Three-dimensional numerical investigation of multifaced tunneling in water-bearing soft ground

2008 ◽  
Vol 45 (10) ◽  
pp. 1467-1486 ◽  
Author(s):  
Chungsik Yoo ◽  
Sun-Bin Kim
Keyword(s):  
Numerical Investigation ◽  
Three Dimensional ◽  
Element Model ◽  
Soft Ground ◽  
Single Pile ◽  
Ground Settlement ◽  
Axial Loads ◽  
Groundwater Drawdown ◽  
Fully Coupled ◽  
Ground Settlements

This paper presents the results of a numerical investigation of the performance of multifaced tunneling under a pile-supported building in water-bearing soft ground. Special attention was paid to the effect of tunneling and groundwater interaction on the tunneling performance. A fully coupled three-dimensional (3D) stress – pore pressure finite element model was adopted to realistically capture the mechanical and hydrological interaction between the tunneling and groundwater. The results indicate that the groundwater drawdown during tunneling yields a considerably larger settlement-affected zone than for cases with no groundwater drawdown, with a tendency for large portions of ground settlement and groundwater drawdown to be completed before the tunnel passes a monitoring section. Also revealed is that the presence of a building tends to reduce the ground settlements and cause subsurface settlements more or less uniformly with depth. It is shown that the lining deformation, and thus its stresses are not significantly affected by the presence of the building for the multifaced tunneling considered in this study. Axial loads in the piles supporting the building tend to either increase or decrease depending on the pile location relative to the tunnel axis. The patterns of changes in pile axial loads are different from the results of previous studies concerning a single pile.

Fully coupled seakeeping, slamming, and whipping calculations

2009 ◽  
Vol 223 (3) ◽  
pp. 439-456 ◽  
Author(s):  
J T Tuitman ◽  
Š Malenica
Keyword(s):  
Linear Time ◽  
Three Dimensional ◽  
Bending Moment ◽  
Fatigue Loading ◽  
Element Model ◽  
Beam Model ◽  
Full Wave ◽  
Elastic Modes ◽  
Large Container ◽  
Fully Coupled

This paper presents a methodology to solve the seakeeping, slamming, and whipping problems coupled within a single calculation. The coupled problem is solved within a partly non-linear time domain seakeeping program. The elastic modes used in this hydroelastic problem can be calculated using a beam model or full three-dimensional (3D) finite element model of the ship structure. The slamming loading is calculated by a two-dimensional (2D) method. The main focus of this paper is the creation of an accurate and consistent coupling between the 3D seakeeping program and the 2D slamming calculation. Differences in timescale and integration methods make this coupling complex. A large container ship is used to illustrate the application of the presented methodology. The contribution of the non-linearities and the whipping response to the expected maximum bending moment and fatigue damage of this ship for a full-wave scatter diagram is calculated. The results show that the slamming-induced whipping response has a significant contribution to both the ultimate bending moment and the fatigue loading of the ship.

Numerical Simulation of Post-Construction Deformation Characteristics of Storage Oil Tank Ground

2013 ◽  
Vol 353-356 ◽  
pp. 593-596 ◽  
Author(s):  
Yan Mei Zhang ◽  
Xu Dong Zhang
Keyword(s):  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Ground Deformation ◽  
Water Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Additional Stress ◽  
Soil Parameters ◽  
Ground Settlement ◽  
Constrained Modulus

Ground soil was looked as porous medium, a three-dimensional finite element model of shell-liquid-foundation-ground was built, and the influence of soil parameters, filling liquid mode, and liquid height on the tank ground deformation was discussed. The research shows that the subsidence range caused by additional stress is the 0.3D range of the tank bottom edge outer; the influence of soil constrained modulus on settlement is remarkable, with constrained modulus decreasing, the tank ground settlement increases; with soil permeability coefficient decreasing, the tank ground settlement decreases; the ground settlement curve shape is decided by soil constrained modulus and permeability coefficient; the influence of filling liquid mode on the ground final settlement is very small ,but on the pore water pressure peak is remarkable.

Numerical investigation on the effect of welding speed and heat input on the residual stress of multi-pass TIG welded stainless steel pipe

2020 ◽  
pp. 095440542098133
Author(s):  
Parviz Asadi ◽  
Samaneh Alimohammadi ◽  
Omid Kohantorabi ◽  
Ali Soleymani ◽  
Ali Fazli
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Numerical Investigation ◽  
Welding Speed ◽  
Heat Input ◽  
Three Dimensional ◽  
Welding Process ◽  
Element Model ◽  
Stress States ◽  
Three Dimensional Finite Element

A numerical investigation is provided to study the residual stress states in multi-pass TIG welding of stainless steel SUS304 pipe. An uncoupled thermomechanical three-dimensional finite element model is developed using the ABAQUS software for a circular weld design around the pipe. The effects of weld pass numbers, electrode moving speed, and heat input on the internal and external surface tensions of the pipe are investigated. The simulation results show that by increasing the welding speed, the axial tensile stresses decrease on the pipe surfaces. In the case of hoop stress, as the welding speed raises, the tensile and compressive stresses are increased for both two- and three-pass welding. However, the width of the stress zone becomes narrower in higher welding speeds. The hoop stresses, in comparison with the axial stresses, are more strongly influenced by the welding speed and the heat input. Furthermore, using the three-pass welding process results in much lower stresses in comparison with the two-pass one.

Rotordynamic Analysis of a Large Industrial Turbo-Compressor Including Finite Element Substructure Modeling

2006 ◽  
Author(s):  
J. Jeffrey Moore ◽  
Giuseppe Vannini ◽  
Massimo Camatti ◽  
Paolo Bianchi
Keyword(s):  
Finite Element ◽  
Transfer Function ◽  
Transfer Functions ◽  
Three Dimensional ◽  
Coupled Model ◽  
Element Model ◽  
7Th Edition ◽  
Curve Fit ◽  
Turbo Compressor ◽  
Fully Coupled

A rotordynamic analysis of a large turbo-compressor that models both the casing and supports along with the rotor-bearing system was performed. A three-dimensional (3-D) finite element model of the casing captures the intricate details of the casing and support structure. Two approaches are presented, including development of transfer functions of the casing and foundation, as well as a fully coupled rotor-casing-foundation model. The effect of bearing support compliance is captured, as well as the influence of casing modes on the rotor response. The first approach generates frequency response functions (FRF’s) from the finite element case model at the bearing support locations. A high-order polynomial in numerator-denominator transfer function format is generated from a curve-fit of the FRF. These transfer functions are then incorporated into the rotordynamics model. The second approach is a fully coupled rotor and casing model that is solved together. An unbalance response calculation is performed in both cases to predict the resulting rotor critical speeds and response of the casing modes. The effect of the compressor case and supports caused the second critical speed to drop to a value close to the operating speed and not compliant with API 617 7th edition requirements. A combination of rotor, journal bearing, casing, and support modifications resulted in a satisfactory and API compliant solution. The results of the fully coupled model validated the transfer function approach.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

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.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

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.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

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.

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