Print ISSN: 1681-6900

Online ISSN: 2412-0758

### Keywords : finite element method

##### Eccentricity Effect on Radial Forces of Bearingless BLDC Motor: Study and Analysis

Ali A. Yousif; Ahmed M. Mohammed; Mohammed Moanes E. Ali

Engineering and Technology Journal, 2022, Volume 40, Issue 2, Pages 358-368
DOI: 10.30684/etj.v40i2.2218

The bearingless BLDC motor gathers all advantages of the BLDC motor and bearingless machine, and this motor is extensively used in blood and artificial heart pumps. In a bearingless BLDC motor, there are two sets of windings, the main winding, responsible for producing the motor torque, and the suspension winding, which keeps the rotor in the center without any contact with the stator. Generally, the suspension system is responsible for the generation of the suspension forces to cancel the pull-out forces (radial forces), which strongly depends on the accurate evaluation of radial forces distribution at different operating conditions. In this paper, a mathematical model based on the finite element method is used to calculate and analyze the radial force of a bearingless blood pump BLDC motor using Ansys/Maxwell. Based on Maxwell equations, the normal and tangential components of the airgap flux density is determined and used to calculate the radial force, magnitude, and direction. In addition, different cases of rotor displacement under eccentricity conditions are covered. The relation between the rotor displacement and radial force is analyzed, accounting for the displacement direction. Finally, the results are analyzed and discussed.

##### Numerical Analysis of Linear Elevator Structure Using Finite Element Method

Saba A. Othman; Jamal A.-K. Mohammed; Farag M. Mohammed

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1430-1436
DOI: 10.30684/etj.v39i9.2083

In this work, the structure of the linear elevator prototype had been investigated numerically using finite element method. The linear motor structure parameters analyzed using Maxwell ANSYS. The time-stepping method depending on Maxwell equations be applied for analyzing and optimizing the magnetic and force characteristics. While the elevator structure parameters were analyzed using ANSYS workbench based on the principle of virtual work. The frame considered as clamped- clamped beam, and the base of the car considered as thin plate with small deflection. The analysis done with maximum applied load of 360 N at 1.5 safety factor. The results show the distribution of the magnetic lines, the flux density values plus the leakage flux inside the slots. The maximum Von-Mises stress and the deformations of the frame and plate at maximum load are acceptable and present save design. In which the maximum deflection of the thin plate not exceed (thickness/5) at maximum design load.

##### Design and Performance Analysis of Permanent Magnet Synchronous Motor for Electric Vehicles Application

Mustafa Y. Bdewi; Ahmed M. Mohammed; Mohammed M. Ezzaldean

Engineering and Technology Journal, 2021, Volume 39, Issue 3A, Pages 394-406
DOI: 10.30684/etj.v39i3A.1765

In electrical vehicle applications, power density plays a significant role in improving machine performance. The main objective of this paper is to design and analyze the performance of in-wheel outer rotor permanent magnet synchronous motor (PMSM) used in electric vehicles based on a previously designed model. The key challenge is to achieve the best machine performance regarding the highest torque density and lowest torque ripple. This work also aims at reducing the machine cost by using permanent magnet (PM) material, which has less energy density than the PM used in the previously designed model. An optimization procedure is carried out to improve the generated torque, keeping the same aspects of size and volume of the selected machine. On the other hand, the other specifications of the machine are taken into consideration and are maintained within the acceptable level. According to their major impact on the machine’s performance, the most important parameters of machine designing is selected during the optimization procedure. This proposed machine is implemented and tested using the finite element software package “MagNet 7.4.1” with Visual Basic 16.0 programming language and MATLAB 9.5 Simulink for post-processing.

##### Effect of Orientation and Pre-Tension on Stresses Distribution on V-Die Bending Processes by Finite Element Method

Adil S. Jabber; Aseel H. Abed; Anwar H. Zabon

Engineering and Technology Journal, 2020, Volume 38, Issue 5, Pages 636-648
DOI: 10.30684/etj.v38i5A.457

Simulation of metal forming processes using the Finite Element Method (FEM) is a well-established procedure, being nowadays possible to develop alternative approaches, such as inverse methodologies, in solving complex problems. This study investigated the effect of orientation and pre-tension on stresses distribution numerically by software ANSYS 19 using the finite element method. The pre-tension is 55% from total strained in each rolling direction. The results show that the orientation has a significant effect on stresses distribution and stress value before and after pre-tension 55%. Although there is a regular distribution of stresses in three direction, but there is significant difference in the values of stresses in each of (0, 45, 90) degrees. The highest value of t rolling direction. The pre-tension has a greater impact on stresses distribution and stress value. Although, there is a regular distribution of stresses in blank before and after pre-tension, but there is significant difference in the values. Where in 0 degree on rolling direction the stresses increased by 31.7% from their values before pre-tension, while in 45 degrees on rolling direction the stresses increased by 35.6% and in 90 degrees on rolling direction the stresses increased by 23.6% from their values before pre-tension.

##### Experimental and Numerical Study of the Earing Defect During Square Deep Drawing Process

Kariem M. Younis; Adil. Sh. Jaber

Engineering and Technology Journal, 2018, Volume 36, Issue 12A, Pages 1267-1275
DOI: 10.30684/etj.36.12A.8

Deep drawing process is a very complex process which controls a lot of parameters and the associated defects. The aims of this research are to discuss the effect of parameters of the process utilized in square deep drawing process such ; material properties, blank size, blank shape on the height and shape of earing defect appear of the drawn cup. Three dimensions model from low carbon steel (AISI 1008) with thickness 0.7mm of square cup (41.4mm by 41.4mm). The finite element software (ANSYS 11) was utilized to carry out the numerical simulation of the deep drawing process, and the experimental work result of earing was compared with numerical of earing shape result. In this work, three types of the radius of die entry of 3, 5, 7mm, three shapes of the blank (circular, octagonal, and square) with various diameters, four types of radius of the punch profile of 3, 5, 6, and 7mm had been selected to form a cup with square sides. The results show that, The circular blank give the best results according to earing defect and useful height of the drawn cup, when square shape of blanks were utilized, excessive earing will show in the square cup, due to non-uniform distribution of blank material around the perimeter of the die cavity, minimum material in the flat side and too much material found in the die corner, while when using octagonal shape of blanks which have a same surface area to the square blank, the earing will reduce in the corner of the cup due to extract of the too much material from the blank corners. The results showed a high agreement between the experimental work and numerical simulation reached to 85 % in terms of the shapes and lengths of the earing appearing in the square cups.

##### Investigation of The Effect of Loading Paths in the Tube Hydroforming Process

Engineering and Technology Journal, 2018, Volume 36, Issue 12A, Pages 1236-1243
DOI: 10.30684/etj.36.12A.4

The control accurately of internal pressure, axial feeding and paths of loading which have important influences on the final tube quality. In this research an impact of loading path of the tube hydroforming process and final part requirements ( i.e. thickness specification and shape conformation) were studied numerically. Small bulge shape tube hydroforming parts were utilized in the finite element analyses to get several guidelines on the effect of the relation between the internal pressure and axial compressive feeding programs. Two dimension model of bulge shape tube (50 mm) bulge width has been developed from cylindrical tube with thickness (2mm) of the copper and (60 mm) outer diameter. A commercial available finite element program code (ANSYS 11), is used to perform the numerical simulation of the tube hydroforming operation. The results demonstrate that, the loading path has very important influenced on the thickness distribution over the tube and capability attained the target shape of the required product.

##### Modeling of Continues Laser Welding for Ti-6Al-4V Alloys Using COMSOL Multiphysics Software

Haneen A. Salman; Kadhim A. Hubeatir; Mohanned M. AL-Khafaji

Engineering and Technology Journal, 2018, Volume 36, Issue 8A, Pages 914-918
DOI: 10.30684/etj.36.8A.11

A model for laser welding process using finite element method, the model was used for this work using the COMSOL Multiphysics software to predict the distribution of the temperature in the joint and to show the four welding zones (the melting zone, partial melting zone, zone affected by heat, and the material base). CO2 continues (CW) Laser used in the model welding thin sheets of titanium alloy Ti-6Al-4V. The results of this simulation work have been compared with the experimental works to show good agreement.

##### Metal Flow Control in Producing the Non Symmetrical Parts in Deep Drawing Process

Kariem M. Younis; Adil SH. Jaber

Engineering and Technology Journal, 2018, Volume 36, Issue 6A, Pages 603-611
DOI: 10.30684/etj.36.6A.2

the quality of the cups drawn in the deep drawing process are secured by the rate of metal flow into the die cavity, efficiently control on the metal flow can reduce and eliminate a lot of defects such as wrinkling, tearing and earing especially in the square deep drawing due to the non-uniform stresses induced along die cavity. This control is obtained using a restraining force supplied by blank holder tool or draw beads or both. Therefore this research focuses on the study these parameters numerically and experimentally. Ansys software based on finite element method was used to model and analyze the influence of blank holder gap and draw bead parameters in the forming process. Appropriate number of the experiments were done to compare and verify the results obtained in the numerical simulation.

##### Experimental and Numerical Analysis of Piled Raft Foundation Embedded within Partially Saturated Soil

M.R. Mahmood; S.F.A. Al-Wakel; A.A. Hani

Engineering and Technology Journal, 2017, Volume 35, Issue 2A, Pages 97-105
DOI: 10.30684/etj.35.2A.1

This paper presents an experimental and numerical study to investigate the load carrying capacity of piled raft foundation embedded within partially saturated sandy soil. The effect of matric suction on the bearing capacity of the foundation system was investigated. The experimental work consists of two models of foundation, circular raft foundation and circular piled raft foundation. The circular raft foundation has dimensions of 10cm in diameter, and 2.5cm thickness, while the piled raft foundation has the same dimensions of the circular raft model but with a single pile of 2.0cm in diameter and 40.0cm in length fixed at the center of the raft. Both models are loaded and tested under both fully saturated condition and unsaturated conditions, which are achieved by, predetermined lowering of water table. The lowering of water table below the soil surface was achieved in to two different depths to get different values of matric suction and the relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers (IRROMETER). The soil water characteristic curve (SWCC) estimated by applying fitting methods through the software (SoilVision). A validation process then was carried out for the case of circular piled raft foundation with lowering the water table 45cm bellow soil surface in the aid of a sufficient finite element computer program ABAQUS 6.12. An eight-node axisymmetric quadrilateral element CAX8RP and CAX8R were used to simulate the soil continuum and piled raft respectively. The interaction method used to simulate the intersect surfaces of the system (pile-raft-soil) is a surface-to-surface discretization method under the concept of master and slave theory. The behavior of piled raft material is simulated by using a linear elastic model while the behavior of soil is simulated by an elasto-plastic model by the use of the Mohr-Coulomb failure criterion. The results of the experimental work demonstrate that the matric suction has a significant role on the bearing capacity of all tested models. It shows that the ultimate bearing capacity of circular raft foundation under a partially saturated condition is increases by about (7.0-8.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. While the ultimate bearing of circular piled raft foundation under partially saturated condition increases by about (8.0-9.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. The results of the ultimate bearing capacity of piled raft foundation that obtained from the experimental model and from the numerical modelling for the same soil condition and same matric suction indicate that a successful validation is achieved for the simulation process.

##### Thermal Lensing Reduction in Conventional and Composite Nd:YAG Laser Rod

Mohammed Jalal AbdulRazzaq; Abdulla K. Abass; Wail Yas Nassir

Engineering and Technology Journal, 2016, Volume 34, Issue 11, Pages 2031-2035
DOI: 10.30684/etj.34.11A.9

A finite-element method (FEM) wasused to simulate numerically the effect of thermal lensing in YAG rods doped with Nd ion using LASCAD software. The temperature distribution and thermal lensing focal length of the composite laser rod (YAG/Nd:YAG) with one undoped end cap was considered and compared with conventional laser rod (Nd:YAG) by applying software. Results show that thermal lensing effects were reduced by a factor of 2 using (YAG/Nd:YAG) composite rod at pump power of 20W.

##### Numerical Analysis of The Multi-Stage Reverse Deep Drawing Process

Kariem Muhson Younis; Adil Shbeeb Jaber; Ammar Mahdi salah

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 613-622
DOI: 10.30684/etj.34.3A.15

The paper presents an analysis of the multistage deep drawing process considering the three deformation stages namely drawing reverse and reverse redrawingrespectively. This work aim to study the mechanism of deformation during the redrawing process where the second and the third stages were done in reverse redrawing and study the effect of this mechanism on produced cup wall thickness, strain distribution across the wall of the drawn part. 2-D model of cylindrical cup (46.75mm) diameter has been developed in the first stage from sheet with thickness (0.5mm) of the low carbon steel (AISI 1008) and (85mm) diameter, while for second and third stages of drawing a punch diameter (32.725mm, 27.489mm) respectively, and inside diameter of dies equal to (33.825mm, 28.589mm) respectively, the clearance is chosen for three stage equal to 0.55mm. A commercial available finite element program code (ANSYS 11), is used to perform the numerical simulation of the multistage deep drawing. The results show that, when considering multi-stage drawing, the task is even more difficult because the strain and thickness distribution resulting from the first stage will influence the subsequent results,increase in thinning in the wall cup will appear in the second and third stages. Finally this work introduces new method (multi reverse redrawing) to produce circular cup throw three stages of drawing reduction in one stroke without the need to the loading and unloading the tools among the stages as in direct redrawing which means reducing the cost, time, efforts and enhancing cup production.

##### Study of the Influence of the Elastic Rubber Cushion on Product Quality Formed by a Multi - Point Forming (MPF) Process

Marwa Sabah Fakhri; Sadiq Jaffar Aziz

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 452-463
DOI: 10.30684/etj.34.3A.3

The Multi-Point Forming (MPF) is an advanced flexible manufacturing technology for three – dimensional sheet metal forming. This is replacing the conventional solid dies by a set of discrete punches called (punch group).
This work presents the design and manufacturing of (MPF) dies. It covers also, the effect of using an elastic cushion on the quality of products. This technique eliminates the formation of dimples which, otherwise reduces the quality of product. The work falls into two parts. Part one includes the use of ANSYS, which employs a finite element method (FEM) for the simulation of MPF components, namely: upper jaw, lower die and cushion. In the other part (experimental), a complete MPF die was designed and manufactured in the local market.
The copper sheet metal was selected to study the influence of the elastic cushion on the quality of product which formed by MPF process. This rubber was used to avoid the dimples occurring on the metal surface. Experimental and numerical results showedthatthis technique produces a better quality free from dimples. The cushion proved to be effective in elimination of the thickness change. The thickness change was found to be in the range (0-0.05) for a blank of 2 mm.
Hence, it is recommended that the (MPF) method is effective in product quality. However, two layers of cushion are necessary to separate between the workpiece and pins to reduce the work piece deformation. Also, the numerical simulation was used by (ANSYS) software which was compared with the experimental result. A good agreement for numerical and experimental results was found.

##### Effect of Web Opening on the Ultimate Capacity of Steel Plate Girders under Two Points Load

Mazin A. Al-Mazini

Engineering and Technology Journal, 2016, Volume 34, Issue 1, Pages 165-177
DOI: 10.30684/etj.34.1A.14

The structural behavior of steel plate girders with web opening is investigated in this study. An experimental and theoretical investigation of plate girders with circle and square openings in the web was conducted. The experimental work included testing of seven plate girder specimens under two point loads. Three specimens were tested to observe the influence of the circular web opening. The influence of the presence of square web openings was studied by testing other three specimens. The last one was tested without opening as a reference (control) specimen. These specimens had the same dimensions. The experimental results showed that the ultimate load capacity of the girders decreases with increasing the opening size, and the position of plastic hinge depends on the size of hole.
Three-dimensional nonlinear finite element analysis has been used to conduct the numerical investigation of the structural behavior of plate girders with web opening. ANSYS (version 12.0) computer program was used in this study. Four- nodes shell element (SHELL 181) was used to represent the steel plate. The proposed finite element model has been used to carry out a parametric study to investigate the effects of two parameters; web slenderness and flange stiffness ratios, on the ultimate load capacity of plate girders with circular web openings.

##### Experimental and Finite Element Analysis on Rounded Corners Square Shape Tube Hydroforming Process

Hani Aziz Ameen; Nahedh Mahmood Ali

Engineering and Technology Journal, 2014, Volume 32, Issue 9, Pages 2148-2164
DOI: 10.30684/etj.32.9A4

Tube hydroforming is a forming process where an inner pressure combined with axial feeding deforms the tube to the shape of a die cavity, i.e. the process state where the hardening of the material is unable to resist the increase in inner pressure and wall thickness reduction. In the current work the tube with circular cross section is deformed to square cross section using hydraulic pressure. The die of the square edges is designed and manufacturing to change the tube with circular cross section to square cross section. The die and tools were designed and manufactured in order to satisfy the experimental work.The hydraulic system manufactured is capable to give several values of internal pressure. Initially circular tubes are inflated against a square die while simultaneously they are axially compressed in order to delay wall thinning and burst and achieve an accept tube wall thickness distribution. The dimension of tube used in the experimental work of copper is (L=110 mm, do=9.4 mm , to=1.5mm) to obtain forming limit diagram and mechanical properties of tube and value of the bursting pressure and final thickness for copper tube (170MPa ) and 1.18 mm. A squared grid has been printed by screen method with dimensions (5x5mm) the strain measurement accomplished by measuring the dimensions of the grid printed before and after deformation. The finite element method was applied via ANSYS11software package in order to determine the tube thickness, stress and strain behavior and the internal pressure required to form the square shape tube and the radius of curvature of the tube.It was found that the generated strain during the tube hydroforming process in the square cross – sectional die was less than that in ANSYS software within 20%. The results showed good agreement.

##### Influence of the Butt Joint Design of TIG Welding on the Thermal Stresses

Hani Aziz Ameen; Khairia Salman Hassan; Muwafaq Mehdi Salah

Engineering and Technology Journal, 2011, Volume 29, Issue 14, Pages 2841-2858

The aim of this paper is to demonstrate the influence of the single butt joint design of TIG welding on the thermal stresses for carbon steel type St-37. The butt welding was performed by V angles 30°,45°,60° and 90° and the thermal stresses analysis is based on the local moving heat flux. The numerical model developed by ANSYS12
software based on solving the three dimensional energy equation, considering moving heat source and temperature dependent material properties. Temperature and stresses distributions were obtained function of time. From the results, it is evident that the
joint design has an important role in the welding process, when the edge angle of the welding region gets bigger, the faults get less due to increase of heat flux in the welding region. It can be concluded that the specimen with less than 6mm thickness can be welded without edge angle preparation, due to increase the thermal stresses
when edge angle is evident and higher thermal stresses distribution was at edge angle 60° and lowest thermal stresses distribution was at 90°.

##### Influence of Metal Type on the Deep Drawing Force by Experimental and Finite Element Method

Moneer H. Al-Saadi; Hani Aziz Ameen; Rawa Hamed M. Al-Kalali

Engineering and Technology Journal, 2011, Volume 29, Issue 13, Pages 2601-2608

This paper is aimed to study the effect of material type on the drawing force. Three metals are used (low carbon steel 1008 AISI, Austenitic stainless steel 304 AISI, and pure aluminum 1100), as a sheet with thickness of 0.5mm for each one, and they were cutting as a blank with 80 mm diameter, then drawn in a die with 44mm diameter to produce cup. To predict the deep drawing force by finite element method, Hill's yield criteria is used, which examines the effect of anisotropy. Two dimension axisymmetry model of deep drawing were built and analyzed by ANSYS FEM code. The results show that the drawing force for stainless steel is higher than the other two metals due to the difference in metallurgical structure. The numerical results were compared with the experimental; good agreement was found between finite element and experimental results.

##### Numerical and Experimental Investigation of Mechanical and Thermal Buckling Loads of Composite Laminated Plates

Ammar A. Hussein; Hassan H. Mahdi; Nessren H. Ahmed

Engineering and Technology Journal, 2011, Volume 29, Issue 9, Pages 1830-1844

In this study, the effect of temperature, aspect ratio, number of layer and
boundary conditions on critical buckling load of composite laminated plate is
investigated experimentally and numerically. Simply-Simply-Free-Free and
Clamp-Clamp-Free-Free boundary conditions, three temperatures (40°C, 60°C and
80°C) and four aspect ratio (1, 1.3, 1.5 and 2) will consider for the experimental
work. The thickness of the plate was changed by increasing the number of layer.
It can be seen that when the temperature changes from 40°C to 80°C the
maximum value of Pcr is about (225 N/mm) at (T = 40°C, a/b = 2 and NL = 4), the
minimum value of Pcr is about (11.70 N/mm) at (T = 80°C, a/b = 1 and NL = 2).
Also, it can be shown that in the case of symmetric cross ply laminate (0o/90o/0o)
about 50 % at aspect ratio equal to 1. Finally, It is shown that the critical buckling
load increases with increasing the aspect ratio at constant temperature, number of
layers and boundary conditions.

##### Active Magnetic Bearing Design Optimization and Transient-State Analysis Using ANSYS

Adil H. Ahmed; Thamir M. Abdul Wahab

Engineering and Technology Journal, 2010, Volume 28, Issue 16, Pages 5171-5187

This paper presents design optimization, and transient-state analysis of
active magnetic bearings (AMB) using the powerful ANSYS software package.
ANSYS software provides the required environment for numerical modeling and
analysis based on the finite element method (FEM). In this paper two programs
are developed in ANSYS, the first for modeling and optimizing the analytically
designed active magnetic bearing, and the second for transient-state analysis of the
FE model to investigate the effects of eddy currents on the considered active
magnetic bearing.

##### Nonlinear Finite Element Analysis of Reinforced Concrete Beams with a Small Amount of Web Reinforcement under Shear

Thaer Jasim Mohammed

Engineering and Technology Journal, 2009, Volume 27, Issue 8, Pages 1485-1496

This research work presents a nonlinear finite element investigation on the
behavior of reinforced concrete beams with a small amount of web reinforcement under
shear. This investigation is carried out in order to get a better understanding of their
The three- dimensional 20-node brick elements are used to model the concrete, while
the reinforcing bars are modeled as axial members embedded within the concrete brick
elements. The compressive behavior of concrete is simulated by an elastic-plastic
work-hardening model followed by a perfectly plastic response, which terminated at
the onset of crushing. In tension, a fixed smeared crack model has been used.