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.

Loading...
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:4

Article
EFFECT OF ADDITIONAL BOUNDARY CONDITIONS ON THE AXISYMMETRIC FREE VIBRATIONS OF OBLATE SPHEOIDAL SHELLS
تاثير الشروط الحدية الاضافية على الترددات الطبيعيةالمتتناضرة المحور للقشريات البيضوية المفلطحة

Loading...
Loading...
Abstract

ABSTRACT This research deals with the effect of using additional boundary conditions as well as the eccentricity ratio on the axisymmetric free vibrational characteristics of thin isotropic oblate spheroid shells. The formulation depends on the boundary matching method using the non – shallow shell theory. The oblate shell was assumed to be constructed from two spherical elements matched along the continuous boundaries. The additional boundary conditions under construction were clamped – clamped, clamped – free and pined – pined. It was found that the natural frequency of the shell with clamped – clamped additional boundaries was greater than other two types of the additional boundaries. On the other hand it was found that in the case of clamped – clamped boundary condition, the eccentricity ratio has an effect on the natural frequency greater than the other two cases, i.e, clamped – free and pined - pined cases, respectively.


Article
A COMPARATIVE STUDY BETWEEN THE INTERNAL AND EXTERNAL BONE FIXATION METHODS
دراسة مقارنة بين طرق التثبيت الداخلية والخارجية للعظام

Loading...
Loading...
Abstract

Abstract The basic goal of fracture fixation is to stabilize the fractured bone, to enable fast healing of the injured bone, and to return early mobility and full function of the injured extremity [1]. The computerized tomography scan slices of the femur bone of one patient were translated to the ANSYS V.(10) program and then the solid model (3-D) model was built and analysed by the finite element method under different loading conditions for each method of fixation. Finite element analysis would help to reveal stress pathways across the shaft of the femur bone and the sites of the 8 screws or pins fixed at the shaft of the femur above and below the fracture site. In the internal fixation method two types of screws' materials can be studied. Firstly stainless steel and secondly cobalt chromium. The stress distributions were studied for each screw material for different body weights. While in the external fixation method the stress distributions for only stainless steel pins were studied. The stress distributions for six pins or screws fixed at the fractured bone above and below the fracture site for each method of fixation were studied. The von mises stresses of the cobalt chromium screws fixed internally are less than the von mises stresses of the stainless steel for each of the body weight. The stresses of the pins fixed externally are greater than the stresses of the same screws fixed internally. When decreasing the number of the screws or the pins the stress values will increase; therefore when using eight screws or pins the stresses are less than those when used six screws or pins for each method of fixation (internal and external).


Article
NATURAL CONVECTION IN EQUILATERAL TRIANGULAR ENCLOSURE FOR THREE SITUATIONS WITH HEATING ELEMENT APPLIED AT DIFFERENT POSITIONS ON THE INCLINED SIDE WALL
الحمل الحر في حيز مثلث متساوي الاضلاع لثلاث اوضاع بوجود شريحة حرارية مسلطة على مواضع مختلفة من ضلعه المائل

Loading...
Loading...
Abstract

ABSTRUCT Laminar natural convection heat transfer and fluid flow due to heating element inserted at different positions over the inclined side wall of equilateral triangle enclosure has been analyzed numerically in this study. The enclosure has filled with air as a working fluid with Pr=0.71. The walls of the enclosure are insulated except an element on one side where the heat flux are applied. The value of heat flux ( q" ) are 10, 30, 70 and 100 Watt with corresponding Rayleigh number of 105, 106, 107, 108 respectively. The length of the heating element was taken as 10% of the triangular enclosure side wall length where the length of the wall equals to 10 cm. The governing mass, momentum and energy equations are applied to the enclosure and solved by finite element using commercial code (ANSYS 5.4) based on TDMA method. Three different situations (normal, side and inverse) of the triangular enclosure with different positions of heating element are examined in this study to obtain the maximum stream function. The results show that the maximum value of stream function and high rate of heat transfer occur for normal situation of the enclosure and when the heating element is applied at position2 (Po.2 is a distance over the inclined side wall which takes a position limited between 0.2L to 0.3L from the edge of the triangle enclosure).


Article
EXPERIMENAL STUDY ON THE PARAMETERS AFFECTING THE BENDING BEHAVIOR OF COMPOSITE PLATES
د ا رسة عمليه للعوامل المؤثرة على سلوك الانحناء لصفائح مركبة

Loading...
Loading...
Abstract

ABSTRACT In this paper the bending behavior of composite plates manufactured from polyester reinforced with fiberglass, jute fiber and eggshell powder is studied .The moisture effect on the plate bending behavior is investigated by immersing the specimens in salt water and distilled water for 7 days. Also the effect of type of edges fixture on the central displacement of the plate is investigated. The results showed that for the fiberglass composite plates the central displacement for the moist specimens is 3-4 times as that for dry specimens. For the eggshell powder composite plates, it is found that the stiffness of the dry specimens is greater than that of moist specimens by about three times. The moisture absorption shows no significant effect on the stiffness of the jute composite plate.


Article
PREDICTION OF YIELD STRENGTH OF LOW/MEDIUM CRMO FERRITIC STEELS USING ARTIFICIAL NEURAL NETWORKS
تخمين اجهاد الخضوع لسبائك الفولاذ الفريتي الكرومي الواطئ والمتوسط المحتوى باستخدام طريقة الشبكات العصبية الصناعية

Loading...
Loading...
Abstract

Abstract The yield strength of Low/Medium Cr- Mo ferritic steels has been analyzed by a well selected artificial neural networks (ANN) model using data sets obtained from ASTM publications. The qualitative and quantitative effects of chemical composition, heat treatment and test temperature have been studied. The proposed ANN model was obtained by applying averaging process to the first best three models. The first one consists of 24 input nodes (the input variables), 23 hidden nodes and the output node which is the target for the required yield strength. Among the previous variables, it was found that the heat treatment ones have the greatest contribution to the yield strength especially the tempering one i.e. the average contribution of about 15% was obtained


Article
MECHANICAL PROPERTIES OF COMPOSITE MATERIALS BASED ON EPOXY RESIN REINFORCED LOW CARBON STEEL
الخواص الميكانيكية لمادة مركبة ذات اساس راتنج الايبوكسي المقواة بالفولاذ الواطئ الكربون

Loading...
Loading...
Abstract

ABSTRACT This work aims to prepare a composite material based on epoxy resin reinforced by fiber and dust particle from low carbon steel with various volume fractions and so, studying their effect on tensile and flexural strength. Fibers from low carbon steel, with 0.20 mm in diameter and low carbon steel dust particles were used as reinforcement with a volume fraction of (0.8, 2.4, 4.0, 6.2, and 8.3 %). The results showed that the tensile strength increases as volume fraction increases, for both cases. But the reinforcement by dust particles has more tensile strength than fiber reinforcement. For example, at volume fraction 0.8 %, the tensile strength of fiber composite was 135 MPa, whereas tensile strength of dust particles was 158 MPa. Also the results of flexural test show that the flexural strength increases as volume fraction increases, for both cases, but in low carbon steel dust particles / epoxy composite, the flexural strength reaches a maximum value 417.23 MPa at volume fraction 8.3 %. This value is higher than that of low carbon steel fiber / epoxy composite.


Article
RELIABILITY OF NUMERICAL ANALYSIS OF COOLING CURVES IN THE FUSION ZONE OF SUBMERGED ARC WELDING (SAW) PROCESS
أعتمادية التحليلات العددية لمنحنيات التبريد في منطقة الانصهار لعملية لحام القوس الكهربائي المغمور

Loading...
Loading...
Abstract

ABSTRACT In this work, simulation of fusion welding technique to estimate the cooling curves and temperature distribution in submerged Arc (SA) welded workpiece was assessed. Numerical analysis by using Finite Volume Method (FVM), applied to three-dimensional heat transfer model to determine the cooling curve in weld metal zone. There is no reliable method for calculation such cooling rate as a function of welding current, voltage speed and arc transfer efficiency in metal joint geometry. Cooling rates are determined by affected of weld metal deposition in the fusion zone at different welding speeds (22, 23 and 25) cm/min, with constant welding current at 500 Amp and 40 voltages. The joint geometry of single-V- butt joint with one pass are used for half plate dimensions (150×150×18 ) mm, fixed with standard geometry of (ISO-2560). Cooling curves model which is confirming the capability and reliability of weld metal deposition in fusion zone with different welding speeds. The optimization of filling area (weld metal deposition) by FVM is determined in each welding speed having correct welding current to filling cell of weld area.


Article
BLANK SHAPE PREDICTION BASED ON FLATTENING APPROACH OF 3D COMPLEX SURFACES PRODUCED BY DIGITIZED DIES
ألتنبؤ بشكل الغفل بالاعتماد على مبدأ تسوية الاسطح المعقدة الثلاثية الأبعاد والمنتجة بواسطة القوالب المتقطعة

Loading...
Loading...
Abstract

Abstract One of the most important and well-known problems in sheet metal based industries is the blank design of complex 3D curved surfaces. Blank design determines both shape and size of the incipient blank. This paper introduces an inverse method for converting the given 3D curved surface of the product to its planar shape. The develped planar shape is based on changing the position of control points that determines the shape of the curved surface. The material is assumed to obey pure shear deformation mechanism to simplify the processing and to estimate the direction of motion of these control points. The devised method is a multi-step scheme to come up with the deformation steps of such surfaces. The blank thickness distribution was nominated as a process parameter to qualitatively judge the performance of the presented method using FEM technique. The results show that the presented method is a very subtle way in predicting the blank shape so that the thickness is evenly distributed across the predicted blank compared with conventional methods. The results also show that the presented method is a detour to simulate the deformation steps.


Article
THE SOLUTION OF LAMINATED COMPOSITE SPHERICAL SHELLS BY THE APPLICATION OF CHEBYSHEV SERIES
حل القشريات الكروية ذات الصفائح المركبة بتطبيق متسلسلات شبيشيف

Loading...
Loading...
Abstract

ABSTRACT The solution of Composite Spherical Shells subjected to different external loading and boundary condition are investigation and analysis by the application of the classical composite-material theory. In this research are used Chebyshev series in matrix form to reformulate the differential equations of equilibrium of a composite spherical shell . Two problem are solved by using Chebyshev theory, the first problem are solved laminated spherical shell under uniform external pressure with open ( "o=10o) , the results obtained for maximum stress is (5.298-5.563 N/m) and maximum moment is (1.189-1.99 N.m/m).The results are compared with available published results and confirmed mach well. The second problem is solved for a supported shells under unite edge line load with different ("o=30o and 80o ), the results is seen the stress for laminated composite shells concreted near the pole or near the equator and the bending is localized around the edges.


Article
THERMAL DEGRADATION EFFECT ON THE FRACTURE TOUGHNESS OF GLASS FIBER REINFORCED UNSATURATED POLYESTER RESIN COMPOSITE
تأثير الآتلاف الح ا ررى على متانة التكسير لمت ا ركب البولي أستر الغير مشبع المقوى بالياف الزجاج

Loading...
Loading...
Abstract

Abstract Samples of FRP prepared by applied unsaturated polyester resin as matrix reinforced by one layer woven glass fiber( 0º/90º), using hand lay up method. The prepared samples are subjected to thermal aging at 85 º C for different time in dryer oven up to 1200 hrs time and tested by unnotched sample impact tester to obtained the fracture toughness , polynomial relationshape of order 5 found between Gc and Aging time decreasing Gc strongly to lower value .The Stress strain tests for aged to specific time and without aging samples by tensile test show that sample aged thermally tend to brittle behavior and lost its mechanical properties as aging time increase, while sample without aging show ductile behavior . FTIR analysis show decomposition of the polyester by creating new free radical and observed new peak wave number in transmtion spectra due to fiber crystallization.


Article
THE INFLUENCE OF VARIOUS PARAMETERS ON CREVICE CORROSION OF TWO DIFFERENT TYPE GEOMETRY OF 304L STAINLESS STEEL
تاثير عوامل مختلفة علئ التاكل التصدعي لشكلين مختلفين من الفولاذ المقاوم للصدأ(304L)

Loading...
Loading...
Abstract

ABSTRACT An investigation was carried out to study the effect of various parameters on crevice corrosion of two different type geometry of ( rod, square) 304L stainless steel in 3.4% NaCl solution under static conditions at different temperatures (25, 50) C°, rotation cylinder electrode was used for 100, 200 rpm at the same temperatures. It was found the maximum attack was in square 304L SS at 50 C° under static conditions in account of geometric of specimen whereas slightly effect as the velocity increases due to the passive film is formed on the steel surface. In contrast, the results show the effect of temperature changes and velocity on corrosion rate in rod 304LSS is more pronounced as temperatures and velocities rises enable the migration of chloride ions into the crevice


Article
STUDY ON DEVELOPMENT OF PREPARATION OF AL-ALLOY (8009) AND INHANCING ITS PERFORMANCE BY ADDING ZERCONIUM AND SURFACE TREATMENT
د ا رسة حول تطوير تحضير سبيكة الالمنيوم ( 8009 ) وتحسين كفاءة أدائها باضافة الزركونيوم والمعاملة السطحية. أ

Loading...
Loading...
Abstract

Abstract This work represents an attempt to decrease manufacturing cost and to increase thermal stability and fatigue life of (8009) aluminum base alloy. The alloys were prepared by a single step die casting followed by rapid cooling (instead of the usual five stages forming). A microalloying element (Zr) was added. The study adopted several techniques to improve properties including certain metallurgical variables and mechanical treatments of surfaces. Several tests were carried out to evaluate the performance of alloys, such as thermal stability, and fatigue strength tests before and after surface mechanical treatments (shot peening by ceramic balls), density measurement and metallographic examination.


Article
THE EFFECT OF TEMPERING ON THE FATIGUE BEHAVIOR FOR MEDIUM CARBON STEEL
تأثير الم ا رجعة لفولاذ متوسط الكربون على سلوك الكلال

Loading...
Loading...
Abstract

Abstract This research is concerned with the study of the effect of tempering on the fatigue strength of medium carbon steel (CK 45), by using different heat treatments including quenching in water and oil followed by tempering at (250, 450 & 650) oC comparisons between the effects of two mediums on microstructure, mechanical properties and fatigue strength for each quenching media . The fatigue tests have been done under constant amplitude stresses with a stress ratio (R=-1). The experimental results reveal that water quenching followed by tempering at 250 oC (1 hr) gives maximum fatigue strength for steel, and this is due to the formation of tempered martensite. Long fatigue cracks have been measured and studied from using fractography of fatigue specimens (SEM). Two models have been to proposed to assess fatigue lives of quenched and tempered medium carbon steel at different tempering temperature . The first model was derived from the fatigue crack growth rate equation (da/dN) while the second model was extracted from the stress intensity factor equation (K) .


Article
A STUDY OF MECHANICAL PROPERTIES OF (AL-CU-MG) ALLOYS REINFORCED BY SILICON CARBIDE AND GRAPHITE PARTICULATES
د ا رسة الخواص الميكانيكية لسبيكة (ألمنيوم- نحاس- مغنسيوم) المقواة بدقائق كاربيد السيلكون والك ا رفيت

Loading...
Loading...
Abstract

Abstract This work deals with the preparing of composite materials based on aluminum alloy (2024) and reinforcement materials particles of silicon carbide and graphite powder . Silicon carbide are (3,5,7 wt%) , whereas the proportion of the graphite was certified at (3wt%) . All samples adopted in this work are prepared by stir casting.The results have shown an increasing in mechanical properties such as ultimate tensile strength , Yield strength , Hardness and compressive strength at the expense of ductility for composite material with increasing reinforcement materials content.


Article
EFFECT OF PARTICLES FROM MAGNESIUM OXIDE IN THERMAL INSULATION OF CONBEXTRA EPOXY (EP-10) RESIN
تأثير دقائق من أُوكسيد المغنيسيوم في العزل الح ا رري ل ا رتنج الإيبوكسي كونبكست ا ر (EP-10)

Loading...
Loading...
Abstract

Abstract: Magnesium oxide with (5 μm) particle size with different Weight percentages (5%,15%,25%) was added to conbextra epoxy (EP-10) resin and measured the changing in thermal insulation to this resin . Fourier equation was used to calculate the changing in coefficient of thermal conductivity (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 (0.16 W/m.ºC) after addition (25%) from oxide at temperature (40 ºC) which the best value from oxide additive .

Table of content: volume: issue: