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:3

Article
EFFECT OF SINTERING TEMPERATURE ON PHYSICAL PROPERTIES AND CORROSION BEHAVIOR OF COMPACT (AL-4.5%CU- 1.5%MG) ALLOY
دراسة تأثير درجة حرارة التلبيد عل الخواص الفيزياوية والسلوك التاكلي لمكبوسة من سبيكة ( ألمنيوم-4.5% نحاس –1.5% مغنيسيوم)

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Abstract

This work aims to study the effect of sintering temperatures on physical properties (density and porosity) and corrosion behavior of compact(Al-4.5%Cu-1.5%Mg) alloy in 3.5% NaCl solution at room temperature using cyclic polarization method. Powder technology was used to prepare this alloy by mechanical mixing of Al, Cu and Mg powders in a ball mill for 6 hours to ensure a homogenous distribution of powders in the mixture. Mixed powder was compacted by using single action pressing at (450 MPa) then followed directly by sintering process at different temperatures (520,540,560,580 and 600ºC) for one hour in vacuum furnace under the effect of inert gas condition. Density ,porosity and microhardness measurements were performed to find the best sintering temperature. Tafel extrapolation method and cyclic polarization tests were conducted for all sintered samples. It was shown that the highest density and micro hardness were at sintering temperature 560ºC. It was found that the pitting corrosion resistance enhances with increasing sintering temperature up to 560ºC and afterword it drops again at higher temperatures (580 and 600ºC).


Article
FUNCTIONALIZED TITANIUM DIOXIDE NANOPARTICLES - NYLON 6 NANOCOMPOSITE MEMBRANE FOR IMPROVED SALT REJECTION UNDER LOW PRESSURE WATER NANOFILTRATION
غشاء متراكب نانوي ثاني أكسيد التيتانيوم - نايلون 6 لتحسين طرد الاملاح تحت ضغط منخفض للترشيح النانوي للماء

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Abstract

In this paper, (Nylon-6) spider-net containing (dioxide titanium) nanoparticles were electro spun to produce nanofiber membrane with (TiO2 NPs). Characterization of the nanofiber membrane containing (TiO2 NPs) were done by (SEM) and (EDX) analyses. Pure (Nylon-6) nanofibers with an average diameter of (139 nm) were produced while (TiO2) additive gives membrane (Nylon/TiO2) with an average nanofibers diameter of (123 nm). (TiO2 NPs) with small amounts in (Nylon-6) solution were found which improve the hydrophilicity (antifouling effect) with water contact angle (5.7º), pure water flux (4800.45 Lm-2h-1) and mechanical strength (7.075 MPa). It was concluded that (Nylon-6/TiO2) antimicrobial (spider-net) which considered as a composite membrane with antifouling effect can be used in water filter applications. An improvement in the produced membrane mechanical strength was reached, also, rejection test of salt was achieved with rejection percentage of (76) and (71) for (Pb(NO3)2) and (NaCl) respectively.


Article
MATHEMATICAL MODEL DESIGN TO PREDICT THE FATIGUE LIFE BEHAVIOR FOR BEARING STEELS
تصميم موديل رياضي للتنبؤ بتصرف عمر الكلال لفولاذ المحامل

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Abstract

Conventional and ultrasonic fatigue testing is usually conducted under axial or rotating- bending loading. In spite of the differences in shape and design of the fatigue specimens, the stressed volume plays a mutual role in assessing the fatigue life. This is due to the fact that the probability of finding voids or inclusions, which are the sources of cracks, increases as the stressed volume increases. The fatigue life of bearing steel generally extends to the Giga cycle regime so conducting such fatigue testing in the laboratory is time consuming and costly. In this work, a model based on neural network techniques has been suggested to predict the fatigue strength of bearing steel. The input data for this model includes hardness, the stressed volume, stress ratio and number of cycles. The model captures reasonable trends and is able to estimate unseen experimental results on high strength bearing steel AISI 52100. Extrapolation has been conducted for the rolling contact fatigue life and the results show good agreement with the experimental data.


Article
DESIGN AND IMPLEMENTATION OF V – TROUGH TUBE SOLAR COLLECTOR TO IMPROVEMENT THE PERFORMANCE BY USING HYBRID NANOFLUIDS
تصميم وتنفيذ مجمع شمسي ذو أنبوب داخل قناة على شكل حرف V لتحسين الأداء باستخدام موائع نانوية هجينة

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Abstract

This article includes the design and improvement of the performance of V trough tube collector in solar heating systems by using hybrid nanofluids, when hybrid metal (Cu (20nm) +Al (20nm) +DW), hybrid metal oxide (CuO (50nm) +Al2O3 (50nm) +DW) and distilled water are taken as the working fluids. The effects of metal and metal oxides hybrid nanoparticles are taken into consideration on solar hybrid nanofluid heating system. In experiments two types of hybrid nanoparticles are used with volume flow rate (20 and 40 lit/hr) and four hybrid nanoparticles concentration ratios (i.e. 1, 2, 3 and 5 % vol). The distilled water used as base fluid. The working fluid with the higher thermal conductivity in V – trough tube solar collector could improve heat transfer compared with that of distilled water. The hybrid nanofluids (Cu (20nm) +Al (20nm) +DW) at 5 % vol and volume flow rate (20, and 40 lit/hr) indicated significant effects through the thermal solar characteristics values of FR(τα), – F RUL were 0.524, – 7. 276 W/m2. K, 0.551 and – 7.423 W/m2.k, while the hybrid nanofluids (CuO (50nm) +Al2O3 (50nm) +DW) were 0.473, – 6.183 W/m2. K, 0.492 and – 6.224 W/m2. K. The synergistic between nanoparticles and type of hybrid nanofluid are a key factor for heat transfer improvement, and improve performance of (V) trough tube solar collector. Use of hybrid nanofluids (Cu (20nm) +Al (20nm) +DW) and (CuO (50nm) +Al2O3 (50nm) +DW) as a working fluid could improve thermal performance due to high thermal conductivity for copper and aluminum. At high inlet temperature, this kind (V trough tube) of solar furnace could improve the thermal performance by hybrid nanofluids compared with distilled water.


Article
EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER INA HELICALED COILED PIPE
دراسة عملية لانتقال الحرارة الطبيعي في الانبوب الملتف حلزونيا

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Abstract

The research presents an experimental investigation on the steady state natural convection heat transfer for helical coiled pipes with a vertical orientation. Water is used as the working fluid for both the target fluid and the bath medium. The heat transfer characteristics have been studied for three helical coils that having three curvature ratio (0.056, 0.0625, and 0.115) and three coil pitches (12.5, 25, and 37.5)mm with a volume flow rate of the target fluid ranges (10-25)L/min and two constant bath water temperatures (70 and 90)oC. All the experiments were performed for Rayleigh number range (1.76*109 – 1.15*1012). The experimental data have been used in SPSS software to predicted the empirical correlation of outside Nusselt number as a function of Rayleigh number by using height of the coil as a characteristic length then using this empirical relation in a computer program that have written in Fortran 90 to predict the outlet temperature and compared with the measured one. The results show that the inner and outer heat transfer coefficients increase with increasing of curvature ratio (d/D) and the mass flow rate. Also the results show that the difference between the measured and predicted outlet temperature equal to 1.5oC.


Article
FREE VIBRATION ANALYSIS OF LAMINITED COMPOSITE PLATE USING NEW HIGHER ORDER SHEAR DEFORMATION PLATE THEORY
التحليل الديناميكي للصفيحة المركبة بأستخدام نظرية قص ذات رتبة عالية جديدة

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In the present work a theoretical analysis depends on the new higher order element in shear deformation theory for simply supported cross-ply laminated plate is developed. The new displacement field of the middle surface expanded as a combination of exponential and trigonometric function of thickness coordinate with the transverse displacement taken to be constant through the thickness. The governing equations are derived using Hamilton’s principle and solved using Navier solution method to obtain the natural frequency. The effect of many design parameters such as number of laminates, aspect ratio and thickness ratio on dynamic behavior of the laminated composite plate have been studied. The modal of the present work has been verified by comparing the results of shape functions with that obtained by other worker. Result shows the good agreement with 3D elasticity solution and that published by other researcher.


Article
THE EFFECT OF PULSED ND:YAG LASER WELDING ON SHEAR FORCE AND MICROSTRUCTURE FOR NITI SHAPE MEMORY ALLOY WITH 304L AUSTENITE STAINLESS STEEL WELDMENTS
تأثيرلحام الليزر النبضي على قوة القص والبنية المجهرية للحام السبيكة النيكل- تيتانيوم الذاكرة الشكل مع الفولاذ المقاوم للصدأ الاوستنايتي

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Abstract

Dissimilar welding of austenitic stainless steel AISI 304L to shape memory alloy SMA NiTi was conducted by utilized Nd: YAG laser beam welding technique. Both AISI 304ASS and SMA have the same dimension (80*20*0.5) mm. The experimental investigation included tensile shear test and microstructure. The results demonstrate that the maximum shear force found in the sample (No/10) reach (2552 N) which has the better laser parameters in this research (peak power of (2.25 KW), pulse duration of (2.4 ms), pulse repetition rate of (40 Hz), and welding speed of (8 mm/Sec). SEM with optical microscope demonstrate the solidification method along the fusion area various in different joints, where they become the planer shape to cellular and transformed the last to dendritic from intra-fusion welding area toward the center because towards weld area interface to weld centerline cooling rate will be rise in all SMA (NiTi) and Austenite stainless steel (ASS) sides.


Article
ANALYSIS OF MIXED-MODE CRACK TIP IN FUNCTIONALLY GRADED BEAMS BY USING XEFGM
تحليل الشرخ المركب في العوارض المتدرجة وظيفيا باستخدام الطريقه اللاشبكية XFEGM

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Abstract

An extended element free Galerkin method (XEFGM) has been adopted for crack propagation of for graded glass/epoxy beams (along X1) subjected to non-proportional four point bending. The incompatible interaction integral method and the sub-triangle technique for enhancing the gauss quadrature accuracy near the crack are employed to calculate the stress intensity factors. Numerical simulations have proved that XEFGM provides accurate results by less number of nodes (DOFs) in comparison with the conventional FEM under mixed-mode and non-proportional loading. MATLAB codes are used in obtaining the results of this research. The results have shown good the reliability, stability, and efficiency of present XEFGM and good agreements with the experimental works of crack propagation with using less nodes in compare with the relevant references.


Article
FATIGUE LIFE ENHANCEMENT OF AL-ALLOY7075 UNDER COMBINED LASER ANDHYDROFLUORIC ACID INTERACTION
تحسين عمر الكلال لسبيكة الالمنيوم 7075تحت تأثير تفاعل مشترك لليزر وحامض الهيدروفلوريك

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Abstract

Laser shock peening (LSP) is a technical method for generation the compressive residual stress. LSP has been shown to greatly improve fatigue strength and lifetime. A study of fatigue under a constant repeating bending stress has been conducted on AL-alloy 7075 alloy at a stress ratio (R= -1) and room temperature using laser peening technique with overlay hydrofluoric acid (HF) as a confinement acid layer and as a media to increase the penetration of laser pulses. Two groups of test have been considered. The first group (15 specimens) was examined under unpeened situation. The second group (15 specimens) was examined under acid laser peening (ACLP). All mentioned groups were tested to generate the S - N curve. hydrofluoric acid (HF) coating was used as a new technique to improve the properties of the AL-alloy 7075. The experimental data showed that the use of (HF) acid, as a coating material, largely increased the compressive residual stress at the surface. The results provided a substantial improvement in fatigue life improvement factor reaching to 80% for this new coating.


Article
AN EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF HEAT TRANSFER ENHANCEMENT FOR CuO-WATER NANOFLUID IN TURBULENT FLOW CONDITIONS
دراسة عملية وعددية لتحسين انتقال الحرارة باستخدام مائع نانوي (اوكسيد النحاس-الماء) في ظروف جريان اضطرابي

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In this paper, both experimental and numerical studies were performed in a fully developed turbulent region heat transfer of the CuO-water nanofluid in a horizontal 0.019m diameter, 1.5m long copper tube that subjected to a uniform heat flux at its outer surface. An experimental investigation was done to evaluate the heat transfer characteristics, friction factor and the pressure drop of the CuO-water nanofluid are conducted in the particle volume concentration range of 0.01% < φ < 2%, and Reynolds number range of 5020< Re < 19985. The thermal conductivity, specific heat, density and viscosity of the nanofluids were measured. In numerical study, the finite volume method using Ansys R.15, standard κ – ε turbulence model employed to solve the continuity, momentum, energy and turbulence equations in three-dimensional domains. The experimental and numerical results showing that the data were satisfied within a 1.7% maximum difference. The effects of the nanoparticle concentration with uniform heat flux on the enhancement of the heat transfer turbulent flow condition were presented. The Nusselt number (Nu) of the CuO-water nanofluid case was higher than that the base fluid by approximately 48.7%. However, the increase in the pressure drop ranged is about 18%. Finally, the results reveals that the CuO-water nanofluids could be considered as a good and alternative conventional working fluid in heat transfer applications.


Article
EXPERIMENTAL STUDY OF TWO-PHASE FLOW AROUND HYDROFOIL IN OPEN CHANNEL
دراسة عملية للجريان ثنائي الطور حول جنيح في قناة مفتوحة

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The purpose of this paper is to study the two-phase flow around hydrofoil. Experimental studies have been conducted in a channel with air-water flow for different angles of hydrofoil with different air and water discharges. The paper describes experiments carried out in the channel with the rectangular test section of 100 x 30 x 800 mm. The maximum inlet velocity at the test section for air is 1.115 m/s and for water is 0.022 m/s. These experiments have been aimed to visualize the two phase flow phenomena as well as to studies effect of pressure difference through channel with hydrofoil. All sets of flow data in this study were obtained using pressure transducer and visualization by video camera and recorded at multiple angles of attack (0o,15o and 25o) and different Water discharge (l/min) (20, 25, 35 and 45) and different air discharge (l/min) (10, 20, 30 and 40). When (α=0°) the flow is parallel to the hydrofoil surface and there is no vortex shedding behind the hydrofoil. When (α=15°) the flow separates from the upper-surface and the separation point moves towards the leading edge of the hydrofoil as the air water discharges increases. When the angle of hydrofoil (α=25°), the flow separates near the leading edge of the upper surface and large eddies are shed from both the upper and lower surfaces. For constant water discharge, the pressure difference increased with increased air discharge with the same angle of hydrofoil


Article
ANALYSIS AND PERFORMANCE OF A PROPOSED VARIABLE STIFFNESS SUSPENSION SYSTEM
التحليل والاداء لمقترح نظام تعليق متغير الجساءة

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A theoretical analysis of a proposed variable stiffness model of the suspension system is studied to improve the traditional suspension system. The fundamental idea of system focused on variable stiffness mechanism by added subsystem to suspension system depended on control rotating arm balancing the force between sides, it consists of a vertical control strut. The variation of the load transfer by rotate arm has spring and damper at another side of it where the point of rotation is supplement the body of car by sup-system as vertical support. The investigations of the variable by addition stiffness to the suspension system for improvement of performance better than the variable stiffness systems for equivalent or traditional. The expending principles to described the performance of the characteristic behavior of system are fewer car body acceleration to ride comfort and lower suspension and tire deflection for road holding considered.


Article
ANALYTICAL STUDY OF TORSIONAL VIBRATION EFFECT ON TURNING SHAFTS IN SUDDEN STOP CASE
دراسة تحليلية لتأثير اهتزازات الفتل على الأعمدة الدوارة في حالة التوقف المفاجئ

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The sudden stop of rotating shafts for any external & arbitrary reason due to develop of circumference distortions because of dynamic angular displacement & by dividing on static angular displacement produce ratio called ( SSRSR ) to undesired elevations . The response according to " Bernoli – Euler " theory in undamped torsional vibration , one – dimension bars & homogenous , continuous material of bars , hence ,derived response for time & pointed position (furrier functions ) , the result depend on shaft engineering directory & modulus rigidity of shaft material & which is get convergence for theory & practical results.


Article
INVESTIGATION SOME MECHANICAL PROPERTIES OF SELF CURED PMMA RESIN REINFORCED BY DIFFERENT TYPES OF NANO PARTICLES
الأستقصاء من بعض الخصائص الميكانيكية لراتنج البولي مثيل ميثا أكريليت المقوى بانواع مختلفة من الدقائق النانوية

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In the present research, study the effect of adding two different types of reinforcing particles, which included: nano-alumina (nano-Al2O3) and nano-silica (nano-SiO2), that added with different volume fractions of (1%, 2% and 3%), on the some mechanical properties of composite prosthesis complete denture base materials by using self (cold) cure poly methyl methacrylate (PMMA) resin as new fluid resin matrix . In this research the composite prosthetic dentures specimens consist of from two groups were prepared by using casting methods, type (Hand Lay-Up) method according to the types of reinforced particles which includes: the first group consists of PMMA resin reinforced by nano-alumina particles, and the second group consists of PMMA resin reinforced by nano-silica particles. The mechanical tests were performed on these specimens include compression test, impact test, and hardness test . The result of this study showed the values of (compression strength and hardness) properties increased with increasing the volume fraction of both (nano-Al2O3 and nano-SiO2) particles in PMMA complete denture base materials. While, the values of (impact strength) property decreased . Also the addition of (nano-Al2O3) particles has a noticeable effect on the most properties of composite material for prosthetic denture base specimens more than the (nano-SiO2) particles, except the impact strength property .

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