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".

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.

scholarly journals An efficient three-dimensional foil structure model for bump-type gas foil bearings considering friction

Friction ◽  
2020 ◽  
Author(s):  
Yongpeng Gu ◽  
Xudong Lan ◽  
Gexue Ren ◽  
Ming Zhou
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Element Model ◽  
Experimental Results ◽  
Synthesis Methods ◽  
Structure Model ◽  
Foil Bearings ◽  
Static Responses ◽  
Bearing Sleeve ◽  
Shell Finite Element

Abstract This paper presents an efficient three-dimensional (3D) structural model for bump-type gas foil bearings (GFBs) developed by considering friction. The foil structures are modeled with a 3D shell finite element model. Using the bump foil mechanical characteristics, the Guyan reduction and component mode synthesis methods are adopted to improve computational efficiency while guaranteeing accurate static responses. A contact model that includes friction and separation behaviors is presented to model the interactions of the bump foil with the top foil and bearing sleeve. The proposed structural model was validated with published analytical and experimental results. The coupled elastohydrodynamics model of GFBs was established by integration of the proposed structural model with data on hydrodynamic films, and it was validated by comparisons with existing experimental results. The performance of a bearing with an angular misalignment was studied numerically, revealing that the reaction torques of the misaligned bearing predicted by GFB models with 2D and 3D foil structure models are quite different. The 3D foil structure model should be used to study GFB misalignment.

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.

Examination of the Transferability of CTOA From Small-Scale DWTT to Full-Scale Pipe Geometries Using a Cohesive Zone Model

2020 ◽  
Author(s):  
Chris Bassindale ◽  
Xin Wang ◽  
William R. Tyson ◽  
Su Xu
Keyword(s):  
Finite Element ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Element Model ◽  
Full Scale ◽  
Opening Angle ◽  
Small Scale ◽  
Zone Model ◽  
Pipe Model ◽  
Good Agreement

Abstract In this work, the cohesive zone model (CZM) was used to examine the transferability of the crack tip opening angle (CTOA) from small-scale to full-scale geometries. The pipe steel STPG370 was modeled. A drop-weight tear test (DWTT) model and pipe model were studied using the finite element code ABAQUS 2017x. The cohesive zone model was used to simulate crack propagation in 3D. The CZM parameters were calibrated based on matching the surface CTOA measured from a DWTT finite element model to the surface CTOA measured from the experimental DWTT specimen. The mid-thickness CTOA of the DWTT model was in good agreement with the experimental value determined from E3039 and the University of Tokyo group’s load-displacement data. The CZM parameters were then applied to the pipe model. The internal pressure distribution and decay during the pipe fracture process was modeled using the experimental data and implemented through a user-subroutine (VDLOAD). The mid-thickness CTOA from the DWTT model was similar to the mid-thickness CTOA from the pipe model. The average surface CTOA of the pipe model was in good agreement with the average experimental value. The results give confidence in the transferability of the CTOA between small-scale specimens and full-scale pipe.

Residual Stress Modeling of Powder Injection Laser Surface Cladding for Die Repair Applications

2014 ◽  
Author(s):  
Santanu Paul ◽  
Kaunain Ashraf ◽  
Ramesh Singh
Keyword(s):  
Residual Stresses ◽  
Heat Affected Zone ◽  
Three Dimensional ◽  
Base Material ◽  
Element Model ◽  
Repair Process ◽  
Powder Injection ◽  
Injection Technique ◽  
Crucible Steel ◽  
Three Dimensional Finite Element

Laser cladding is a technique in which a layer of material is deposited over a base material in order to improve its wear/corrosion resistance. It is also used as an additive manufacturing and repair technique. In the present work crucible steel CPM9V is deposited over H13 tool steel which could potentially be used for die repair purposes. CO2 laser is used to melt the powder which is deposited by powder injection technique. Note that the dies are exposed to cyclic thermo-mechanical loading and prone to fatigue. Consequently, major issues which needed to be analysed are residual stresses and the heat affected zone. The residual stresses are produced due to high thermal gradients and difference in values of coefficient of thermal expansions of clad and substrate. A three dimensional finite element model is developed to evaluate residual stresses incorporating conductive, convective and radiative heat transfer and assuming temperature dependent thermo-mechanical behaviour for both materials. Experimental analysis is performed using X-ray diffraction technique to evaluate residual stresses and the heat affected zone (HAZ) is characterized via optical microscopy. A comparison between the model predictions and the experimental results shows that model is able to capture the phenomena during the repair process.

Comparison and Validation of Dynamics Simulation Models for a Structurally Flexible Manipulator

1998 ◽  
Vol 120 (3) ◽  
pp. 404-409 ◽  
Author(s):  
Jeff Stanway ◽  
Inna Sharf ◽  
Chris Damaren
Keyword(s):  
Simulation Models ◽  
Element Model ◽  
Experimental Results ◽  
Dynamics Simulation ◽  
Flexible Manipulator ◽  
Direct Drive ◽  
Inertial Nonlinearities ◽  
Dynamics Models ◽  
The Finite Element Model ◽  
Good Agreement

This paper presents a series of experimental results obtained with a 2-DOF flexible-link direct-drive manipulator. First, we conduct a frequency analysis by comparing experimental natural frequencies with those predicted by the finite element model. Then, the time responses from four dynamics models are compared with each other and with the experiment. It is demonstrated that higher order nonlinearities are less important for slow maneuvers by close agreement between all four simulation models. For fast maneuvers, the two simpler models fail to predict a physically meaningful response. Good agreement with experimental results is attained with a model which accounts for all inertial nonlinearities. It is also shown that inclusion of damping in the dynamics models has a significant impact on their performance, as well as improving the correlation with experimental data.

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.

Finite Element Model of a Heated Wire Catalyst in Cross Flow

2008 ◽  
Author(s):  
Katie Leichliter ◽  
Bob Lounsbury ◽  
Judi Steciak ◽  
Ralph Budwig ◽  
Steve Beyerlein
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Cross Flow ◽  
Element Model ◽  
Trailing Edges ◽  
Dimensional Finite Element ◽  
Fuel Mixtures ◽  
Three Dimensional Finite Element ◽  
Calculated Average ◽  
Good Agreement

Experimentally obtained temperatures of a heated coiled platinum wire in low Reynolds Number cross-flow were compared with a three-dimensional finite element (finite volume) model. The calculated average wire temperature was in good agreement with experimentally obtained values with deviations close to experimental uncertainty bounds at temperatures between 530K and 815K. The model predicted a temperature variation along each coil, with the lowest temperatures along the leading edges of the coil and the higher temperatures at the trailing edges. The rate of heat generated at the wire surface from catalytic reactions was found for the ignition of lean propane/oxygen/nitrogen mixtures. We studied the coiled catalytic wire as part of our efforts to ignite very lean homogeneous air-fuel mixtures in transportation engines under conditions approaching Homogeneous Charge Compression Ignition (HCCI).

scholarly journals Springback Calibration of a U-Shaped Electromagnetic Impulse Forming Process

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 603 ◽  
Author(s):  
Xiaohui Cui ◽  
Zhiwu Zhang ◽  
Hailiang Yu ◽  
Xiaoting Xiao ◽  
Yongqi Cheng
Keyword(s):  
Tangential Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Simulation Method ◽  
Discharge Voltage ◽  
Electromagnetic Forming ◽  
Forming Process ◽  
Sheet Bending ◽  
Sequential Coupling ◽  
Good Agreement

A three-dimensional (3D) finite-element model (FEM), including quasi-static stamping, sequential coupling for electromagnetic forming (EMF) and springback, was established to analyze the springback calibration by electromagnetic force. Results show that the tangential stress at the sheet bending region is reduced, and even the direction of tangential stress at the bending region is changed after EMF. The springback can be significantly reduced with a higher discharge voltage. The simulation results are in good agreement with the experiment results, and the simulation method has a high accuracy in predicting the springback of quasi-static stamping and electromagnetic forming.

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