Mathematical Modelling for Micropiles Embedded in Salt Rock

Abstract This study presents the results of the mathematical modelling for the micropiles foundation of an investement objective located in Slanic, Prahova county. Three computing models were created and analyzed with software, based on Finite Element Method. With Plaxis 2D model was analyzed the isolated micropile and the three-dimensional analysis was made with Plaxis 3D model, for group of micropiles. For the micropiles foundation was used Midas GTS-NX model. The mathematical models were calibrated based with the in-situ tests results for axially loaded micropiles, embedded in salt rock. The paper presents the results obtained with the three software, the calibration and validation models.

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Fetal weight estimation by automated three-dimensional limb volume model in late third trimester compared to two-dimensional model: a cross-sectional prospective observational study

10.21203/rs.3.rs-271271/v1 ◽

2021 ◽

Author(s):

Xining Wu ◽

Zihan Niu ◽

Zhonghui Xu ◽

Yuxin Jiang ◽

Yixiu Zhang ◽

...

Keyword(s):

Birth Weight ◽

3D Model ◽

Three Dimensional ◽

Fetal Weight ◽

Percentage Error ◽

Limb Volume ◽

Third Trimester ◽

Volume Model ◽

Estimated Error ◽

2D Model

Abstract Background: Accurate estimation of fetal weight is important for prenatal care and for detection of fetal growth abnormalities. Prediction of fetal weight entails the indirect measurement of fetal biometry by ultrasound that is then introduced into formulae to calculate the estimated fetal weight. The aim of our study was to evaluate the accuracy of the automated three-dimensional(3D) fractional limb volume model to predict fetal weight in the third trimester.Methods: Prospective 2D and 3D ultrasonography were performed among women with singleton pregnancies 7 days before delivery to obtain 2D data, including fetal biparietal diameter, abdominal circumference and femur length, as well as 3D data, including the fractional arm volume (AVol) and fractional thigh volume (TVol). The fetal weight was estimated using the 2D model and the 3D fractional limb volume model respectively. Percentage error = (estimated fetal weight - actual birth weight) ÷ actual birth weight × 100. Systematic errors (accuracy) were evaluated as the mean percentage error (MPE). Random errors (precision) were calculated as±1 SD of percentage error.Results: Ultrasound examination was performed on 56 fetuses at 39.6 ± 1.4 weeks gestation. The average birth weight of the newborns was 3393 ± 530 g. The average fetal weight estimated by the 2D model was 3478 ± 467 g, and the MPE was 3.2 ± 8.9. The average fetal weights estimated by AVol and TVol of the 3D model were 3268 ± 467 g and 3250 ± 485 g, respectively, and the MPEs were -3.3 ± 6.6 and -3.9 ± 6.1, respectively. For the 3D TVol model, the proportion of fetuses with estimated error ≤ 5% was significantly higher than that of the 2D model (55.4% vs. 33.9%, p < 0.05). For fetuses with a birth weight < 3500 g, the accuracy of the AVol and TVol models were better than the 2D model (-0.8 vs. 7.0 and -2.8 vs. 7.0, both p < 0.05). Moreover, for these fetus, the proportions of estimated error ≤ 5% of the AVol and TVol models were 58.1% and 64.5%, respectively, significantly higher than that of the 2D model (19.4%) (both p < 0.05). The consistency of different examiners measuring fetal AVol and TVol were satisfactory,with the intraclass correlation coefficients of 0.921 and 0.963, respectively.Conclusion: In this cohort,the automated 3D fractional limb volume model improves the accuracy of weight estimation in most third-trimester fetuses. In particular, the 3D model estimation accuracy for fetuses with weight < 3500 g is significantly higher than that of the traditional 2D model.

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Influence of Electric Field Coupling Model on the Simulated Performances of a GaN Based Planar Nanodevice

Journal of Nanomaterials ◽

10.1155/2013/124354 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 14

Author(s):

K. Y. Xu ◽

Z. N. Wang ◽

Y. N. Wang ◽

J. W. Xiong ◽

G. Wang

Keyword(s):

Electric Field ◽

3D Model ◽

Second Harmonic ◽

Strong Electric Field ◽

Three Dimensional ◽

Harmonic Oscillation ◽

Two Dimensional ◽

Dc Bias ◽

Simulation Results ◽

2D Model

The performances of a two-dimensional electron gas (2DEG) based planar nanodevice are studied by a two-dimensional-three-dimensional (2D-3D) combined model and an entirely 2D model. In both models, 2DEGs are depicted by 2D ensemble Monte Carlo (EMC) method. However electric field distributions in the devices are obtained by self-consistently solving 2D and 3D Poisson equations for the 2D model and the 2D-3D model, respectively. Simulation results obtained by both models are almost the same at low bias while showing distinguished differences at high bias. The 2D model predicts larger output current and slightly higher threshold voltage of Gunn oscillations. Although the fundamental frequencies of current oscillations obtained by both models are similar, the deviation of wave shape from sinusoidal waveform obtained by the 2D model is more serious than that obtained by 2D-3D model. Moreover, results obtained by the 2D model are more sensitive both to the bias conditions and to the change of device parameters. Interestingly, a look-like second harmonic oscillation has been observed at DC bias. We contribute the origin of divergences in simulation results to the different coupling path of electric field in the two models. And the second-harmonic oscillations at DC bias should be the result of the appearance of concomitant oscillations beside the channel excited by strong electric-field effects.

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On the Two-Dimensional Simplification of Three-Dimensional Cementless Hip Stem Numerical Models

Journal of Biomechanical Engineering ◽

10.1115/1.4035368 ◽

2017 ◽

Vol 139 (3) ◽

Cited By ~ 2

Author(s):

Fernando J. Quevedo González ◽

Michael Reimeringer ◽

Natalia Nuño

Keyword(s):

Cortical Thickness ◽

Variable Thickness ◽

3D Model ◽

Numerical Models ◽

Computational Cost ◽

Three Dimensional ◽

Symmetry Plane ◽

Stair Climbing ◽

Side Plate ◽

2D Model

Three-dimensional (3D) finite element (FE) models are commonly used to analyze the mechanical behavior of the bone under different conditions (i.e., before and after arthroplasty). They can provide detailed information but they are numerically expensive and this limits their use in cases where large or numerous simulations are required. On the other hand, 2D models show less computational cost, but the precision of results depends on the approach used for the simplification. Two main questions arise: Are the 3D results adequately represented by a 2D section of the model? Which approach should be used to build a 2D model that provides reliable results compared to the 3D model? In this paper, we first evaluate if the stem symmetry plane used for generating the 2D models of bone-implant systems adequately represents the results of the full 3D model for stair climbing activity. Then, we explore three different approaches that have been used in the past for creating 2D models: (1) without side-plate (WOSP), (2) with variable thickness side-plate and constant cortical thickness (SPCT), and (3) with variable thickness side-plate and variable cortical thickness (SPVT). From the different approaches investigated, a 2D model including a side-plate best represents the results obtained with the full 3D model with much less computational cost. The side-plate needs to have variable thickness, while the cortical bone thickness can be kept constant.

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Comparison of Two-Dimensional and Three-Dimensional Thermal Models of the LENS® Process

Journal of Heat Transfer ◽

10.1115/1.2953236 ◽

2008 ◽

Vol 130 (10) ◽

Cited By ~ 14

Author(s):

H. Yin ◽

L. Wang ◽

S. D. Felicelli

Keyword(s):

Thermal Behavior ◽

Molten Pool ◽

3D Model ◽

Dynamic Control ◽

Three Dimensional ◽

Element Model ◽

Two Dimensional ◽

3D Effects ◽

Net Shaping ◽

2D Model

A new two-dimensional (2D) transient finite element model was developed to study the thermal behavior during the multilayer deposition by the laser engineered net shaping rapid fabrication process. The reliability of the 2D model was evaluated by comparing the results obtained from the 2D model with those computed by a previously developed three-dimensional (3D) model. It is found that the predicted temperature distributions and the cooling rates in the molten pool and its surrounding area agree well with the experiment data available in literature and with the previous results calculated with the 3D model. It is also concluded that, for the geometry analyzed in this study, the 2D model can be used with good accuracy, instead of the computationally much more expensive 3D model, if certain precautions are taken to compensate for the 3D effects of the substrate. In particular, a 2D model could be applied to an in situ calculation of the thermal behavior of the deposited part during the fabrication, allowing dynamic control of the process. The 2D model is also applied to study the effects of substrate size and idle time on the thermal field and size of the molten pool.

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In Situ Lateral Load Tests on Instrumented Bored Piles in Loessial Soils

Mathematical Modelling in Civil Engineering ◽

10.1515/mmce-2017-0001 ◽

2017 ◽

Vol 13 (1) ◽

pp. 1-11

Author(s):

Sebastian Drăghici ◽

Anatolie Marcu

Keyword(s):

Large Diameter ◽

In Situ Tests ◽

Laterally Loaded Piles ◽

Natural Moisture Content ◽

Load Tests ◽

Bored Piles ◽

Strength And Stiffness ◽

Laterally Loaded ◽

Plaxis 3D

Abstract The aim of the paper is to provide some aspects regarding the behaviour of laterally loaded piles in loessial soils, by presenting and analysing the results of several in situ tests on large diameter bored piles in this type of soil. The major feature of loess is that it exhibits a massive decline of its strength and stiffness parameters when it comes into contact with water, leading to the collapse of its structure even under self-weight and creating difficult conditions for foundations. The load tests were performed both in natural moisture content loess and also in saturated loess. The results obtained by means of instrumentation are back-analysed using current analytical methods and also by finite element method using a numerical model in the geotechnical computation software Plaxis 3D.

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A comparison of a two-dimensional depth averaged flow model and a three-dimensional RANS model for predicting tsunami inundation and fluid forces

10.5194/nhess-2018-150 ◽

2018 ◽

Cited By ~ 1

Author(s):

Xinsheng Qin ◽

Michael Motley ◽

Randall LeVeque ◽

Frank Gonzalez ◽

Kaspar Mueller

Keyword(s):

Built Environment ◽

3D Model ◽

Computational Cost ◽

Three Dimensional ◽

Vertical Direction ◽

3D Models ◽

Tsunami Inundation ◽

Model Based ◽

Fine Mesh ◽

2D Model

Abstract. The numerical modeling of tsunami inundation that incorporates the built environment of coastal communities is challenging for both depth-integrated 2D and 3D models, not only in modeling the flow, but also in predicting forces on coastal structures. For depth-integrated 2D models, inundation and flooding in this region can be very complex with variation in the vertical direction caused by wave breaking on shore and interactions with the built environment and the model may not be able to produce enough detail. For 3D models, a very fine mesh is required to properly capture the physics, dramatically increasing the computational cost and rendering impractical the modeling of some problems. In this paper, comparisons are made between GeoClaw, a depth-integrated 2D model based on the nonlinear shallow water equations (NSWE), and OpenFOAM, a 3D model based on Reynolds Averaged Navier-Stokes (RANS) equation for tsunami inundation modeling. The two models were first validated against existing experimental data of a bore impinging onto a single square column. Then they were used to simulate tsunami inundation of a physical model of Seaside, Oregon. The resulting flow parameters from the models are compared and discussed, and these results are used to extrapolate tsunami-induced force predictions. It was found that the 2D model did not accurately capture the important details of the flow near initial impact due to the transiency and large vertical variation of the flow. Tuning the drag coefficient of the 2D model worked well to predict tsunami forces on structures in simple cases but this approach was not always reliable in complicated cases. The 3D model was able to capture transient characteristic of the flow, but at a much higher computational cost; it was found this cost can be alleviated by subdividing the region into reasonably sized subdomains without loss of accuracy in critical regions.

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A Novel in Situ Stress Monitoring Technique for Fracture Rock Mass and Its Application in Deep Coal Mines

Applied Sciences ◽

10.3390/app9183742 ◽

2019 ◽

Vol 9 (18) ◽

pp. 3742 ◽

Cited By ~ 2

Author(s):

Bin Liu ◽

Yuanguang Zhu ◽

Quansheng Liu ◽

Xuewei Liu

Keyword(s):

Rock Mass ◽

Coal Mines ◽

Three Dimensional ◽

In Situ Stress ◽

Hole Drilling ◽

Stress Monitoring ◽

Underground Engineering ◽

In Situ Tests ◽

Monitoring Method

A novel in situ stress monitoring method, based on rheological stress recovery (RSR) theory, was proposed to monitor the stress of rock mass in deep underground engineering. The RSR theory indicates that the tiny hole in the rock can close gradually after it was drilled due to the rheology characteristic, during which process the stress that existed in the rock can be monitored in real-time. Then, a three-dimensional stress monitoring sensor, based on the vibrating wire technique, was developed for in field measurement. Furthermore, the in-field monitoring procedures for the proposed technique are introduced, including hole drilling, sensor installation, grouting, and data acquisition. Finally, two in situ tests were carried out on deep roadways at the Pingdingshan (PDS) No. 1 and No. 11 coal mines to verify the feasibility and reliability of the proposed technique. The relationship between the recovery stress and the time for the six sensor faces are discussed and the final stable values are calculated. The in situ stress components of rock masses under geodetic coordinates were calculated via the coordinate transformation equation and the results are consistent with the in situ stress data by different methods, which verified the effectiveness of the proposed method.

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Assessment of human-induced vibrations of a cable-stayed footbridge

MATEC Web of Conferences ◽

10.1051/matecconf/201821109001 ◽

2018 ◽

Vol 211 ◽

pp. 09001 ◽

Cited By ~ 1

Author(s):

Izabela Drygała ◽

Joanna M. Dulinska ◽

Marek Wazowski

Keyword(s):

Natural Frequencies ◽

Dynamic Properties ◽

Three Dimensional ◽

Fe Model ◽

In Situ Tests ◽

Modal Assurance Criterion ◽

Comfort Criteria ◽

Abaqus Software

The primary purpose of this research is the evaluation of human-induced vibrations of a cable-stayed footbridge. The cable-stayed pedestrian bridge with total length of the span equal to 46.90 m located in Czestochowa (Southern Poland) was chosen as a case study. The footbridge consists of two spans (21.10 m and 25.80 m). A three-dimensional (3D) finite element (FE) model of the footbridge was prepared with the ABAQUS software program. The dynamic properties of the structure, i.e. its natural frequencies, modes shapes and damping ratios, were estimated on the basis of the in situ tests results as well as numerical analysis. For the validation of the modal models the modal assurance criterion (MAC) theory was applied. In the next stage of the investigation the dynamic response of the structure to human-induced loading was evaluated. Finally, the vibration comfort criteria for the footbridge were checked.

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Dynamic structural parameters verification on the example of theoretical analysis and in situ tests of suspension footbridge

MATEC Web of Conferences ◽

10.1051/matecconf/201926210007 ◽

2019 ◽

Vol 262 ◽

pp. 10007

Author(s):

Michał Jukowski ◽

Ewa Błazik-Borowa ◽

Jarosław Bęc ◽

Janusz Bohatkiewicz

Keyword(s):

Structural Parameters ◽

Rapid Development ◽

Three Dimensional ◽

Nonlinear Material ◽

Structural Elements ◽

In Situ Tests ◽

Engineering Structures ◽

Material Models ◽

Three Dimensional Models

The 21st century is a period of rapid development of computer technology, which allowed designers to create complex, three-dimensional models of engineering structures. Thanks to these solutions, it is possible to perform complex analyses, for example modal or dynamic ones of cable-stayed or suspension structures. For such objects, verification of the correct work of structural elements takes place in the field of non-linear analysis. The presented paper is an example of a comparative analysis concerning modal and static analysis - Natural Frequency with Nonlinear Material Models and Static Stress with Nonlinear Material Models, carried out in the Autodesk Simulation Multiphysics program with dynamic in situ tests of a suspension footbridge. The main purpose of the research was to evaluate the value of pre-tension forces in the cables of the load-bearing structure.

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Numerical Simulation of Three-Dimensional Dendrite Movement Based on the CA–LBM Method

Crystals ◽

10.3390/cryst11091056 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1056

Author(s):

Qi Wang ◽

Yingming Wang ◽

Shijie Zhang ◽

Binxu Guo ◽

Chenyu Li ◽

...

Keyword(s):

3D Model ◽

Three Dimensional ◽

Solidification Process ◽

Movement Direction ◽

Liquid Boundary ◽

Alloy Microstructure ◽

The Difference ◽

Boltzmann Method ◽

Solid Liquid ◽

2D Model

At present, the calculation of three-dimensional (3D) dendrite motion using the cellular automata (CA) method is still in its infancy. In this paper, a 3D dendrite motion model is constructed. The heat, mass, and momentum transfer process in the solidification process of the alloy melt are calculated using a 3D Lattice–Boltzmann method (LBM). The growth process for the alloy microstructure is calculated using the CA method. The interactions between dendrites and the melt are assessed using the Ladd method. The solid–liquid boundary of the solute field in the movement process is assessed using the solute extrapolation method. The translational velocity of the equiaxed crystals in motion is calculated using the classical mechanical law. The rationality of the model is verified and the movement of single and multiple 3D equiaxed crystals is simulated. Additionally, the difference between 3D dendrite movement and two-dimensional (2D) dendrite movement is analyzed. The results demonstrate that the growth of moving dendrites is asymmetric. The growth velocity and falling velocity of the dendrite in the 3D model are faster than that in 2D model, while the simulation result is more realistic than that of the 2D model. When multiple dendrites move, the movement direction of the dendrites will change due to the merging of flow fields and other factors.

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