Table of content

Iraqi journal of mechanical and material engineering

المجلة العراقية للهندسة الميكانيكية وهندسة المواد

ISSN: 20761819
Publisher: Babylon University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

Iraqi journal for mechanical and material engineering is a refereed scientific journal published quarterly by the engineering college/ university of Babylon. It deals with high quality researches in fields of mechanical and material engineering.

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Contact info

Journal E-mail:
j.mec_mat_eng@yahoo.com
Babylon university/Babylon/Iraq P.O.Box(4)
Tel:++96430245387.(1155)

Table of content: 2017 volume:17 issue:2

Article
DESIGN AND IMPLEMENTATION SINGLE AXIS TRACKER MODEL BASED ON MICROCONTROLLER FOR SOLAR COLLECTOR
تصميم وتنفيذ نموذج تعقب احادي المحور يعتمد مسيطر دقيق لمجمع شمسي

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Abstract

The present work is a design and implementation of a compact single-axes solar tracking system. The hybrid system a combination from mechanical and the electronic parts. A tracking system are used to track the sun position and let the solar collector facing the sun as long as possible. The single axis tracking system has the ability to rotate the solar collector in horizontal axis and in both clockwise and anticlockwise .The electronic system contains a microcontroller board connected to dual sensors and the output signal from the microcontroller will be input to one-axis motor. The experiments conduct for flat plate solar water collector in the first case non-tracking system and secondly case using tracking system. The experimentally results that the average obtained falling solar radiation on solar collector in the first case and the second case during the same time is (616 watt/m2, 725 watt/m2) respectively .This means an increase about 17.7 % at using tracking system and the average useful heat gain output of solar collector during the same time is (65.8 watt, 85.5 watt) respectively it mean increased about 30.4 % at using tracking system.


Article
PREDICTION THE EFFECT OF MILLING PARAMETERS UPON THE RESIDUAL STRESSES THROUGH USING TAGHUCHI METHOD
تخمين تاثير متغيرات عملية التفريز على الاجهادات المتبقية من خلال استخدام طريقة تاكوشي

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Abstract

The important role in the performance of machined parts and structures is residual stresses, namely, in the following aspects corrosion resistance, fatigue life and part distortion. The aim of this research was to predict the residual stresses in aluminum alloy Al-6061 workpiece after machining; this prediction of residual stresses was applied with different value of cutting speed, feed rate and depth of cut using Taguchi method. The model is verified with experimental measurements of residual stresses. With the analytical model presented in this work, Feed rate is the most important variable that affect on maximum residual stress after that cutting depth and rotational speed substantial reduction in computational time is achieved in the predictions of residual stresses. The result of this research is the contribution of depth of cut, rotational speed and feed with respect to residual stress is (67.07, 24.8 and8.13) % respectively.


Article
NUMERICAL STUDY OF MIXED CONVECTION HEAT TRANSFER ENHANCEMENT IN A HORIZONTAL CHANNEL BY ADDING METAL FOAM BLOCKS
دراسة عددية لتحسين انتقال الحرارة بالحمل المختلط في قناة أفقية بإضافة كتل من رغوة معدنية

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Abstract

Mixed convection heat transfer in a horizontal channel supplied with metal foam blocks and partially heated at a constant heat flux is numerically investigated with air as the working fluid. The Brinkman-Forchheimer extended Darcy model is utilized to simulate the flow in the porous medium and the Navier-Stokes equation in the fluid region. The numerical investigations cover the Reynolds number range from 500 to 2000, heat fluxes varied from 500 to 6000 W/m2, and Darcy number 5 x10-2 to 1x10-3. Results show that the wall temperatures at each heated section are affected by the imposed heat flux variation, Darcy and Reynolds numbers variation. The variations of the local heat transfer coefficient and the mean Nusselt number are presented and analysed. The mean Nusselt number enhancement was found to be more than 85% for all the studied cases from the fluid case.


Article
THE MICROSTRUCTURE AND MAGNETIC CHARACTERIZATION OF NICKE FERRITE NANOFIBERSL
الخصائص التركيبية والمغناطيسية لألياف النيكل – الفيرايت النانوية

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Abstract

The nanofibers of nickel ferrite (NiFe2O4) was prepared by electrospinning technique. Nickel nitrate hexahydrate, iron nitrate nonahydrate, Polyvinylpyrrolidone (PVP) and N-dimethylformamide (DMF) were used as precursor materials. Crystallization behavior of the nanofibers was studied by X-ray diffraction (XRD). Nanofibers phases can change from amorphous to spinel ferrite depending on the calcination temperature at (500°C, 600°C, 700 °C) and crystallite size by Scherrer’s formula about (18.26 – 28.10) nm, while morphological and structural properties were investigated by scanning electron microscopy (SEM). Magnetization measurements were carried out on a vibrating sample magenometer (VSM), which revealed saturation magnetization of the samples were strongly dependent on the calcination temperature. Finally, our results showed that the electrospinning method leads to obtain nanofibers of nickel ferrite with good controllable stoichiometry at low temperature.


Article
COMPARATIVE STUDY BETWEEN SPECIFICATIONS OF TWO GROUPS OF THE TERNARY POLYMER BLEND USED IN STRUCTURAL APPLICATIONS
دراسة مقارنة بين مواصفات مجموعتين من الخلائط البوليميرية الثلاثية المستخدمة في التطبيقاتالهيكلية

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Abstract

In this work, preparation ternary polymer blends, by addition PMMA to the two groups of binary polymer blends (98%Epoxy: 2%NR) and (95%Epoxy: 5%NR). Mechanical properties for all prepared samples were studied. The results of this research showed that the ternary polymer blends which have the ratios (93%Epoxy: 2 %NR: 5%PMMA) or (90%Epoxy: 5 %NR: 5%PMMA) have the best results in fracture strength, young modulus, compressive strength, and hardness and the maximum values were at 5%PMMA, while elongation decreases with the addition PMMA to the blends. Moreover flexural properties values, impact strength and fracture toughness decrease with increasing in PMMA percentage for both groups, these polymer blends were characterized for morphology using scanning electron microscopy (SEM).


Article
STUDY THE MECHANICAL PROPERTIES AND CONSTANT FATIGUE BEHAVIOR FOR 7349 AL- ALLOY UNDER WET LASER PEENING
دراسة الخواص الميكانيكية وسلوك الكلال ثابت السعة لسبيكة الالمنيوم 7349 تحت التصليد الليزري المبلل

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Abstract

Laser peening (LP) is an innovative surface enhancement process. In which creates residual compressive stresses deep into part surfaces, to improve the resistance of metal. It has particularly effective in compressor blades. The compressive surface stresses resist the fatigue cracks initiation and propagation. This paper outlines an experimental study on the effect of water laser peening (WLP) on mechanical and fatigue properties of 7349 Al-alloy. The results show that the WLP can improve the mechanical properties and fatigue strength and life. The WLP treatments gave increase in ƃu 3.36% , in ƃy by 1.4% and in HV by 5% compared to the as-received mechanical properties .While the endurance fatigue limit was increased by 4% compared to the dry endurance fatigue limit .


Article
NEW CONSTRUCTION OF PNEUMATIC RESIDENTIAL ELEVATOR SYSTEM
بناء جديد لمنظومة المصعد الكهرو هوائي السكني

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Abstract

The current paper presents a new construction of an Electro-Pneumatic (EP) elevator system fully automated with Programmable Logic Controller (PLC) technology. This elevator represents as a new concept derived and evolved from the pneumatic-vacuum elevator as the idea of vacuum air is changed by the pressed air. The elector-pneumatic elevator is capable of transporting people between floors without using any cables, counter weight, or pulleys. An elevator system prototype constructed with three floors to elevate a 5kg payload with 1bar pressure had been proposed and controlled via a PLC controller of (LS-GLOFA-G7M-DR20A), 8 inputs, and 12 outputs. The PLC was programmed with Ladder diagram software. The idea of the proposed elevator system may be predicted to be widely spread in the low-rise residential buildings .


Article
EFFECT OF WAVY WALL LOCATION ON THE NATURAL CONVECTION IN AN ENCLOSURE CONTAINING A CONCENTRIC HEATED CIRCULAR CYLINDER
تأثير موقعِ الجدار المتموّجِ على الحمل الحراري الطبيعيِ في حيز يَحتوي على أسطوانة دائرية ساخنة مركزية

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Abstract

An investigation has been made to study numerically the effect of wavy wall locations on natural convection flow in a two dimensional enclosure filled with air containing a concentric heated circular cylinder. The external walls of the considered enclosure are maintained at a constant cold temperature (Tc) while the surface of the circular cylinder is kept at a constant hot temperature (Th). The numerical simulation, based on a finite element approach, is performed using program ANSYS version 11. The governing equations with boundary conditions are solved iteratively using the Tri-Diagonal Matrix Algorithm (TDMA). The current work is validated with previous numerical results available in the literature. The study aims to determine the effect of wavy wall location which is represented by varying the inclination angle (∅=0°, 90° and 180°), and undulation numbers (n=1 and 2) on flow field and heat transfer for four selected Rayleigh numbers (Ra=103, 104, 105 and 106). Streamline and isotherm contours are determined. The effect local Nusselt number along the hot surface of the circular cylinder is also examined in this study. The results indicated that the average Nusselt number at the hot surface of the cylinder increases with increasing the Rayleigh numbers and reduces when undulation number increases from one to two.


Article
AIR TEMPERATURE DISTRBUSION AND CONTAMMINATE CONCENTRATION IN LABORATORY UNDER IRAQI CLIMATE
تأثير مواقع السحب على توزيع درجات الحرارة وتركيز الملوثات داخل حيز مختبر عند ظروف المناخ العراقية

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Abstract

Ventilation is the main performance requirement in laboratory design as it has to guarantee a safe and comfortable indoor environment. standards and guidelines on laboratory ventilation often impose high ventilation rates, increasing the energy need for ventilation. This research focuses on the steady-state distribution of temperature and contaminate concentrations in a real environment which was a function of several factors such as the position of air exhausts. Here several different exhaust locations were investigated to determine the optimum exhaust positions. In this study, CO2 is used as an indicator of the concentration of pollutants inside tested room. Room concentration patterns for a laboratory were simulated with computational fluid dynamics (CFD) simulations by using (FLUINT6.3.26) and (GAMBIT V.2.4.6) computer programs for various exhaust locations. The computational results were validated with design data due to Iraqi cooling code (setup temperature and temperature difference from head to foot level). The numerical results showed that the exhaust grills located near the ceiling resulted in lower pollutant concentrations than the corresponding exhausts near the floor.


Article
THE EFFECT OF CORROSION-MUD TREATMENT ON FATIGUE ACCUMULATED PROPERTIES USING 7049 AL-ALLOY
تأثير معاملة التأكل الطيني على خواص الكلال التراكمي باستخدام سبيكة الالمنيوم 7049

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Abstract

The present work deal with the effect of corrosion-mud on constant fatigue and accumulated using 7049 aluminum alloy. Experimental results observed that fatigue life and strength strongly effect by corrosion-mud treatment. The (fatigue life reduction factor percentage) FLRF% can empirically expressed by the equation The fatigue strength was reduced to 10% due to mud corrosion fatigue interaction. It was indicated that Miner rule underestimated the mud corrosion fatigue life interaction.


Article
NON-LINEAR FREE VIBRATION ANALYSIS OF COMPOSITE LAMINATED PLATES
التحليل اللاخطي للاهتزاز الحر لصفائح طبقية مركبة

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Nonlinear free vibration analysis of composite laminated composite thin plate is studied in present work. Numerical solution using Ansys finite element program (Mechanical APDL 15.0) is used to investigate the effect of strain nonlinearity on the natural frequency of these plates. Design parameter is changed to investigate their effect on natural frequency of the plate such as lamination, aspect ratio, lamination angle and number of plies. An experimental work is programed to manufacture and test the mechanical properties and natural frequency of the plate for two boundary conditions (CCCC) and (CFCF) to compare the results with those obtained from numerical analysis. Numerical results are close to those obtained experimentally; maximum discrepancy is 4.04% for symmetric (CFCF) boundary condition and 5.08 % for an-symmetric (CFCF) boundary condition .


Article
MULTI-OBJECTIVE OPTIMIZATION OF WIRE EDM PARAMETERS BY APPLYING MOORA TECHNIQUE
الامثلية لمتغيرات التشغيل بالتفريغ الكهربائي باستخدام تقنية التحليل النسبي

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Abstract

The application of optimization techniques is essential for a manufacturing unit to respond effectively to ruthless competitiveness and increasing demand of quality product in the market. In this study, multi-objective optimization on the basis of ratio analysis (MOORA) technique was used to solve different decision-making problems and optimize the machining parameters in the wire electrical discharge machining processes for different materials. Five decision making problems requiring determination of optimum machining parameters using different techniques are considered in this paper. In all these cases, the obtained results using the MOORA technique compared with those suggested by the past investigators and the results demonstrate the simplicity, suitability, possibility, and flexibility of this technique when finding the solution for different complex decision-making problems during machining setting.

Keywords

Machining --- WEDM --- MOORA --- Multi-Optimization


Article
BUOYANCY EFFECT STUDY ON CONVECTIVE ENHANCEMENT FOR VARIOUS BASE NANOFLUID IN AN ENCLOSURES
دراسة تأثير قوة الطفو على تحسين الحمل الحراري لموائع نانوية مختلفة لمحتوى مغلق

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Abstract

Buoyancy-driven heat transfer convection enhancement in a two-dimensional enclosure, for two cases boundary conditions: (isothermal and linearly varying) temperature differential heated walls utilizing Nano fluid is studied numerically. In this study, three various base fluids (water, ethylene glycol, or oil) based with (CuO) nanoparticles are tested. Calculations of heat transfer rates were accomplished for a range of Rayleigh number (103 ≤Ra≤106), Prandtl number is taken as (Pr = 6.7, 204, and 10959), and solid volume fraction (0 % ≤ϕ≤ 10 %). Numerical computations are carried out for different combinations of relevant parameters involved in the study. Results showed that the heat transfer rate increases by increasing the volume fraction of the Nano fluid for all types of base Nano fluid considered. The increment in average Nusselt number is strongly dependent on the basic fluid and boundary condition chosen. The heat transfer rate also increases with increases of Rayleigh number, and Prandtl number. Based on the present results, oil-base nanoparticle in an enclosure with the isothermal temperature walls is preferable to attain overall heat transfer enhancement. Also, the enhancement in heat transfer with (0.1) solid volume fraction of (CuO) particles based with different basic fluids such as (water, EG, or oil) increases (26.7%, 28.8%, and 32.94%) respectively for low (Ra) as compared to the base fluid. For verification of current study, the results have been compared with the recent studies at the same boundary conditions and are a good agreement.


Article
PITTING CORROSION STUDIES OF MG-BEARING HYPEREUTECTIC AL-17% SI ALLOY
دراسة التأكل النقري لسبيكة الالمنيوم- %17 سيليكون فوق اليوتكتيكية المحتوية على المغنيسيوم

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Abstract

In this study pitting corrosion is investigated in hypereutectic Al- 17wt% Si alloy bearing magnesium . Many alloys were prepared by die casting with adding different percentages of magnesium : 1 wt%, 4wt% & 9 wt% to the Al-17%Si alloy in order to study the influence of magnesium addition on the corrosion behavior and pitting properties in 3.5% NaCl solution. Results of microstructure examination show that primary silicon (Si) and eutectic silicon in base alloy was more susceptible to pitting corrosion compared to the other alloys containing magnesium . It was found that the corrosion rate of alloy Al-17%Si bearing Mg (in all percentages) was lower than that of base alloy. The corrosion potential shifts to less negative value ( to more noble direction) and Epit to more positive value with increasing Mg content to 9%wt. It means that the addition of Mg to Al-17% Si alloy improves resistance to pitting corrosion and that no pitting appears in passive region during the cyclic polarization test.

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