magnet rotor and a 3-block stator with 18 coils. In this study, the mechanical structure of the proposed spherical permanent magnet motor surrounded the rotor with two moving parts to move at a large tilt angle of ±45° without using any mechanical components such as spherical bearings, joint bearings, and bearing covers. Thus, the tilt angle, force, and torque values of the proposed motor have been improved according to MDOF motion motors using spherical bearings, bearing covers, or joint bearings in their mechanical structures in the literature. Ansys Maxwell software was used for the design and simulation of the motor. Three-dimensional (3D) finite element method (FEM) analysis and experimental studies were carried out on the force, torque, and magnetic flux density distribution of the motor. Then, simulation results and experimental results were compared to validate the 3D FEM simulations results.

scholarly journals 3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4450 ◽  
Author(s):  
Wenjuan Liu ◽  
Leming He ◽  
Xubo Wang ◽  
Jia Zhou ◽  
Weijiang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Electrical Impedance ◽  
Fem Simulation ◽  
Laser Doppler Vibrometer ◽  
Fem Analysis ◽  
3D Models ◽  
Passive Layer ◽  
Mode Shapes ◽  
3D Fem ◽  
Resonant Frequencies

This paper presents three-dimensional (3D) models of high-frequency piezoelectric micromachined ultrasonic transducers (PMUTs) based on the finite element method (FEM). These models are verified with fabricated aluminum nitride (AlN)-based PMUT arrays. The 3D numerical model consists of a sandwiched piezoelectric structure, a silicon passive layer, and a silicon substrate with a cavity. Two types of parameters are simulated with periodic boundary conditions: (1) the resonant frequencies and mode shapes of PMUT, and (2) the electrical impedance and acoustic field of PMUT loaded with air and water. The resonant frequencies and mode shapes of an electrically connected PMUT array are obtained with a laser Doppler vibrometer (LDV). The first resonant frequency difference between 3D FEM simulation and the measurement for a 16-MHz PMUT is reasonably within 6%, which is just one-third of that between the analytical method and the measurement. The electrical impedance of the PMUT array measured in air and water is consistent with the simulation results. The 3D model is suitable for predicting electrical and acoustic performance and, thus, optimizing the structure of high-frequency PMUTs. It also has good potential to analyze the transmission and reception performances of a PMUT array for future compact ultrasonic systems.

scholarly journals 3D-FEM Simulation of Hot Rolling Process and Characterization of the Resultant Microstructure of a Light-Weight Mn Steel

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 569
Author(s):  
Ana Claudia González-Castillo ◽  
José de Jesús Cruz-Rivera ◽  
Mitsuo Osvaldo Ramos-Azpeitia ◽  
Pedro Garnica-González ◽  
Carlos Gamaliel Garay-Reyes ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Thermomechanical Processing ◽  
Computational Simulation ◽  
Effective Strain ◽  
Fem Simulation ◽  
Rolling Process ◽  
3D Fem ◽  
Hot Rolling Process ◽  
Mn Steel

Computational simulation has become more important in the design of thermomechanical processing since it allows the optimization of associated parameters such as temperature, stresses, strains and phase transformations. This work presents the results of the three-dimensional Finite Element Method (FEM) simulation of the hot rolling process of a medium Mn steel using DEFORM-3D software. Temperature and effective strain distribution in the surface and center of the sheet were analyzed for different rolling passes; also the change in damage factor was evaluated. According to the hot rolling simulation results, experimental hot rolling parameters were established in order to obtain the desired microstructure avoiding the presence of ferrite precipitation during the process. The microstructural characterization of the hot rolled steel was carried out using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the phases present in the steel after hot rolling are austenite and α′-martensite. Additionally, to understand the mechanical behavior, tensile tests were performed and concluded that this new steel can be catalogued in the third automotive generation.

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