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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: 2016 volume:16 issue:2

Article
OPTIMUM LEVEL DETERMINATION OF DIFFERENTIATED SOFT PAD COMPLIANCE PARAMETERS FOR ROBOTIC LIMBS
إيجاد أفضل مستوى لمتغيرات المطاوعة للوسائد المرنة المفاضلة لأطراف يد الرجل الالي

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Abstract

The most studies of differentiated layer soft pad for robots’ hand fingertips have focused on the relationship between the pad compliance and parameters like compressive load, material and shape of pad. In addition, pressure distribution of contact process should be considere . They did not remark directly the effective set combination of above parameters on the compliance, or studied the weight of each parameter on the process of contact. In this paper, Taguchi method has been used to investigate the optimum set of parameters (compressive load, shape and, material) that give the best flatting of pad. Also the analysis of variance technique (ANOVA) has been employed to compare parameters and predict the contribution of each parameters the compliance. The results explain the effective parameter is the material of soft pad not the shape. In addition, these two methods Taguchi and ANOVA represent good techniques to estimate the effective parameter in the design of robotic hand pad.


Article
EFFECT OF THE EXTERNAL PARALLEL ACOUSTIC EXCITATION ON THE ADVERS PRESSURE GRADIENT (APG)
تأثير الاثارة الخارجية الصوتية الموازية على انحدار الضغط العكسي

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Abstract

There was a needed for a technique to be able to enhance the flow properties by decreasing the velocity in (APG) Adverse Pressure Gradient and increasing the skin friction .The present work used a technique of the effect of external parallel acoustic excitation on the Adverse Pressure Gradient (APG) over a rough surface and smooth surface for a turbulent flow. This study was conducted at fully developed turbulent flow with a Reynolds number based on hydraulic diameter (8.3×104). The experimental ducts test carried out in wind tunnel manufactured from Perspex (250mmx250mm) and length of 690 mm . A Preston tube was used to measure the air flow velocity profile, pressure distribution and skin friction. The adverse pressure gradient was produced in unsymmetrical diffuser with three different diffuser angles (8, 11,and 15) degree. The external excitation was parallel to the flow , and the excitation frequency (150) Hz and SPL (95 ) dB were used in this study . The obtained results showed that the performance, and other flow characteristics of diffusers depend on the angle of diffuser and acoustic excitation, and indicated that the surface roughness enhanced the production of turbulence as well as the turbulence level when compared with the smooth-wall data. It is well known that both wall roughness and APG reduce the mean velocity close to the wall. The rough surface with the external parallel excitation effect are regarded as the key parameters to enhance the flow characteristics, this technique is able to decrease the velocity and increase the skin friction and to enhance the flow properties and thus improve the flow structure.


Article
SUGGESTION RBFNN MODEL FOR THICK COMPOSITE LAMINATED PLATES STRESS ANALYSIS
مقترح لـنموذج RBFNN لتحليل الاجهاد لطبقات الواح المواد المركبة

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Abstract

This work is an attempt to model thick composite laminated plates stress data using radial Basis function neural network architectures. A finite element model with embedded degraded zone in laminated composite plates is developed through training the neural network, because in such case involves many data sets and all of these data are difficult to generate using experiments. Therefore, Training data was performed by using both experimental and finite element program for different dimensions (a, b, h /m) with static and dynamic loads conditions. The neural network model has 6 input nodes representing the load (L) and thick composite size (a=length, b=width and h=thickness), type of lamination, and time. While eighteen nodes at hidden layer and one output node representing the Stress. Dimensions of Plates [a(0.125-0.25)m, b(0.125-0.25)m, h(0.0125-0.025)m], and Static load condition (10) qo(kN/m2), the dynamic load condition (10-100) qo(kN/m2), to(0.05-0.0005sec.) Analytical studies on the performance of the neural network are compared to independent solutions and measured data and found to be in excellent agreement. Verifications are made for both finite element code results and utilization of neural networks without performing too many, long experiments.


Article
INVESTIGATION OF FATIGUE BEHAVIOR USING SURFACE SHOT PEENED TECHNIQUE FOR 2024 – T4 AL-ALLOY
2024-T4دراسة تصرف الكلال باستخدام تقنية القذف بالكريات لسبيكة الالمنيوم

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Abstract

The strength and fatigue lifetime of AL alloy 2024-T4 were estimated using flat fatigue specimen and stress ratio R=-1 at room temperature (RT). After fatigue testing,it was found that both fatigue region (low cycle fatigue and high cycle fatigue) was improved after the shoot penning of the surface .This improvement appeared due to the compressive residual stress established at the shoot penned surface . Also, the fatigue life improvement factor was obtained around (6) while the fatigue strength factor was found to be around 26.


Article
NUMERICAL SOLUTION FOR ADVECTION-DIFFUSION EQUATION USING COLLOCATION BASED NEW RADIAL BASIS FUNCTION
الحل العددي لمعادلة الطاقة باستخدام دالة الأساس الشعاعي المركب

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Abstract

In the present paper, a composite radial basis function was developed by a combination between thin plate and logarithmic radial basis functions. This radial basis function was developed to overcome the singularity appeared when the source and field points coincide. In based new radial function, the thin plate function was used when evaluating diagonal elements of the matrix coefficients and the logarithmic function was used for evaluating the other elements. The advantage of using this new radial basis function represented by overcoming singularity from the diagonal elements when thin plate radialbasis function is used. The new function is a combination of both multiquadric and thin plate radial basis functions. One- and two-dimensional test examples were solved and the present results were compared with the analytical results and gave a good agreement in different applicant in applied mechanics and neural network .


Article
REUSING PULVERISED SOLID WASTES GLASS AS A FILTRATION MEDIUM
اعادة استخدام مسحوق النفايات الصلبة الزجاجية كوسط ترشيح

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Abstract

The aim of this research is to find an economically and environmentally efficient way for reusing industrial solid wastes like glass as substitute for sand media to remove turbidity from aqueous solutions. Three different parameters were used and they are; the gradation with its depth, the filtration rate, and influent turbidity to examine the ability of crushed glass as a filter medium. The glass solid wastes for this study collected from different sources and treated by washing, crushing and sieving according to sizes of sand filter media (as a reference in the evaluation of results). 26 runs were made in pilot filtration unit to achieve these above parameters. Every run time for each media was stopped at ratio of effluent turbidity/ influent turbidity ≥ 0.7. Removal efficiency (or effluents quality) and run time of the glass media were better than that of the sand media where the run time of the filter medium is a function (index) of turbidity removal efficiency. Many of the filtration curves showed that the sand medium had removal efficiency better than glass at the beginning operating and shortly thereafter but with the passage of time the glass filter medium had better removal and longer run time than the sand medium. There was a superiority for glass filings on the sand media with regards to removal efficiency and the run time length, making them a good alternative for sand filter media

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