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: 2011 volume:11 issue:3

Article
EFFECT OF BOUNCING AND PITCHING ON THE COUPLED NATURAL FREQUENCY OF AN AUTOMOBILE
تأثير الحركة العمودية والتأرجحية على الترددات الطبيعية المزدوجة للسيارة

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Abstract

ABSTRACT This paper describes a unique solution of bouncing and pitching interactions, in which it play an increasingly significant role in vehicle. While the behavior of vibrating system has motivated numerous experimental and numerical works, very few studies have been devoted to the case of vibration of car. This paper presents an investigation of bouncing – pitching effects, which is of strong interest for vibration of vehicle. The prediction of the natural frequencies in the car is thus a challenging task. This paper have a novel discussion of the dynamic behavior (natural frequencies and mode shapes) of vehicle and the relationships between the coupled natural frequency of the car. This work is theoretical and finite element method via ANSYS software study of dynamic performance of vehicle which is consists of two masses (body of car and tire) . The paper deals with obtaining the vibration characteristic of an automobile analyzed as system without damping due to the effect of bouncing and pitching. The focus of the vibration analysis is to obtain the eigenvectors, and the corresponding natural frequencies of the system. Good agreement is evident between the theoretical and finite element method in which the discrepancy between the two methods is about 0.05% for bouncing and 0.2% for pitching model. Also, it can be deduced that the join between car and tire, the result of the natural frequencies are differed from that of the natural frequency for the individual one, in which the higher frequency is increased and decreased the less one.


Article
RESIDUAL ELASTO-PLASTIC STRESSES ANALYSIS OF POLYMERIC THICK –WALLED PRESSURIZED CYLINDER
تحليل الاجهادات المرنة – اللدنة المتبقية للاسطوانه البوليميرية السميكة الجد ا رن والمعرضة لضغوظ داخلية

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Abstract A theoretical solution is presented for polymeric thick pressurized cylinder, where material behaviour is described by the modified Von Mises criterion. The solution is carried out using different values of Yc/Yt ratio to demonstrate their effects on the plastic zone radius and on the radial and hoop stresses also on the residual stress components. The results is indicated that the influence of α ratio or (Yc/Yt) ratio on the plastic zone radius and stress distributions is significant, and it can be shown that , when α ratio increases the plastic zone radius decreases , the value of α ratio has no effect on the value and distribution of radial stress, and when α ratio increases the level of the hoop stress increases in the plastic zone and decreases in the elastic zone and the value of α ratio is directly proportional to the value of residual radial and hoop stresses in the cylinder. A published finite element results give a reasonable agreement with the obtained results.


Article
PER FORMANCE IMPROVEMENT OF A TURBO SHAFT ENGINE USING WATER INJECTION
تحسين اداء محركات المحور التوربيني باستخدام حقن الماء

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Abstract

ABSTRUCT A theoretical study to calculate the performance of the turbo-shaft engine (TV3- 117 MT), used to power the helicopter (MI-17). It is clear that the engine works less efficiently in a hot ambient especially during takeoff because the engine at takeoff needs maximum power. The engine performance is also calculated after water injection at compressor entrance. A new mixture (water and air), the dew point temperature has also been calculated at compressor entrance and in every stage to ensure that no condensation of water vapor is take place on the blades of the compressor. To satisfy this aim the amount of water injection should not exceed (0.8%) of air mass flow rate depending on the permissible payload of the engine. The performance with water injection was calculated at different amounts of water injection (0.2 %, 0.5 %, 0.7 %, and 0.8 % of air mass flow rate with constant temperature (10 C0)).The results showed that an increase in the amount of water injection leads to decrease in the mixture temperature and to an increase in the specific heat at constant pressure. The percentage improvement in the performance for the specific power, thermal efficiency and specific fuel consumption at (Ta=55 C0 ) and • m =0.8% of air mass flow rate at the entrance of the compressor were (14.7, 12.6 and 11.3) respectively .


Article
FUZZY LOGIC CONTROL OF CRANE SYSTEM
المنطق المضبب للرافعات

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Abstract

ABSTRACT: Fuzzy logic defines rules that determine the behavior of the system using word descriptions instead of mathematical equations, fuzzy logic control algorithms can be used to solve problems that are difficult to address with traditional control techniques. In this research a fuzzy control strategy is proposed to control the stability of an crane work. It is beneficial that the fuzzy logic concentrates on the significance rather than the accuracy and the mechanism is applied without get in complex mathematics, therefore the only important thing here is the stability. The results of the four case studies indicate that the proposed control strategy is feasible with more simplicity and acceptance.


Article
STUD Y OF AIR -WATER FLOW INSIDE A 3-D CROSS JUNCTION
دراسة جريان المياه في العقد الثلاثية

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Abstract

ABSTRACT This study examines the flow of water and air in a cross junction by fluent under Ansys 12. Initially the problem will solve by using the less computationally intensive mixture model, and then turn to the more accurate Eulerian model. In this study which is using flow of water and air inside closed and vertical conduit as cross junction so the flow is water and air as mixture in inlet of pipe and the mixture leaves the pipe in three outlets as shown in Figure (1), also the phase of the air is assume to be bubble flow, so the diameter of the bubble of air will be present. The slip velocity equation need to solve since there will be significant difference in velocities for the different phases. The study used solid work programme to work the figure and then export it to fluent of Ansys. The study used the mixture model and Eulerian model to investigate the distribution of air inside the cross pipe and the where of the effect of static pressure inside the cross conduit for design. Also the contour of velocity magnitude is used to know the moving and distribution of the flow. The comparison between the two model are happen to know the range of converge for results for two model


Article
I NVESTIGATION OF THE ADDITIVES FOR CHANGING ON PHASES AND CORROSION BEHAVIOR OF SHAPE MEMORY ALLOYS
دراسة تاثير الاضافات لتغير الاطوار ومقاومة التاكل لسبائك الذاكرة

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Abstract

ABSTRACT Nickel-Titanium shape memory alloy (Nitinol or NiTi) is a fascinating material for dental applications. In this work the alloy has been prepared by powder technology and the effect of Mg and Zn additives has been studied on the corrosion rate, in artificial saliva. Samples (without additives) were prepared using powder mixture of 55 wt.% Ni and 45 wt.% Ti by blending in a ball mill for two hours, then compacted at 800 Mpa, and then sintered at 950 oC for 9 hours under controlled atmosphere (argon). The same approach was made for the samples with 0.1, 0.2 and 0.3 wt% of Mg and Zn additions. XRD test shows that the sintered samples are consisting of two phase's martensite and austenite at room temperatures.From the results; it was found Zn additives increase the corrosion rate while Mg additives decrease the corrosion rate.


Article
OPTI MIZATION OF THE SQUEEZE CAST Y2O3/Al-Si COMPOSITES BY MERIT RATING METHOD
امثلية متراكبات Y2O3/Al-Siالمحضرة بواسطة السباكة بالعصر

Authors: Osama Sultan Muhammed
Pages: 466-474
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Abstract

ABSTRACT In this paper, Y2O3/Al–Si composites are prepared by squeeze casting process and merit rating method is used to optimize the squeeze casting process parameters. A wear rate and hardness tests were conducted and the density is calculated for the resulted castings. The primary objective is to use merit rating method to find a better group of parameters that give the good balance of high density and hardness with low wear rate. The evaluated squeeze casting parameters are pouring temperature, die temperature, and squeeze pressure. The experimental and analytical results showed that the merit rating method was successful in determining the group of parameters that give an optimum balance of properties. Also it showed that if the difference in any property values among specimens is high, it can affect the selection process with the importance sequence.


Article
WEAR RATE BEHAVIOR OF CARBON/EPOXY COMPOSITE MATERIALS AT DIFFERENT WORKING CONDITIONS
سلوك معدل البلى لمادة متراكبة ايبوكسي/الياف كاربون عند ضروف عمل مختلفة

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ABSTRACT A Pin -on- Disc wear testing rig of variable sliding speed with varying load and sliding time has been used in this research to measure the wear rate of the carbon/epoxy composite specimens at dry and wet working conditions. In this research the composite specimens made from the epoxy used as a matrix and the carbon fiber with length ≤ 3mm and volume fraction (3, 6 & 9 vol. %) as reinforcement. The results show that the wear rate of composite specimens increase in nonlinear relationship with increase the applied load, sliding speed and sliding time and decrease in nonlinear relationship with increase the volume fraction of carbon fiber. The results also show that the wear rate for the epoxy reinforced by carbon fibers for dry working conditions was higher than the wear rate for wet working conditions. The maximum percentage reduction in wear rate was 30% for wet working conditions and 18.5 % for dry working conditions at 9 % Vol. of carbon fibers when compared with the neat epoxy.


Article
Study the Mechanical Properties of Epoxy Resin Reinforced With silica (quartz) and Alumina Particles
دراسة الخواص الميكانيكية للايبوكسي المدعم بدقائق سليكا (كوارتز) والالومينا

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Abstract In this work the mechanical properties of polymer composites reinforced with ceramic particulates are investigated. The epoxy resin used as a Matrix material is Ep-10 and the reinforcement particulate materials are silica with particle size (53-63)μm and alumina with particle size (106-150)μm ,and having weight fraction of 20%, 30% and 40% respectively. Specimens of the matrix material and the six types of composite materials were subjected to tensile, compression, bending, impact and hardness tests. Experimental tests results indicate that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity is directly proportional to the weight fraction of reinforcement material and that alumina composites have higher modulus of elasticity than silica composites with equivalent weight fraction .The highest modulus of elasticity is that of the composite with 40 % alumina, which is 182% higher than that of the matrix material. The tensile and bending strength of the matrix material were found to be significantly higher than those of the composite material while composites with 30% and 40% weight fraction reinforcement martial have marginally higher compressive strength than the matrix material. Test results also indicate that material toughness, fracture toughness and hardness of the composite materials are significantly higher than those of the matrix material. The enhancements in these properties are found to be directly proportional to the weight fraction of reinforcement materials. These properties of composites reinforced with alumina are significantly higher than that of composites reinforced with equitant silica(quartz) content. The highest material toughness, fracture toughness and hardness are that of the composite with 40 %alumina.


Article
THEORETICAL AND EXPERIMENTAL STUDY FOR THERMAL STRESSES DISTRIBUTION IN (TIG SPOT) WELDS OF AL-MG ALLOY (5052).
د ا رسة عملية ونظرية لتوزيع الاجهادات الح ا ررية في وصلات ( اللحام النقطي لسبيكة الالمنيوم – مغنيسيوم ( 5052

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Abstract In this study Tungsten Inert Gas spot welding (TIG Spot ) is carried out for Al- Mg alloy (5052) with the overlap join for sheet of 1mm thickness. Welding process is carried out at different welding currents and times at a constant arc length (1.6mm). optimum welding conditions are determined depending on maximum shear force of weld joint. Theoretical work is by using finite element method by utilizing program (Ansys 5.4 ) to calculate thermal stresses in TIG Spot at welding currents (80,100,110,120)Amp and welding times(6,7,8)sec.


Article
IMPROVEMENT THE HARDNESS AND WEAR OF (ZN-NI) COATING LAYER BY ADDING SILICON CARBIDE
د ا رسة الصلادة والبلى لطبقة الطلاءZn-N)i)المترسبة على نماذج من الفولاذ واطئ الكاربون بأضافة كاربيد السيليكون

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Abstract: This work represents an attempt to introduce further improvement or the properties of theses coatings, although the (Zn-Ni) deposition is known to be an anomalous electrodeposited process , where added Ceramic materials is (silicon carbide) ,with very good mechanical properties . Carbon steel samples were coated with (Zn-Ni) and (Zn-Ni-SiC) particles with different particles size of silicon carbide once microscale (73μm) and another nanoscale (70-100nm) .After electroplating, these samples were analyzed by X-ray fluorescent to confirm all the content for each alloy


Article
EFFECT OF ANTIMONY TRIOXIDE THERMAL CONDUCTIVITY FOR POLYMERIC MATERIAL REINFORCED BY GLASS FIBERS
تأثير ثالث أُوكسيد الأنتيمون على الموصلية الح ا ررية لمادة ب ولميري ة مقواة بألياف زجاجية

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Abstract . This research aimed to study the effect of flame retardant material addition namely antimony trioxide (Sb2O3) on thermal conductivity of composite material consist of conbextra epoxy (EP-10) resin reinforced by chopped E–type glass fibers with density (600g/cm2) .The effect of different percents of antimony trioxide (10%, 20%,30%) on thermal conductivity was investigated by using Fourier equation to calculate the thermal conductivity coefficient (k) for this composite material before and after addition of flame retardant material ,where the thermal conductivity value improved after added trioxide where it change from(0.35 W/m.ºC) before added antimony trioxide to (0.4 W/m.ºC) after addition (30%) from oxide at temperature (50 ºC) which the best value from oxide additive


Article
Effect of Tempering Temperature on Wear Rate of Steel 100Cr6
تاثير درجة حرارة المراجعة على معدل البلى لفولاذ 100Cr6

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Abstract This research aims to study the effect of quenching by oil with tempering at 180°C and 400°C on wear rate of 100Cr6 steel. A pin-on-disc technique was used to measure wear rate at different loads and different sliding times with constant sliding speed(2.199msec)and the hardness of steel dise was 45HRC. The results show that the wear resistance of the specimen quenched by oil and tempered at 400°C was more than the specimen quenched by oil and tempered at 180°C.


Article
تأثير التقوية بدقائق MgO على الصفات الحرارية والميكانيكية لراتنج الإيبوكسي

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Abstract This research aims to, first : to increased thermal insulation to conbextra epoxy (EP-10) by additive magnesium oxide (MgO) with (5 μm) particle size as a filler with different Weight percentages (10%,20%,30%) to resin and study the effect of this additive on thermal insulation of the resin . Fourier equation was used to calculate the changing in thermal conductivity coefficient (k) for conbextra epoxy (EP-10) before and after addition of magnesium oxide ,where the results show improved thermal insulation of the resin by reduced in thermal conductivity coefficient value after oxide addition , and the value of thermal insulation will increased with increasing of additive percentage of magnesium oxide ,where it change from(0.24 W/m.ºC) before added oxide to (0.13 W/m.ºC) after addition (30%) from oxide at temperature (40 ºC) which the best value from oxide additive . The second : to study the mechanical behavior of the resin after reinforced it by the above weight percentage of magnesium oxide and studied its effect on mechanical properties of the resin which included : impact strength , tensile strength , and compression strength . It has shown an improvement in these mechanical properties after reinforcement by magnesium oxide where the value of mechanical properties will increase with increasing percentage of reinforcement. Impact strength increased from(30Kj/m2) to (39Kj/m2) , and tensile strength from(60Mpa)to (74Mpa), and compression strength from(132Mpa)to (146 Mpa), for reinforcing percentages 0% and 30% from magnesium oxide respectively .


Article
Effect of Thermal Spray Parameters on Wear Resistance for Medium Carbon Steel
تأثير عوامل الرش الح ا رري على مقاومة البلى للفولاذ متوسط الكربون

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Abstract This research was conducted following the process of coating by thermal spray flame technology through the use of a mixture gas composed of oxygen and acetylene for the purpose of obtaining a surface layer of ceramic coating on the surface of the medium carbon steel type (AISI 1050), provides an increase in the surface properties of the metal which is represented by wear resistance. The research carried out in three successive stages, the first stage included the preparation of the surface of specimens as well as the preparation of powder coating and analysis of chemical components of the specimens and coating powders. While the second stage included the implementation of the connector coating process (nickel - aluminum) and coating the main (alumina) using a flame spray coating process conducted in different ways for each specimen by change in spraying factors, which included the surface roughness of the base specimens, the temperature of the surface of the base specimens before the coating process, the distance between the spray gun nozzle and the surface of the specimens and thickness of the coating. The third stage included the testing of standard tests, which includes adhesion test, check wear and roughness of different coatings in addition to a microscopic examination of the successive layers of coat and surface basis. It has been reached on the best variables that give the high adhesion and the lowest wear rate, where the results showed that the increase of roughness from (0.85 μm) to (10.50 μm) led to the low rate of wear by up to about (51%) more than half, The best temperature of the heated surface of the foundation before the coating process to obtain the lowest rate of wear and higher adhesion ranging from (200 C º) to (300 C º). While the optimal distance between the spray nozzle and the surface of the specimen ranging from (150 mm) to (200 mm) and thickness optimized for coating ranging from (0.15mm) to (0.5mm) for the best coating with the lowest wear rate.

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