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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: 2018 volume:18 issue:2

Article
THE EFFECT OF NATURAL MATERIALS ON MECHANICAL PROPERTIES OF COMPOSITE MATERIALS
دراسة تأثير المواد الطبيعية على الخواص الميكانيكية للمواد المتراكبة

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Abstract

This research studied the mechanical properties of orange and pomegranate shells powders reinforced unsaturated polyester with different weight fractions %Wf. The composite specimens were prepared by hand lay-up technique and sectioned according to (ASTM) for tensile, impact, bending and compression tests to obtain modulus of elasticity, ultimate tensile strength, elongation percentage, compression strength, impact energy and fracture toughness of the composite specimens. The results showed that the composite specimens reinforced with pomegranate shells powder give high mechanical properties compared with composites specimens reinforced with orange shells powder.


Article
MICROSTRUCTUR AND MICROHARDNESS OF LASER CLADDING Ni BASED ON COLD ROLLED STEEL
البنية المجهرية والصلادة الدقيقة للاكساء بالليزر لاساس نيكل على الصلب ألمدرفل على البارد

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Abstract

A study is reported of the laser cladding of a nominal composition of Ni 5 wt% Al on cold rolled low carbon steel (0.16 wt% C), using a high power continuous CO2 laser. The severe rolled microstructure of steel was changed considerably at the heat affected zones under all specific energies. The cladded coatings showed the presence of ɣ solid solution and β (NiAlFe) phases. Sound metallurgical bonding with absence of porosity and cracks was observed between the substrate and the clad coat at specific energy higher than 80 J/mm2. The ferrite and pearlite microstructure of the substrate was changed to martensite at the region adjacent to the clad interface. It followed by large grains of austenite/ferrite and pearlite (grain growth zone), fine grains of austenite/ferrite and pearlite (recrystallization zone) and very small zone of relatively small change of cold structure (recovery zone). The last zone was confirmed by micro hardness as a recovery zone. This investigation confirms clearly the possibility of formation different structures of grain growth, recrystallization and recovery at the laser heat affected cold rolled low carbon steel. The observed results suggest the developing of a new technique to obtain tentative functionally graded material.


Article
HARDNESS AND FRATURE TOUGHNE OF PLASMA SPRAYED ZIRCONIA-CERIA-YTTRIA THERMAL BARRIER COATINGS
الصلادة وعساوة الكسر لطبقات الرش بالبلازما للحواجز الحرارية للزركونيا-سيريا-ياتريا

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Abstract

Several studies have been made during the recent years to evaluate the plasma sprayed yttria partially stabilized zirconia thermal barrier coatings but less attention were undertaken on ceria-yttria stabilized zirconia. In this study, zirconia- 20 wt% ceria-3.6 wt% yttria thermal barrier coatings were produced by air plasma spraying deposited on IN 738 LC superalloy substrate. The objective of this study is to analysis the distribution of porosity, hardness and fracture toughness on the deposited coatings. Under optimum plasma spraying conditions, it is dangerous to consider the mean values of hardness and fracture toughness. The distributions of hardness and fracture toughness are highly scattered. The Weibull distribution is the main parameter to describe the plasma sprayed coatings hardness and fracture toughness.


Article
THE EFFECT OF TiO2 AS ADDITIVES ON PROPERTIES OF COMPOSITE MgO FOR BONE REPAIR
تأثير اضافة TiO2 على خواص الماد المركبة من MgO لترميم العظم

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Abstract

Magnesium oxide (MgO) is regarded as a biocompatible material. A composite material from MgO oxide prepared by mixing MgO powder with TiO2 (rutile phase) (2, 5, 10)Wt.% using powder metallurgy technique. It is used to be bioceramic material. The compressed samples were dried and sintered at (1200) ᵒC. porosity measurement showed that the porosity decreasing with increasing TiO2% . X-ray showed the presence of Mg2TiO4 in the composite structure of MgO with (5, 10)%TiO2 samples. The mechanical study showed an increasing in compressive strength, hardness, wear resistance and biodegradation resistance with increasing TiO2% content in the limit of used percentage. The prepared composite material didn’t present antibacterial activity while previous researches showed opposite result because of using nanoscale particle size of MgO.


Article
OPTIMUM BUCKLING DESIGN OF CYLINDRICAL STIFFENER SHELL UNDEREXTERNAL HYDROSTATIC PRESSURE
التصميم الامثل لانبعاج الأسطوانة تحت الضغط الهيدروستاتيكي الخارجي

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Abstract

This paper present an investigation of the collapse load in cylinder shell under uniform external hydrostatic pressure with optimum design using finite element method via ANSYS software. Twenty cases are studied inclusive stiffeners in longitudinal and ring stiffeners. Buckling mode shape is evaluated. This paper studied the optimum design generated by ANSYS for thick cylinder with external hydrostatic pressure. The primary goal of this paper was to identify the improvement in the design of cylindrical shell under hydrostatic pressure with and without Stiffeners (longitudinal and ring) with incorporative technique of an optimization into ANSYS software. The design elements in this research was: critical load, design variable (thickness of shell (TH), stiffener’s width (B) and stiffener’s height (HF). The results obtained illustrated that the objective is minimized using technique of numerical optimization in ANSYS with optimum shell thickness and stiffener’s sizes. In all cases the design variables (thickness of shell) was thicker than the monocoque due to a shell’s thicker is essential to achieve the strength constraints. It can be concluded that cases (17,18,19, and 20) have more than 90% of un-stiffened critical load. The ring stiffeners causes increasing buckling load than un-stiffened and longitudinal stiffened cylinder


Article
EXPERIMENTAL AND NUMERICAL STUDY OF NATURAL CONVECTION BETWEEN TILTED WALLS WITH ATTACHED FINS
دراسة عملية ونظرية للحمل الحر بين جدارين مائلين بوجدود زعانف متصلة

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Abstract

The free convection between two tilted adiabatic plates with centered heated horizontal cylinder with attached plate fin was investigated experimentally and numerically. The experimental rig constructed from vertical adiabatic was filled with air plates with aspect ratio of (A= 12) tilted by angles of (15o, 30o, 45o, 60o, 75o, and 90o). A horizontal heated cylinder with diameter of (16 cm) subjected under constant heat flux of (100, 500, 700, and 1000 W/m2), the Rayleigh number ranging from (3.5 ×107 to 4.5 ×109). At the bottom of the rig left an opining with distance of (2, 4, 6, and 8 cm) but the upper left open to the atmosphere. The tested cases was of (without fin, smooth, triangular, square, and semi-circle fin) was attached to the right wall of the cavity. The numerical solution of the case was performed by solving the governing equations by ANSYS-FLUENT 14.0 package that dependent upon the finite volume method. The experimental results show that the Nusselt number increases with increasing Rayleigh number, decreasing the inclination angle, increasing heat flux and with increasing the bottom opining distance. Basically, the results showed that the using fins with any geometry will lead to increase the heat transfer rate. The optimum increasing in the Nusselt number was found by using triangular plat fin. Finally, the experimental data was compared with a numerical calculation and found that there is a good agreement in the same conditions


Article
EXPERIMENTAL AND NUMERICAL STUDY OF 6061-T6 AL- ALLOY FATIGUE LIFE USIFRICTION STIR WELDING NG
دراسة عملية وتحليلية لعمر الكلال لسبائك الالمينيوم6061-T6 الملحومة باللحام الاحتكاكي الدوار

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Abstract

Welded parts are often subjected to variable loads. Paper’s aim is to evaluate the fatigue characteristics of friction stir welding of AA6061-T6 alloy under variable loading and observed the influence of heat treatment for friction stir welding joint on the fatigue stress analysis. The microstructure of the welds alloy are studied before and after heat treatment. The friction stir welding was employed using milling machine with constant tool rotation (1000 rpm) and feed rate (20 mm/min). Artificial aging are made for aluminum friction stir welded alloy using electrical furnace at temperature of 500ºC for 20 min. Quenching at 190ºC for 4 hr. via water is followed the aging process. Fatigue test were done for specimens (base metal, friction stir welding alloys before and after heat treatment) to obtain the S-N curves for each case. Finite element via ANSYS software is used to analysis the FSW (temperature, Von-Mises stress, deformation in the welded zone and contact friction stress distributions) and Fatigue test (fatigue life, fatigue damage, fatigue safety factor, biaxiality indication , equivalent alternating stress and stress intensity factors) where the general thermo-elasto plastic relation produced under thermal and mechanical loads with isotropic, kinematic and mixed hardening rule in three dimensional problems is proposed. The results shown that the heat treatment for the friction stir welded alloy would be increased the fatigue strength of the welded plate that the number of cycles of base metal (AA6061-T6) was 1.2×106 and the number of cycle for welded joints without heat treatment was (0.9×106), where the number of cycles was 1×107 with heat treatment with quenching within 4hr. also it can be concluded that, the fracture opening mode (mode I) is exist in the un heated welded alloy and disappeared with heating treatment .


Article
IMPROVING RUTTING RESISTANCE OF HOT MIX ASPHALT BY DATES KERNEL POWDER
تحسين مقاومة التخدد للخلطة الأسفلتية الحارة بواسطة مسحوق نواة التمر

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Abstract

In Iraq, the significant increase in the number of passenger cars and trucks (increased in axle loads) in addition to the unprecedented rise of temperature in the summer has increased the risk of permanent deformation of flexible pavement (Rutting) in recent times. Lower costs maintenance and extending serves life of flexible pavements are the main objectives of this study by improving rut resisting of it using the waste locally available materials (Dates Kernel Powder). The Superpave design criteria is used to determine optimum asphalt content at 4% air voids for hot mix with Lime Stone Dust and Dates Kernel Powder as a filler materials to three types of aggregate blend. Preparing 54 samples with dimension (400*300*50) mm at 110˚C compacted temperature to test it by Wheel-Tracking device at 40˚C, 50˚C and 60˚C. Based on wheel-tracking device results, it can be show that there was a significant decrease in the value of the Rut Depth when using the Dates Kernel Powder as an alternative to Lime Stone Dust as a filler materials in Hot Mix Asphalt and it can be used to improve the rut resisting; the maximum percent of reduction is 67.71 after 3000 cycle of passing at 60ºC and 49.35 as a minimum percent of reduction after 5000 cycle at 40ºC tested temperature, then it can be seen that the impact of Hot Mix Asphalt with Dates Kernel Powder is less at high temperatures than mixes with Lime Stone Dust on Rut Depth value.


Article
EFFECT OF TIC AND B4C ON MECHANICAL PROPERTIES OF AA7075 ALLOY FABRICATED BY POWDER METALLURGY
تأثير TiCو B4C على الخواص الميكانيكية لسبيكة الالمنيوم AA7075 المصنعة بميتالورجيا المساحيق

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Abstract

In this work, aluminum metal matrix composites (AMMCs) were fabricated by using powder metallurgy. AA7075 powder is reinforced with two different ceramic particles (TiC,B4C) with different weight fractions (2.5, 5, 7.5 and 10 wt.%). The composites were produced by powder metallurgy by preparing the powder, mixing, compacting and sintering. The particle size of unreinforced AA7075 about 100µm, while particle size of each TiC and B4C about 150 µm. The mixing process was done by planetary mixing setup rotating at 250 rpm for 2hr. by adding zinc stearate as an activator material with steel ball milling. However the mixture was compacted by hydraulic uniaxial press type (Leybold Harris No.36110) about 200 kg/cm² according to (ASTM-D 618). After compacting process, the mixture sintered at 475 °C for 2hr. by using electrical furnace with argon atmosphere. There are many examinations and tests were carried out for the synthesized composites material (AA7075/ TiC and AA7075/ B4C) such as examination of the microstructure, mechanical tests such as hardness and compressive strength, physical tests such as density and porosity. The results of this work showed that improving in physical properties (theoretical density, experimental density, porosity) and mechanical properties (Rockwell hardness and Compressive strength)


Article
IDENTICAL PARALLEL MACHINES SCHEDULING USING GENETIC ALGORITHM
جدولة المكائن المتوازية المتماثلة باستخدام الخوارزمية الجينية

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Minimizing the scheduling production time consider one of the most important factors for companies which their objectives is achieve the maximum profits. This paper studies the identical parallel machine scheduling problem which involves the assignment numbers of job (N) to set of identical parallel machine (M) in order to minimize the makespan (maximum completion time of all job). There are numerous troubles in solving the large size of “parallel machine scheduling” problem with an excessive jobs and machines, so the genetic algorithm was proposed in this paper which is consider an efficient algorithm that fits larger size of identical “parallel machine scheduling” for minimizing the makespan. Most studies in the scheduling field suppose setup time is insignificant or included in the processing time, in this paper both the sequence independent setup times and processing time were considered. The solutions of algorithms are coding in (MATLAB). A numerical example of (11) jobs are schedule on (3) machines to demonstrative the effectiveness of algorithm solution. The result show the algorithm can effectively solve large size of scheduling problem and given the best schedule with minimum makespan


Article
IMPROVEMENT OF MECHANICAL PROPERTIES OF ALUMINUM ALLOY 6061 –T6 WELD JOINT USING DC PULSED GAS TUNGSTEN ARC WELDING (PGTAW)
تحسين الخواص الميكانيكية لوصلات لحام من سبيكة المنيوم 6061 –T6 بطريقة نبضات التيار المستمر للحام القوس الكهربائي بقطب التنكستن

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The effect of DC pulsed GTAW method factors on mechanical properties of Aluminum alloys 6061–T6 is proves. Throbbed GTAW on the sheet having dimension of (200* 100* 5mm) is implemented at variable pulse current (150, 160, 170, 190) and constant frequency to get numerous connected joints by electrode type" ER4043 (Al Si5) as a padding metallic and argon as protective gas and compared with base current GTAW welding at D C current at 90 amps. The welded pieces are examined by X-ray radiography. The welded joints were treated by heat, the joints heated for half an hour in the furnace to 150 C° then cooled in the air to release the residual stresses. Mechanical quality of the weld joints. Microstructural categorizations, Micro hardness, enduring stress are examined. Consequences exposed that a common decline of mechanical properties of TIG welded joints conveyed 34% analogies with parent metal while the PGTAW joined offers better mechanical qualities analogy with of TIG joined in reductions conveyed 8.4% analogies with original metal this is because of the microstructure variations through the joining method and compressive residual stress generation in the weld zones. It has been found that by PGTAW improved the mechanical properties of welded joints which rely on current parameters


Article
PREPARATION AND INVESTIGATION OF SOME MECHANICAL PROPERTIES OF UNSATURATED POLYESTER RESIN REINFORCED BY HYBRID NANOPARTICLES
تحضير ومناقشة بعض الخصائص الميكانيكية لراتنج البوليستر الغير مشبع المقوى بدقائق نانوية هجينة

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Abstract

In this study, nano-composite of polymeric materials, prepared from unsaturated polyester resin (UP). Two groups of nanocomposites were prepared by Hand Lay-up method. The first group consists from (UP) reinforced by hybrid nanoparticles consisting of a mixture of zirconium oxide and yttrium oxide (30 mol%Y2O3- ZrO2) with particles size (83.98nm). The second group consists of (UP) reinforced by zirconia nanoparticles (ZrO2) with particle size (47.23nm). The effect of volume fraction (0.5%, 1%, 1.5%, 2%, 2.5%, 3%) of the nanoparticles additives on some mechanical properties of composites materials was studied also. The results shown that the values of the flexural modulus, impact strength and fracture toughness increased, as the volume fraction ratio of the nanoparticle increased for both groups of nanocomposites, while flexural strength values decreased with the increased the volume fraction ratio of the nanoparticles for both groups of nanocomposites also. As well as, the unsaturated polyester resins reinforced by hybrid nanoparticles has higher mechanical properties as compared with their counterparts of composites reinforced by zirconia nanoparticles only. The morphological formation of the fracture surface showed a close interconnection between all components of the prepared polymeric compositions. This reinforce a good compatibility between unsaturated polyester resins and reinforcement nanoparticles, which enhancement the mechanical properties.


Article
THE INFLUENCE OF LASER PEENING PULSE NUMBER ON HARDNESS, RESIDUAL STRESS AND ADHESIVE WEAR OF AISI 316l STAINLESS STEEL
تأثير عدد نبضات القذف بالليزرعلى الصلادة والاجهادات المتخلفة والبلى الالتصاقي للفولاذ المقاوم للصدأ AISI 316l

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Improvement of Wear adhesive properties using laser peening treatment at varied number of pulse of Austenitic stainless 316L is studied. According to typical ASTM G99-05 number of wear inspection test are prepared in dimensions 20x10 mm then compiled into four groups. The surface test of three groups is exposed to a number of laser pulse 1, 2, 4 pulses respectively by laser peening without coating. Microstructure, residual stress, hardness, is tested. Wear test using pin on disc method are used on all groups of specimens at two parameters, diverse times 10 ,20,30 min with constant load 1kg , and divers load 1,1.5, 2 kg with constant time 10 min. from results it was concluded that decrease in hardness and rises in ductility shared to increases in wear properties for the original metal and leaser peening participated to rise in the wear resistance due to increase in hardness , compression residual stress and the heterogeneity of the evidence in the microstructure ,four pulse laser peening give the lowest wear rate comparing with one pulse which witness decreases in wear rate.


Article
INVESTIGATION SOME PROPERTIES OF (ZN-NI-SIC) COMPOSITES COATING ON LOW CARBON STEEL
تحري بعض خواص طبقة الطلاء (Zn-Ni-SiC) المترسبة على نماذج من الفولاذ واطئ الكاربون

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This work represents an attempt to introduce further improvement on the properties of these 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.

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