Iraqi journal of mechanical and material engineering

A Nissan pickup car shown in Fig.1 is widely used car in Iraq. In spite of its being sturdy, this car has a problem regarding to failure of their suspending ball joints. Nowadays , it is seen the ball joint of this car fails suddenly without any sign of consumption and this case is a dangerous as well as disturbing factor for traffic and driver. So there should be something else supports car when the ball-joint fails. This research has a modification of this ball joint for this purpose. The modification has depended on the results obtained from the numerical analysis of the loaded ball-joint in two situations (forms), the first situation (form) when its angle is negligible and second situation (form) when this angle is considerable. Measurements of parts of ball joint of Nissan pickup car have been made and these parts have been drawn in two forms (situations) by using CATIA software. Also, Measurements of parts’ lengths of suspension system of Nissan pickup car has been made and an approach model of its suspension system has been created by using MSC ADAMS software to view the angle of ball-joint with Max.travel of suspension system., all drawn forms have been imported to ANSYS WORKBENCH software where a three- dimensional model was created and maximum load is applied to ball-joint Then, solution had been done and the results were obtained. Then, a modification is created and drawn by CATIA software, after that it is imported to ANSYS WORKBENCH software to check it ability for supporting the results

This article describes some mechanical properties of alumina-filled epoxy composites. In this work, the epoxy matrix was reinforced with increasing amount of alumina particles in the range of 0-40% by weight with different particle size (d≤8, 18≤d≤25, 33≤d≤45, 50≤d≤62)µm. From the flexural test results, it was observed that the flexural modulus increases with increasing α-alumina content from 10 to 40 wt%. At the same time, the results indicated that there are no much effect on the flexural modulus with change the particle size in the range of (d≤8, 18≤d≤25)µm. The highest value of flexural modulus was recorded with 40 wt% of α-alumina content and (d≤8)µm particle size. It was also found that the 40 wt% alumina content and (d≤8)µm particle size recorded the highest value of fracture toughness (Gc), fracture toughness (Kc), hardness (HB), and wear resistance which were improved by (253%, 282%, 230%, and 82%), respectively. Also, in this work a mathematical modeling is implemented and regression equations are obtained by using ( SPSS ) software to predict the properties of alumina filled epoxy composites. Comparing the predicted and measured values gives high prediction accuracy. The accuracy of prediction has been (90.13%, 85.95%, 90.28%, 89.76%, and 84.36%) for flexural modulus, toughness, fracture toughness, hardness, and wear rate respectively.

Laminar mixed convection for incompressible flow in two sided non-facing lid driven square cavities are numerically investigated in this study using ANSYS 12.1 commercial software. Depending on the movement direction for the walls and various temperature locations on these walls, cases have been considered. Vortices are generated by moving the upper and the right walls in the first case, while in the second case, bottom and left walls are using with different locations for hot and cold temperatures on the moving walls. For each case, the non-facing walls that which in opposite side to the moving walls are thermally insulated and stationary. Natural and forced convections are distinguished by an important relative value of Richardson number (Ri=Gr/Re2) which relates the fluid flow and the heat transfer in the cavity. Governing parameters are varied as 0.1 < Ri < 10 and Pr=0.7. The obtained results show that the fluid flow and heat transfer in the cavity are effected by Richardson numbers, locations and directions of moving walls, and locations of hot and cold temperatures. Two sided non-facing lid driven for the cavity is give the same results for streamlines and isotherms with the another opposite two sided non-facing lid-driven, but inversely and upside down for different Richardson numbers. The results of this investigation illustrate that when install the hot temperature on the lower moving wall and the cold temperature on the left moving wall in the second case, the local Nusselt number in this situation is to be relatively higher and heat transfer is enhance, as compared with the other differential heated cavities orientations.

This research is devoted to study the effect of shot peening time with steel balls on mechanical properties of AA2024-T4 alloy. The test carried out using standard tensile specimens under various peening times (5, 10 , 15 , 20 and 30 minutes). Results showed an increase in yield and tensile strength values with increasing peening time up to 15 minutes where they were 355 & 505 MPa respectively. Also the strain hardening factor (n =0.26) and strength factor (k = 910 MPa) were maximum at this period of peening .On the other hand the maximum percentage of elongation was 22.7% obtained at 30 minute peening time .

This investigation is aimed at understanding the role of adding ceramic inclusion, alumina (Al2O3) on the densification, microstructure and mechanical properties of cemented carbide cutting inserts. The samples were prepared of an initial mixture of 62 WC, 32 (Ti-W) C and 6Co wt% particulates; different additions of Al2O3 of 1, 2, 3, 4, 5 and 7 wt% were introduced to that mixture. The testing specimens were compacted via powder metallurgy at 200 MPa and sintered at 1410°C under vacuum. The green and sintered densities have decreased; the figures of macrohardness, Vickers hardness and transverse rupture strength have also deteriorated with the increase of alumina content. The macrohardness has almost declined of 30% at 3% alumina. This is ascribed to the interfacial grain-boundary decohesion between Al2O3 and carbide particles as can be observed from scanning electron microscopy images which depicts the monolithic clusters in the final consolidation of the compacts.

This research deals with the study of the effect of temperature on the rheological properties (yield point, plastic viscosity and apparent viscosity) of invert emulsions. Twenty seven emulsion samples were prepared; all emulsions in this investigation are invert emulsions when water droplets are dispersed in diesel oil, the resulting emulsion is called water-in-oil emulsion (W/O). The rheological properties of these emulsions were investigated using a couett coaxial cylinder rotational viscometer (Fann-VG model 35 A), by measuring shear stress versus shear rate at different three temperatures (77, 122, and 167) F°. By using the Solver Add in Microsoft Excel®, the Bingham plastic model was found to be the best fits the experimental results. It was found that when temperature increased, it causes a decrease in the rheological properties (yield point, plastic viscosity and apparent viscosity) of emulsions which is due to the change in the viscosity of continuous phase of emulsion that is diesel oil.

In this paper, propose an optimal control design for variable speed wind turbine subject to disturbance wind and white noise. The dynamic modeling of the wind turbine and its linearization are derived, and its performance has been established using MATLAB environment.This method includes a description and some discussion of the Kalman state estimator, and application, particularly in the area of wind turbine system, to control the angular speed based on LQG (Linear Quadratic Gaussian). The simulation results show, the proposed LQG controller of the system gives good response and have excellent performance when compare with LQR (Linear Quadratic Regulator) controller

The anatase phase of titania has great potential to be used in various applications. Thus; the synthesis of phase-pure nanocrystalline anatase has attained great importance in the past decade. In the present work, the sol-gel method was used to prepare such nanoparticles. It has been found that the sol-gel method can, with the help of long aging time, produce phase-pure anatase nanoparticles that have polygonal shape with edges’ length in the range of (~30-70nm). The firing temperature should be kept higher than 500°C to get fully crystalline nanoparticles and lower than 800°C to avoid the phase transformation to rutile phase

The study investigates effect of salt ratio on the thermal stress and strain concentration in composite exhaust tube model. The study builds three-dimensional model of exhaust tube and analyses it numerically with finite element method using ANSYS Software. The investigation depends on the experimental results of tensile test and thermal conductivity test to determine the mechanical and thermal properties of composite specimens. The composite specimens were immersed in the salt environment of different concentration ratios (15%, 35%, and 55%) for forty days. The numerical results show that the thermal stresses (σx, σy and σz) at node number (2873) increases by ratio of (58.2%) while the thermal shear stress (τxy) at node number (20600) increases by approximate ratio of (56.17%) as a result of increase in the salt concentration ratio from (15%) to (55%). The maximum thermal shear strain (gxy) increases with ratio of (21.8%) due to increase in the salt concentration ratio from (15%) to (55%). The maximum thermal stresses and strains concentrate at the end of composite exhaust tube model as a result of expansion which happened in the tube model. The temperature distribution and heat transition with time is described in three dimensional composite exhaust tube model. The theoretical and numerical results are compared, and the disparity between them is equal to (9%).

Experimental and numerical studiesare investigated to study the two-phase flow phenomena around a circular cylinder in a rectangular enlarging channel which has the dimensions (10 ´ 3 ´ 70 cm) enlarged from assembly circular tube of the two phases. Experiments are carried out inthe channel with air-water flow with different air and water flow rates. These experiments are aimed to visualize the two phase flow phenomena as well as to study the effect of pressure difference through the channel with the cylinder. All sets of the experimental data in this study are obtained by using a pressure transducer and visualized by a video camera for different water discharges (20, 25, 35 and 45 l/min) and different air discharges (10, 20, 30 and 40 l/min). Whilethe numerical simulation is conducted by using commercial Fluent CFD software to investigate the steady and unsteadyturbulent two dimensional flows for different air and water velocities with smooth enlargement. The results showed that the when air discharge increases, high turbulence is appear which generate more bubbles and waves

In this work, simple ceramic-metal functionally graded materials with three different layers has been prepared and tested. Ceramic and metal materials were represented by alumina and aluminum respectively. Powder technology practices were used extensively in preparing each of four set of FGMs samples. All samples have the same chemical composition. Two variables were studied, compacting load and sintering temperature. All samples were imparting graded hardness reading across the thickness. The values of hardness readings are increased according to the hardest constituent’s increment (i.e. Alumina) at constant sintering temperature and compacting load. Compaction load increment as well as sintering temperature imparts another reasons for improvement in hardness properties. Microscopic observations show an interesting features of the layers microstructure where composed from an aluminum and alumina particles and show good adhesive between alumina particles and Aluminum while Aluminum surrounded alumina particles from all studies due to good mixing practice during preparation stage.

Aluminum alloys (6XXX series) are widely used in the structural components of automotive and construction industries as they show a good combination of formability, corrosion resistance, weldability, and final mechanical properties. The objective of this work was to introduce improve properties of 6061-T6 aluminum alloys such as impact energy, thermal age hardening behavior, thermal stability and corrosion resistance in 3.5%NaCl solution by using quenching in 35% polyethylene glycol and addition alloying elements, i.e. Zr with Ag together to this alloy. And to determine the effects of artificial ageing on the properties. The precipitation hardening usually undergoes a thermal treatments, which consists of a solution heat treatment (530ºC for 1 hour) this temperature was selected among three temperatures that used to solid solution treatment, quenching (in water, in 35% PAG polymer solution) and artificial ageing. The experimental study is focused on artificial ageing upon that the temperatures is varying from 160ºC - 180ºC - 200ºC at different periods of time. Several tests were carried out to evaluate the performance of alloys before and after ageing, such as Vickers hardness, impact, thermal stability(DSC), metallographic examination, corrosion resistance in 3.5%NaCl solution and X-Ray diffraction (XRD).Results showed that the hardness of the base alloy(A) as homogenized was 48.7(kg/ ) whereas to alloy with additions from (Zr and Ag)(B) alloy was 50.7,the hardness at solid solution treatment was in alloy that quenched in water higher than these quenched in polymerAddition of 0.03% Zr with 0.18% Ag to the base alloy improves thermal age hardening behavior by (17.3%) when quenching in water, and by (17.1%) when quenching in 35%PAG at ageing temperature 180 in comparison to the base alloy.The addition of 0.03% Zr with 0.18% Ag together to base alloy improves impact energy by (25%) when quenching in 35%PAG corresponding to the base alloy when aging at 180 ºCFrom DSC curves could conclude the alloys that quenched in polymer solution have been higher thermal stability than these quenched in water.An improvement of corrosion resistance in 3.5% NaCl solution when the alloys quenched in polymer solution have been higher corrosion resistance than these quenched in water at aging temperature 180ºC.

In this investigation, the composite material was prepared which was consist of polyester as the matrix and B4C as additive material with grain size equal to25μm with different weight fractions (10%,20%,30%,40%,50%). This investigation was done into two stages: the first stage is to produce the composite material, while the second stage is to test the new material which includes tensile test, hardness and microstructure evaluation. Also photomicrographs were taken by ordinary microscope. The results showed that obviously improvement in properties of the new composite material especially at weight fraction of (40% , 50%).