scholarly journals Numerical Investigation on Steel Square HSS Columns Strengthened with Polymer-mortar

2019 ◽  
pp. 1-25
Author(s):  
Khaled M. El-Sayed ◽  
Ahmed S. Debaiky ◽  
Nader N. Khalil ◽  
Ibrahim M. El-Shenawy
Keyword(s):  
Three Dimensional ◽  
Shell Element ◽  
Fe Analysis ◽  
Experimental Results ◽  
Fe Model ◽  
Cross Sectional ◽  
Axial Strength ◽  
Polymer Mortar ◽  
Slender Columns ◽  
Good Agreement

This paper presents the results of finite element (FE) analysis of axially loaded square hollow structural steel (HSS) columns, strengthened with polymer-mortar materials. Three-dimensional nonlinear FE model of HSS slender columns were developed using thin-shell element, considering geometric and material nonlinearity. The polymer-mortar strengthening layer was incorporated using additional layers of the shell element. The FE model has been performed and then verified against experimental results obtained by the authors [1]. Good agreement was observed between FE analysis and experimental results. The model was then used in an extended parametric study to examine selected AISC square HSS columns with different cross-sectional geometries, slenderness ratios, thicknesses of mortar strengthening layer, overall geometric imperfections, and level of residual stresses. The effectiveness of polymer-mortar in increasing the column’s axial strength is observed. The study also demonstrated that polymer-mortar strengthening materials is more effective for higher slenderness ratios. An equivalent steel thickness is also accounted for the mortar strengthened HSS columns to discuss the effectiveness of polymer-mortar strengthening system. The polymer-mortar strengthening system is more effective for HSS columns with higher levels of out-of-straightness. Level of residual stress has a slight effect on the gain in the column’s axial strength strengthened with polymer-mortar.

scholarly journals Behavior of bolted lap joints in above ground liquid-filled steel cylindrical tanks

2021 ◽  
Author(s):  
Mehdi Moslemi ◽  
M. Reza Kianoush
Keyword(s):  
Three Dimensional ◽  
Lap Joints ◽  
Fe Analysis ◽  
Main Concern ◽  
Fe Model ◽  
Wide Range ◽  
Cylindrical Tanks ◽  
Bolt Arrangement ◽  
Two Stages ◽  
Good Agreement

Leakage is the main concern in steel bolted liquid tanks. In this study, the performance of this type of construction is investigated using a detailed finite element (FE) analysis. The validity of AWWA design practice in terms of the safe design of this type of structure at a wide range of service loads is evaluated. The FE analysis is performed in two stages using shell and solid elements in a three-dimensional ANSYS environment including the effect of geometric nonlinearity. The proposed FE model is capable to estimate the ultimate behaviors such as capacity curve, yield/failure pattern, and the occurrence of ovalling and curling. The FE results are compared with experimental ones and a good agreement is found. This study shows that the bolt arrangement selected in design can efficiently improve joint performance. It is recommended to use the limited deformation criterion in the leak-resistant design of bolted lap joints.

scholarly journals 3D-Volume Rendering of the Pelvis with Emphasis on Paraurethral Structures Based on MRI Scans and Comparisons between 3D Slicer and OsiriX®

2021 ◽  
Vol 45 (3) ◽  
Author(s):  
C. M. Durnea ◽  
S. Siddiqi ◽  
D. Nazarian ◽  
G. Munneke ◽  
P. M. Sedgwick ◽  
...  
Keyword(s):  
Image Processing ◽  
Secondary Analysis ◽  
Three Dimensional ◽  
3D Models ◽  
Clinical Role ◽  
Cross Sectional ◽  
3D Slicer ◽  
Mri Scans ◽  
3D Volume ◽  
Good Agreement

AbstractThe feasibility of rendering three dimensional (3D) pelvic models of vaginal, urethral and paraurethral lesions from 2D MRI has been demonstrated previously. To quantitatively compare 3D models using two different image processing applications: 3D Slicer and OsiriX. Secondary analysis and processing of five MRI scan based image sets from female patients aged 29–43 years old with vaginal or paraurethral lesions. Cross sectional image sets were used to create 3D models of the pelvic structures with 3D Slicer and OsiriX image processing applications. The linear dimensions of the models created using the two different methods were compared using Bland-Altman plots. The comparisons demonstrated good agreement between measurements from the two applications. The two data sets obtained from different image processing methods demonstrated good agreement. Both 3D Slicer and OsiriX can be used interchangeably and produce almost similar results. The clinical role of this investigation modality remains to be further evaluated.

Finite Element Study of the Cutting Mechanics of the Three Dimensional Rock Turning Process

2015 ◽  
Author(s):  
Demeng Che ◽  
Jacob Smith ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Polycrystalline Diamond ◽  
Close Correlation ◽  
Experimental Results ◽  
Failure Behavior ◽  
Fe Model ◽  
Gas Drilling ◽  
Cutting Mechanics

The unceasing improvements of polycrystalline diamond compact (PDC) cutters have pushed the limits of tool life and cutting efficiency in the oil and gas drilling industry. However, the still limited understanding of the cutting mechanics involved in rock cutting/drilling processes leads to unsatisfactory performance in the drilling of hard/abrasive rock formations. The Finite Element Method (FEM) holds the promise to advance the in-depth understanding of the interactions between rock and cutters. This paper presents a finite element (FE) model of three-dimensional face turning of rock representing one of the most frequent testing methods in the PDC cutter industry. The pressure-dependent Drucker-Prager plastic model with a plastic damage law was utilized to describe the elastic-plastic failure behavior of rock. A newly developed face turning testbed was introduced and utilized to provide experimental results for the calibration and validation of the formulated FE model. Force responses were compared between simulations and experiments. The relationship between process parameters and force responses and the mechanics of the process were discussed and a close correlation between numerical and experimental results was shown.

Modeling Hydroplaning and Effects of Pavement Microtexture

2005 ◽  
Vol 1905 (1) ◽  
pp. 166-176 ◽  
Author(s):  
G. P. Ong ◽  
T. F. Fwa ◽  
J. Guo
Keyword(s):  
Three Dimensional ◽  
Flow Simulation ◽  
Experimental Results ◽  
Tire Pressure ◽  
Finite Volume Model ◽  
Proposed Model ◽  
Loss Of Contact ◽  
The One ◽  
Theoretical Considerations ◽  
Good Agreement

Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of contact between its tires and the pavement surface. This paper presents the development of a three-dimensional finite volume model that simulates the hydroplaning phenomenon. The theoretical considerations of the flow simulation model are described. The simulation results are in good agreement with the experimental results in the literature and with those obtained by the well-known hydroplaning equation of the National Aeronautics and Space Administration (NASA). The tire pressure–hydroplaning speed relationship predicted by the model is found to match well the one obtained with the NASA hydroplaning equation. Analyses of the results of the present study indicate that pavement microtexture in the 0.2- to 0.5-mm range can delay hydroplaning (i.e., raise the speed at which hydroplaning occurs). The paper also shows that the NASA hydroplaning equation provides a conservative estimate of the hydroplaning speed. The analyses in the present study indicate that when the microtexture of the pavement is considered, the hydroplaning speed predicted by the proposed model deviates from the speed predicted by the smooth surface relationship represented by the NASA hydroplaning equation. The discrepancies in hydroplaning speed are about 1% for a 0.1-mm microtexture depth and 22% for a 0.5-mm microtexture depth. The validity of the proposed model was verified by a check of the computed friction coefficient against the experimental results reported in the literature for pavement surfaces with known microtexture depths.

Numerical Calculation of Pressure Fluctuations in the Volute of a Centrifugal Fan

2005 ◽  
Vol 128 (2) ◽  
pp. 359-369 ◽  
Author(s):  
Rafael Ballesteros-Tajadura ◽  
Sandra Velarde-Suárez ◽  
Juan Pablo Hurtado-Cruz ◽  
Carlos Santolaria-Morros
Keyword(s):  
Fluid Dynamics ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Power Spectra ◽  
Operating Conditions ◽  
Experimental Results ◽  
Time Dependent ◽  
Centrifugal Fan ◽  
Wall Pressure Fluctuations ◽  
Good Agreement

In this work, a numerical model has been applied in order to obtain the wall pressure fluctuations at the volute of an industrial centrifugal fan. The numerical results have been compared to experimental results obtained in the same machine. A three-dimensional numerical simulation of the complete unsteady flow on the whole impeller-volute configuration has been carried out using the computational fluid dynamics code FLUENT®. This code has been employed to calculate the time-dependent pressure both in the impeller and in the volute. In this way, the pressure fluctuations in some locations over the volute wall have been obtained. The power spectra of these fluctuations have been obtained, showing an important peak at the blade passing frequency. The amplitude of this peak presents the highest values near the volute tongue, but the spatial pattern over the volute extension is different depending on the operating conditions. A good agreement has been found between the numerical and the experimental results.

A Stochastic Nonlinear Constitutive Law for Concrete

1989 ◽  
Vol 111 (4) ◽  
pp. 443-449 ◽  
Author(s):  
A. Fafitis ◽  
Y. H. Won
Keyword(s):  
Stochastic Model ◽  
Elastic Moduli ◽  
Three Dimensional ◽  
Path Dependency ◽  
Experimental Results ◽  
Constitutive Law ◽  
Induced Anisotropy ◽  
Nonproportional Loading ◽  
Strain Relationship ◽  
Good Agreement

An incremental three-dimensional stress-strain relationship for concrete with induced anisotropy has been developed. The nonlinearity and path-dependency are modeled by expressing the elastic moduli at each increment as function of the octahedral and deviatoric strains, based on a uniaxial stochastic model developed earlier. Predictions of multiaxial response under proportional and nonproportional loading are in good agreement with experimental results.

A Hybrid Model for Predicting Gas Entrainment in a Small Branch From a Co-Current Flowing Gas-Liquid Regime

2010 ◽  
Author(s):  
Robert Bowden ◽  
Wael Saleh ◽  
Ibrahim Hassan
Keyword(s):  
Digital Imaging ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Critical Conditions ◽  
Inertial Effects ◽  
Cross Sectional ◽  
Gas Entrainment ◽  
Small Branch ◽  
Dip Angle ◽  
Good Agreement

An analytical model was developed to predict the critical conditions at the onset of gas entrainment in a single downward oriented branch. The branch was installed on a horizontal square cross-sectional channel having a smooth stratified co-currently flowing gas-liquid regime in the upstream inlet region. The branch flow was simulated as a three-dimensional point-sink while the downstream run flow was treated with a uniform velocity at the critical dip location. A boundary condition was imposed in the model whereby the flow distribution between the branch and run was obtained experimentally and digital imaging was used to quantify the critical dip location through the dip angle. Three constant dip angles were evaluated in the model and results showed the dip height to have good agreement with experiments between angles of 50 and 60 degrees. The predicted upstream height, however, did not match well with the experimentally determined height due to the omission of shear and inertial effects between the upstream location and critical dip.

Residual Stress Prediction for Non-Axisymmetric Vessel Penetration Welds

2008 ◽  
Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Measurement Data ◽  
Fe Model ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Stress Prediction ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.

Prediction Laser Sealed Advanced Ceramic Coatings Dimensions by Using Finite Element Model and Computational Method

2011 ◽  
Vol 264-265 ◽  
pp. 1444-1449
Author(s):  
K.M. Adel ◽  
E.K. Ekhlas ◽  
S.H. Shaker
Keyword(s):  
Heat Affected Zone ◽  
Three Dimensional ◽  
Element Model ◽  
Melting Zone ◽  
Ceramic Coatings ◽  
Experimental Results ◽  
Computational Method ◽  
Zone Model ◽  
Good Prediction ◽  
Good Agreement

A three dimensional FE modeling of the laser surface modification is presented. The design capabilities of the ANSYS (11) software were employed for this purpose. The model calculates the dimensions of melting zone and heat affected zone. Model simulations are compared with experimental results that showed very good agreement. A one dimensional model in V.B language was presented too. The model based on conduction of heat in one dimension neglecting the other losses of heat. The results of VISUAL BASIC were compared with experimental results which showed a very good agreement. The two methods were compared with each other to showing which method have a good prediction compared with experimental results in calculating of fusion zone and heat affected zone "HAZ".

A Method to Estimate Cross-Sectional Stress Distributions on Reinforced Nozzle Corners Under Internal Pressure

2019 ◽  
Author(s):  
Chang-Sik Oh ◽  
Tae-Kwang Song ◽  
Sang-Min Lee
Keyword(s):  
Internal Pressure ◽  
Cross Section ◽  
Pressure Vessels ◽  
Fe Analysis ◽  
Stress Distributions ◽  
Corner Crack ◽  
Cross Sectional ◽  
Simple Method ◽  
Geometric Variables ◽  
Good Agreement

Abstract Stress distribution through the nozzle corner cross-section may be required to calculate stress intensity factor (SIF) for a nozzle corner crack in accordance with ASME Section XI Nonmandatory Appendix G. This paper proposes a simple method to predict nozzle corner cross-section stress distributions on reinforced nozzle corners of pressure vessels under internal pressure. This method includes simplified equations for predicting stresses on the inner surfaces of the nozzle corner region. These equations are expressed in terms of stress concentration factor (SCF) and geometric variables. Approximate SCF solutions for the reinforced nozzle corners are also proposed. Stress distributions using the proposed method are compared with finite element (FE) analysis results of nozzle-vessel intersections of various geometric dimensions, and agreements are quite good within postulated crack depths. Furthermore, SIFs calculated from the estimated stress distributions in accordance with ASME Section XI Nonmandatory Appendix G are compared with those from the FE results, showing good agreement.

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