**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**1336

# Search results for: wall friction angle.

##### 1336 Influence of the Moisture Content on the Flowability of Fine-Grained Iron Ore Concentrate

**Authors:**
C. Lanzerstorfer,
M. Hinterberger

**Abstract:**

The iron content of the ore used is crucial for the productivity and coke consumption rate in blast furnace pig iron production. Therefore, most iron ore deposits are processed in beneficiation plants to increase the iron content and remove impurities. In several comminution stages, the particle size of the ore is reduced to ensure that the iron oxides are physically liberated from the gangue. Subsequently, physical separation processes are applied to concentrate the iron ore. The fine-grained ore concentrates produced need to be transported, stored, and processed. For smooth operation of these processes, the flow properties of the material are crucial. The flowability of powders depends on several properties of the material: grain size, grain size distribution, grain shape, and moisture content of the material. The flowability of powders can be measured using ring shear testers. In this study, the influence of the moisture content on the flowability for the Krivoy Rog magnetite iron ore concentrate was investigated. Dry iron ore concentrate was mixed with varying amounts of water to produce samples with a moisture content in the range of 0.2 to 12.2%. The flowability of the samples was investigated using a Schulze ring shear tester. At all measured values of the normal stress (1.0 kPa – 20 kPa), the flowability decreased significantly from dry ore to a moisture content of approximately 3-5%. At higher moisture contents, the flowability was nearly constant, while at the maximum moisture content the flowability improved for high values of the normal stress only. The results also showed an improving flowability with increasing consolidation stress for all moisture content levels investigated. The wall friction angle of the dust with carbon steel (S235JR), and an ultra-high molecule low-pressure polyethylene (Robalon) was also investigated. The wall friction angle increased significantly from dry ore to a moisture content of approximately 3%. For higher moisture content levels, the wall friction angles were nearly constant. Generally, the wall friction angle was approximately 4° lower at the higher wall normal stress.

**Keywords:**
Iron ore concentrate,
flowability,
moisture content,
wall friction angle.

##### 1335 Friction Estimation and Compensation for Steering Angle Control for Highly Automated Driving

**Authors:**
Marcus Walter,
Norbert Nitzsche,
Dirk Odenthal,
Steffen M¨uller

**Abstract:**

**Keywords:**
Friction estimation,
friction compensation,
steering
system,
lateral vehicle guidance.

##### 1334 A Comparison of Single Point Incremental Forming Formability between Carbon Steel and Stainless Steel

**Authors:**
K. Rattanachan

**Abstract:**

In sheet metal forming process, raw material mechanical properties are important parameters. This paper is to compare the wall’s incline angle or formability of SS 400 steel and SUS 304 stainless steel in single point incremental forming. The two materials are ferrous base alloyed, which have the different unit cell, mechanical property and chemical composition. They were forming into cone shape specimens having 100 mm diameter with different wall’s incline angle: 90o, 75o and 60o. The investigation was continued until the specimens formed surface facture. The experimental result showed that the smaller the wall incline angle higher the formability with the both materials. The formability limit of the ferrous base alloy was approx. 60o wall’s incline angle. By nature, SS 400 has higher formability than SUS 304. This result can be used as the initial data in designing the single point incremental forming parts.

**Keywords:**
NC incremental forming,
Single point incremental
forming,
Wall incline angle,
Formability.

##### 1333 A Wall Law for Two-Phase Turbulent Boundary Layers

**Authors:**
Dhahri Maher,
Aouinet Hana

**Abstract:**

**Keywords:**
Bubbly flows,
log law,
boundary layer.

##### 1332 The Determination of Cellulose Spiral Angle by Small-Angle X-Ray Scattering from Structurally Characterized Acacia mangium Cell Wall

**Authors:**
Tamer A. Tabet,
Fauziah Abdul Aziz,
Shahidan Radiman

**Abstract:**

**Keywords:**
Small-Angle X-Ray Scattering,
Microfibril Angle,
MFA,
rectangular cell wall and real cell wall,
Acacia mangium.

##### 1331 Numerical Modeling of Direct Shear Tests on Sandy Clay

**Authors:**
R. Ziaie Moayed ,
S. Tamassoki ,
E. Izadi

**Abstract:**

**Keywords:**
Shear strength,
Finite element analysis,
Large direct
shear test,
Sandy clay.

##### 1330 Numerical Analysis of Flow through Abrasive Water Suspension Jet: The Effect of Garnet, Aluminum Oxide and Silicon Carbide Abrasive on Skin Friction Coefficient Due To Wall Shear and Jet Exit Kinetic Energy

**Authors:**
Deepak D,
Anjaiah D,
Yagnesh Sharma N.

**Abstract:**

**Keywords:**
Abrasive water suspension jet,
Skin friction
coefficient,
Jet kinetic energy,
Particulate loading,
Stokes number.

##### 1329 Effect of Silt Presence on Shear Strength Parameters of Unsaturated Sandy Soils

**Authors:**
R. Ziaie Moayed,
E. Khavaninzadeh,
M. Ghorbani Tochaee

**Abstract:**

Direct shear test is widely used in soil mechanics experiment to determine the shear strength parameters of granular soils. For analysis of soil stability problems such as bearing capacity, slope stability and lateral pressure on soil retaining structures, the shear strength parameters must be known well. In the present study, shear strength parameters are determined in silty-sand mixtures. Direct shear tests are performed on 161 Firoozkooh sand with different silt content at a relative density of 70% in three vertical stress of 100, 150, and 200 kPa. Wet tamping method is used for soil sample preparation, and the results include diagrams of shear stress versus shear deformation and sample height changes against shear deformation. Accordingly, in different silt percent, the shear strength parameters of the soil such as internal friction angle and dilation angle are calculated and compared. According to the results, when the sample contains up to 10% silt, peak shear strength and internal friction angle have an upward trend. However, if the sample contains 10% to 50% of silt a downward trend is seen in peak shear strength and internal friction angle.

**Keywords:**
Shear strength parameters,
direct shear test,
silty sand,
shear stress,
shear deformation.

##### 1328 Effect of Adverse Pressure Gradient on a Fluctuating Velocity over the Co-Flow Jet Airfoil

**Authors:**
Morteza Mirhosseini,
Amir B. Khoshnevis

**Abstract:**

^{o}and this has due to the jet energized, while the angle of attack 20

^{o}has different. The airfoil cord based Reynolds number has 10

^{5}.

**Keywords:**
Adverse pressure gradient,
fluctuating velocity,
wall jet,
co-flow jet airfoil.

##### 1327 Study of Mechanical Properties of Aluminium Alloys on Normal Friction Stir Welding and Underwater Friction Stir Welding for Structural Applications

**Authors:**
Lingaraju Dumpala,
Laxmi Mohan Kumar Chintada,
Devadas Deepu,
Pravin Kumar Yadav

**Abstract:**

Friction stir welding is the new-fangled and cutting-edge technique in welding applications; it is widely used in the fields of transportation, aerospace, defense, etc. For thriving significant welding joints and properties of friction stir welded components, it is essential to carry out this advanced process in a prescribed systematic procedure. At this moment, Underwater Friction Stir Welding (UFSW) Process is the field of interest to do research work. In the continuous assessment, the study of UFSW process is to comprehend problems occurred in the past and the structure through which the mechanical properties of the welded joints can be value-added and contributes to conclude results an acceptable and resourceful joint. A meticulous criticism is given on how to modify the experimental setup from NFSW to UFSW. It can discern the influence of tool materials, feeds, spindle angle, load, rotational speeds and mechanical properties. By expending the DEFORM-3D simulation software, the achieved outcomes are validated.

**Keywords:**
Underwater friction stir welding,
al alloys,
mechanical properties,
normal friction stir welding.

##### 1326 Study of Natural Convection in a Triangular Cavity Filled with Water: Application of the Lattice Boltzmann Method

**Authors:**
Imen Mejri,
Ahmed Mahmoudi,
Mohamed A. Abbassi,
Ahmed Omri

**Abstract:**

The Lattice Boltzmann Method (LBM) with double populations is applied to solve the steady-state laminar natural convective heat transfer in a triangular cavity filled with water. The bottom wall is heated, the vertical wall is cooled, and the inclined wall is kept adiabatic. The buoyancy effect was modeled by applying the Boussinesq approximation to the momentum equation. The fluid velocity is determined by D2Q9 LBM and the energy equation is discritized by D2Q4 LBM to compute the temperature field. Comparisons with previously published work are performed and found to be in excellent agreement. Numerical results are obtained for a wide range of parameters: the Rayleigh number from to and the inclination angle from 0° to 360°. Flow and thermal fields were exhibited by means of streamlines and isotherms. It is observed that inclination angle can be used as a relevant parameter to control heat transfer in right-angled triangular enclosures.

**Keywords:**
Heat transfer,
inclination angle,
Lattice Boltzmann Method,
Nusselt number,
Natural convection,
Rayleigh number.

##### 1325 Advances on LuGre Friction Model

**Authors:**
Mohammad Fuad Mohammad Naser,
Faycal Ikhouane

**Abstract:**

LuGre friction model is an ordinary differential equation that is widely used in describing the friction phenomenon for mechanical systems. The importance of this model comes from the fact that it captures most of the friction behavior that has been observed including hysteresis. In this paper, we study some aspects related to the hysteresis behavior induced by the LuGre friction model.

**Keywords:**
Hysteresis,
LuGre model,
operator,
(strong) consistency.

##### 1324 Wall Heat Flux Mapping in Liquid Rocket Combustion Chamber with Different Jet Impingement Angles

**Authors:**
O. S. Pradeep,
S. Vigneshwaran,
K. Praveen Kumar,
K. Jeyendran,
V. R. Sanal Kumar

**Abstract:**

^{o}, 30

^{o}, 45

^{o}, and 60

^{o}. We concluded that the jets intersection angle is having a bearing on the time and location of the maximum wall-heat flux zone of the liquid rocket combustion chamber during the start-up transient. We also concluded that the wall heat flux mapping in liquid rocket combustion chamber during the start-up transient is a meaningful objective for the chamber wall material selection and the lucrative design optimization of the combustion chamber for improving the payload capability of the rocket.

**Keywords:**
Combustion chamber,
injector,
liquid rocket,
rocket engine wall heat flux.

##### 1323 Variability of Soil Strength Parameters and its Effect on the Slope Stability of the Želazny Most Tailing Dam

**Authors:**
Stella A. Arnaouti,
Demos C. Angelides,
Theodoros N. Chatzigogos,
Witold M. Pytel

**Abstract:**

**Keywords:**
Soil strength variability,
friction angle spatial
variability,
Želazny Most tailing dam.

##### 1322 A Review on Bearing Capacity Factor Nγ of Shallow Foundations with Different Shapes

**Authors:**
S. Taghvamanesh,
R. Ziaie Moayed

**Abstract:**

There are several methods for calculating the bearing capacity factors of foundations and retaining walls. In this paper, the bearing capacity factor Nγ (shape factor) for different types of foundation have been investigated. The formula for bearing capacity on c–φ–γ soil can still be expressed by Terzaghi’s equation except that the bearing capacity factor Nγ depends on the surcharge ratio, and friction angle φ. It is apparent that the value of Nγ increases irregularly with the friction angle of the subsoil, which leads to an excessive increment in Nγ of foundations with larger width. Also, the bearing capacity factor Nγ will significantly decrease with an increase in foundation`s width. It also should be highlighted that the effect of shape and dimension will be less noticeable with a decrease in the relative density of the soil. Hence, the bearing capacity factor Nγ relatively depends on foundation`s width, surcharge and roughness ratio. This paper presents the results of various studies conducted on the bearing capacity factor Nγ of: different types of shallow foundation and foundations with irregular geometry (ring footing, triangular footing, shell foundations and etc.) Further studies on the effect of bearing capacity factor Nγ on mat foundations and the characteristics of this factor with or without consideration for the presence of friction between soil and foundation are recommended.

**Keywords:**
Bearing capacity,
Bearing capacity factor,
irregular foundation,
shallow foundation.

##### 1321 Effect of Friction Models on Stress Distribution of Sheet Materials during V-Bending Process

**Authors:**
Maziar Ramezani,
Zaidi Mohd Ripin

**Abstract:**

**Keywords:**
Friction model,
Stress distribution,
V-bending.

##### 1320 Friction Calculation and Simulation of Column Electric Power Steering System

**Authors:**
Seyed Hamid Mirmohammad Sadeghi,
Raffaella Sesana,
Daniela Maffiodo

**Abstract:**

**Keywords:**
Friction,
worm gear,
column electric power steering system,
Simulink,
bearing,
electric power steering,
EPS.

##### 1319 Convective Heat Transfer of Internal Electronic Components in a Headlight Geometry

**Authors:**
Jan Langebach,
Peter Fischer,
Christian Karcher

**Abstract:**

**Keywords:**
Enclosure,
heat source,
heat transfer,
mixed
convection.

##### 1318 Static/kinetic Friction Behaviour of a Clutch Facing Material: Effects of Temperature and Pressure

**Authors:**
A. Chaikittiratana,
S. Koetniyom,
S. Lakkam

**Abstract:**

The feasibility of applying a simple and cost effective sliding friction testing apparatus to study the friction behaviour of a clutch facing material, effected by the variation of temperature and contact pressure, was investigated. It was found that the method used in this work was able to give a convenient and cost effective measurement of friction coefficients and their transitions of a clutch facing material. The obtained results will be useful for the development process of new facing materials.

**Keywords:**
Static/kinetic friction,
sliding friction testing apparatus,
contact pressure and temperature dependent of friction coefficients.

##### 1317 Spectral Investigation for Boundary Layer Flow over a Permeable Wall in the Presence of Transverse Magnetic Field

**Authors:**
Saeed Sarabadan,
Mehran Nikarya,
Kouroah Parand

**Abstract:**

**Keywords:**
MHD Falkner-Skan,
nonlinear ODE,
spectral
collocation method,
Bessel functions,
skin friction,
velocity.

##### 1316 Dynamic Active Earth Pressure on Flexible Cantilever Retaining Wall

**Authors:**
Snehal R. Pathak,
Sachin S. Munnoli

**Abstract:**

**Keywords:**
Earth pressure,
earthquake,
2-DOF model,
plaxis,
wall movement,
retaining walls.

##### 1315 Simulation of Kinetic Friction in L-Bending of Sheet Metals

**Authors:**
Maziar Ramezani,
Thomas Neitzert,
Timotius Pasang

**Abstract:**

This paper aims at experimental and numerical investigation of springback behavior of sheet metals during L-bending process with emphasis on Stribeck-type friction modeling. The coefficient of friction in Stribeck curve depends on sliding velocity and contact pressure. The springback behavior of mild steel and aluminum alloy 6022-T4 sheets was studied experimentally and using numerical simulations with ABAQUS software with two types of friction model: Coulomb friction and Stribeck friction. The influence of forming speed on springback behavior was studied experimentally and numerically. The results showed that Stribeck-type friction model has better results in predicting springback in sheet metal forming. The FE prediction error for mild steel and 6022-T4 AA is 23.8%, 25.5% respectively, using Coulomb friction model and 11%, 13% respectively, using Stribeck friction model. These results show that Stribeck model is suitable for simulation of sheet metal forming especially at higher forming speed.

**Keywords:**
Friction,
L-bending,
Springback,
Stribeck curves.

##### 1314 A Simple Device for in-situ Direct Shear and Sinkage Tests

**Authors:**
A. Jerves,
H. Ling,
J. Gabaldon,
M. Usoltceva,
C. Coust´e,
A. Agarwal,
R. Hurley,
J. Andrade

**Abstract:**

This work introduces a simple device designed to perform in-situ direct shear and sinkage tests on granular materials as sand, clays, or regolith. It consists of a box nested within a larger box. Both have open bottoms, allowing them to be lowered into the material. Afterwards, two rotating plates on opposite sides of the outer box will rotate outwards in order to clear regolith on either side, providing room for the inner box to move relative to the plates and perform a shear test without the resistance of the surrounding soil. From this test, Coulomb parameters, including cohesion and internal friction angle, as well as, Bekker parameters can be inferred. This device has been designed for a laboratory setting, but with few modifications, could be put on the underside of a rover for use in a remote location. The goal behind this work is to ultimately create a compact, but accurate measuring tool to put onto a rover or any kind of exploratory vehicle to test for regolith properties of celestial bodies.

**Keywords:**
Simple shear,
friction angle,
Bekker parameters,
device,
regolith.

##### 1313 Analytical Slope Stability Analysis Based on the Statistical Characterization of Soil Shear Strength

**Authors:**
Bernardo C. P. Albuquerque,
Darym J. F. Campos

**Abstract:**

**Keywords:**
Statistical slope stability analysis,
Skew distributions,
Probability of failure,
Functions of random variables.

##### 1312 Advanced Model for Calculation of the Neutral Axis Shifting and the Wall Thickness Distribution in Rotary Draw Bending Processes

**Abstract:**

Rotary draw bending is a method which is being used in tube forming. In the tube bending process, the neutral axis moves towards the inner arc and the wall thickness distribution changes for tube’s cross section. Thinning takes place in the outer arc of the tube (extrados) due to the stretching of the material, whereas thickening occurs in the inner arc of the tube (intrados) due to the comparison of the material. The calculations of the wall thickness distribution, neutral axis shifting, and strain distribution have not been accurate enough, so far. The previous model (the geometrical model) describes the neutral axis shifting and wall thickness distribution. The geometrical of the tube, bending radius and bending angle are considered in the geometrical model, while the influence of the material properties of the tube forming are ignored. The advanced model is a modification of the previous model using material properties that depends on the correction factor. The correction factor is a purely empirically determined factor. The advanced model was compared with the Finite element simulation (FE simulation) using a different bending factor (Bf =bending radius/ diameter of the tube), wall thickness (Wf = diameter of the tube/ wall thickness), and material properties (strain hardening exponent). Finite element model of rotary draw bending has been performed in PAM-TUBE program (version: 2012). Results from the advanced model resemble the FE simulation and the experimental test.

**Keywords:**
Rotary draw bending,
material properties,
neutral
axis shifting,
wall thickness distribution.

##### 1311 Developing a Simple and an Accurate Formula for the Conduction Angle of a Single Phase Rectifier with RL Load

**Authors:**
S. Ali Al-Mawsawi,
Fadhel A. Albasri

**Abstract:**

**Keywords:**
Conduction Angle,
Firing Angle,
Excitation Angle,
Load Angle.

##### 1310 Numerical Study of Laminar Mixed Convection Heat Transfer of a Nanofluid in a Concentric Annular Tube Using Two-Phase Mixture Model

**Authors:**
Roghayyeh Motallebzadeh,
Shahin Hajizadeh,
Mohammad Reza Ghasemi

**Abstract:**

Laminar mixed Convection heat transfer of a nanofluid with prescribed constant heat flux on the inner wall of horizontal annular tube has been studied numerically based on two-phase mixture model in different Rayleigh Numbers and Azimuth angles. Effects of applying of different volume fractions of Al_{2}O_{3} nanoparticles in water as a base fluid on hydrodynamic and thermal behaviors of the fluid flow such as axial velocity, secondary flow, temperature, heat transfer coefficient and friction coefficient at the inner and outer wall region, has been investigated. Conservation equations in elliptical form has been utilized and solved in three dimensions for a steady flow. It is observed that, there is a good agreement between results in this work and previously published experimental and numerical works on mixed convection in horizontal annulus. These particles cause to increase convection heat transfer coefficient of the fluid, meanwhile there is no considerable effect on friction coefficient.

**Keywords:**
Buoyancy force,
Laminar mixed convection,
Mixture model,
Nanofluid,
Two-phase.

##### 1309 Feasibility Study of Friction Stir Welding Application for Kevlar Material

**Authors:**
Ahmet Taşan,
Süha Tirkeş,
Yavuz Öztürk,
Zafer Bingül

**Abstract:**

Friction stir welding (FSW) is a joining process in the solid state, which eliminates problems associated with the material melting and solidification, such as cracks, residual stresses and distortions generated during conventional welding. Among the most important advantages of FSW are; easy automation, less distortion, lower residual stress and good mechanical properties in the joining region. FSW is a recent approach to metal joining and although originally intended for aluminum alloys, it is investigated in a variety of metallic materials. The basic concept of FSW is a rotating tool, made of non-consumable material, specially designed with a geometry consisting of a pin and a recess (shoulder). This tool is inserted as spinning on its axis at the adjoining edges of two sheets or plates to be joined and then it travels along the joining path line. The tool rotation axis defines an angle of inclination with which the components to be welded. This angle is used for receiving the material to be processed at the tool base and to promote the gradual forge effect imposed by the shoulder during the passage of the tool. This prevents the material plastic flow at the tool lateral, ensuring weld closure on the back of the pin. In this study, two 4 mm Kevlar^{®} plates which were produced with the Kevlar^{®} fabrics, are analyzed with COMSOL Multiphysics in order to investigate the weldability via FSW. Thereafter, some experimental investigation is done with an appropriate workbench in order to compare them with the analysis results.

**Keywords:**
Analytical modeling,
composite materials welding,
friction stir welding,
heat generation.

##### 1308 The Study of Super Hydrophobic Surfaces Using High Speed Shadowgraphy

**Authors:**
D. Jasikova,
M. Kotek,
V. Kopecky

**Abstract:**

The aim of this article is the measurement of the basic characteristic of superhydrophobic surfaces using high speed shadowgraphy. Here we describe the novel patented system for the industrial production of superhydrophobic surfaces. These surfaces were investigated with two optically based measurement methods: impinging drop and inclined wall. The results of the visualization and analysis help to state the suitable sample with superhydrophobic properties for mathematic simulation.

**Keywords:**
Antipearl effect,
contact angle,
hydrophobic,
impinging drop,
inclined wall,
measurement,
plasma,
shadowgraphy,
superhydrophobic surface.

##### 1307 Numerical Investigation of Flow Past Cylinderin Cross Flow

**Authors:**
M. H. Alhajeri,
Jasem Alrajhi,
Mohsen Alardhi,
Saleh Alhajeri

**Abstract:**

A numerical prediction of flow in a tube bank is reported. The flow regimes considered cover a wide range of Reynolds numbers, which range from 380 to 99000 and which are equivalent to a range of inlet velocities from very low (0.072 m/s) to very high (60 m/s). In this study, calculations were made using the standard k-e model with standard wall function. The drag coefficient, skin friction drag, pressure drag, and pressure distribution around a tube were investigated. As the velocity increased, the drag coefficient decreased until the velocity exceeded 45 m/s, after which it increased. Furthermore, the pressure drag and skin friction drag depend on the velocity.

**Keywords:**
Numerical,
Fluid,
Flow,
Turbine,
Cooling,
Blade.