research centers


Search results: Found 5

Listing 1 - 5 of 5
Sort by

Article
The Effect of Adding Nickel Element on Mechanical and Wear Properties of SiCp-Cu Composites
تأثیر أضافة النیكل على الخصائص المیكانیكیة والبلى للمتراكب ( SiCp-Cu)

Author: Samir B. Younis
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 21 Pages: 6228-6236
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

Reinforced composites are prepared from a Copper as a matrix with SiCpowder in different percentage ( i.e 5-25 vol.%) .For each prepared reinforcedcomposite with respect to SiC addition , they divided into two parts , one undergo toaddition of Ni in fixed percentage (2 wt%) and the other part leave without addition.After drying , mixing and milling process, disc samples were prepared . thesesamples were heat treated at (900°C) using furnace at argon atmosphere. Density,porosity, Vicker microhardness , compressive strength were performed. Dry slidingwear tests of Cu–SiCp composites were carried out using pin on disc apparatus with atypical experimental plan of simultaneous variation of loads (5,10)N . The resultsshow that the density was decreased while porosity increased with SiC content , andthis was less remarkable with nickel presence. Vicker microhardness, compressstrength were improved by the nickel wettability on the reinforcement. Moreoverdecreasing in wear rate comparing with the absence one. The nickel presence modifiesthe interface structural model and is effective in passing load between the matrix andthe reinforcement, by lessening the extent of interfacial debonding.

تم تحضیر المتراكب المكون من النحاس كمادة أساس ودقائق من كاربید السلیكون كمادة تدعیم بنس ب م زج25 % وزناّ) , حبث حضرت مجموعتین من النسب أعلاه , الاولى تم أضافة عنصر النیكل الیھا بنسبة - مختلفة ( 5ثابنة ( 2% وزناّ) , والاخرى بقت كما ھي. وبع د عملی ة النجفی ف والخل ط ت م ك بس النس ب المحض رة غل ى ش كل900° ) وفي جو من الاركون . تم فحص الكثاف ة والمس امیة والص لادة ومقاوم ة C) أقراص تم تلبیدھا عند درجة5,10 ) . م ن النت ائج N) الانضغاط للعینات المحضرة, اضافة الى فحص البلى , حیث تم اس تخدام أحم ال مختلف ةالمستحصلة , تبین ان الكثافة تقل بازدیاد النسب الوزنیة لكاربید السلیكون تقابلھا زیادة ف ي نس بة المس امیة . لك نھذا العامل كان أقل تأثیراّ في العینات التي تحتویعلى عنصر النیكل . اضافة الى ذلك ان تلك الاض افة ف د حس نتمن الخصائص المیكانیكیة للمتراكب من صلادة ومقاومة انضغاط . علاوة على ذلك ص غر مع دل البل ى مقارن ةمع العینات التي یختفي فیھا عنصر النبكل , حیث ان وجوده یؤدي الى توزیع الحمل الموضوع بین مادة الاساسومادة التدعیم وبالتالي تفادي الانفصال الحادث في السطح البیني


Article
Studying Properties of Cu-Al-SiC Composites Prepared by P/M Technique
دراسة خصائص المتراكب (Cu-Al-SiC) الملبد متالورجيا المساحيق

Authors: Ziyad S. Ahmed --- Ali M. Mousa --- Samir B. Younis
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 7 Pages: 1240-1248
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

A composite of copper powder reinforced with SiCp (0-10 wt%) in whichaluminum powder of ( 2 wt%) was added for improving wettability of the ceramie phase. . The composite mixture was prepared by mixing with a ball mill for one hour to ensure a homogenous distribution on the composite .Gteen compacts pressed at (350MPa) a steel mold of (12mm)diameter were then sintered at (900 °C) for two hours in an electric furnace, in argon atmosphere . Optical microscopy, Density, porosity content and Vicker's hardness test were then conducted for the sintered samples. Obviously, it was concluded that there was enhancement of the physical and mechanical (hardness) properties of the sintered compacts with increasing the SiC content.

حضرت عينات متراكبة من مسحوق النحاس كمادة اساس ودقائق كاربيد السليكون بنسبة % %10 وزنا) كمواد تدعيم، اما مسحوق الالمنيوم فقد تمت اضافته الى المزيج بنسبة ثابتة 2 -0) وزنا وذلك لزيادة الترطيب السطحي. تم خلط المزيج بواسطة طاحونة كرات كهربائية دوارة لمدة (350MPa) ساعة للحصول على مسحوق متجانس. تم بعدها كبس العينات تحت ضغط يعادل 12 ، ثم لبدت في درجة حرارة mm بواسطة مكبس هيدروليكي في قالب فولاذي بقطر يساوي 9000 ) لمدة ساعتين في جو من غاز الاركون. ثم فحصالعينات المستحصلة باستخدام المجهر C) من خلال .( HVS- الضوئي وقياس الكثافة والمسامية والصلادة للعينات بواسطة جهاز( 1000النتائج المستحصلة ظهر بأن اضافة كاربيد السليكون الى النحاس قد عزز من خواصه الفيزيائية والمكيانيكية.


Article
Influence of Geogrid Reinforced Loose Sand In Transfer of Dynamic Loading To Underground Structure

Authors: Mohammed Y. Fattah --- Nahla M. Salim --- Mohammad S. Ismaiel
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 11 Part (A) Engineering Pages: 1915-1927
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

Underground facilities are an integral part of the infrastructure of modern society and are used for a wide range of applications, including subways and railways, highways, material storage, and sewage and water transport. Underground facilities built in areas subject to dynamic activity must withstand both dynamic and static loading. This study focuses on the effect of the geogrid reinforcement in transfer of the dynamic load to the underground structure. The underground structure was simulated as a PVC pipe 110 mm in diameter inside the sandy soil. In order to investigate the response of soil, footing and underground tunnel to dynamic loading, a physical model was manufactured. The manufactured physical model could be used to simulate the application of dynamic loading. The total number of the tests carried out is 4 models. All the 4 model tests with relative density equal to 40% corresponding to loose sand. The applied harmonic load has an amplitude of 0.5 ton and a frequency of 2 Hz. For each amplitude and frequency of the load, the sand models were tested without geogrid and with geogrid of three series of geogrid depths from the model surface (0.5B, 1B and 1.5B) and width equal to (1B), where B is the strip footing width. The dynamic load was applied in the tests by a hydraulic jack system. The response of the tunnel to dynamic loading includes measuring the pressure above the crown of the tunnel by using a pressure cell (manufactured by Geokon company) as well as measuring the amplitude of displacement by using a vibration meter. The response of footing was elaborated by measuring the total settlement using sensors in the dynamic load apparatus. It was found the pressure above the crown of the tunnel decreased by about (14-33) % when using geogrid reinforcement. Also, it was found the settlement decreased by about (13-20) % when using geogrid reinforcement.

Keywords

Tunnel --- dynamic load --- geogrid --- load transfer


Article
Dynamic Finite Element Analysis of Sandy Soil-Pipe System Reinforced by Geogrid

Author: N.H. Jajjawi
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 4 Part (A) Engineering Pages: 421-430
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The stability of tunnels and other underground structures under the influence of dynamic load is one of the important issues that should be studied carefully. The objective of the present paper is to study the effect of the geogrid reinforcement in transfer of the dynamic load to the underground structure. The underground structure was simulated as a plastic pipe within the soil. The investigation focuses on the influence of parameters such as load amplitude, depth of geogrid layer and width of geogrid layer using the finite element method by QUAKE/W computer program for the analysis. It was concluded that when the geogrid reinforcement width equals (1B), the total stress on the crown of pipe decreases by about (17%) compared with unreinforced soil, but this percentage decreases to (10%) when the geogrid width equals to (2B). The percent vertical settlement on the pipe crown decreases by about (35%) when using reinforcement of width equals (2B) compared with test results unreinforced soil, while when the width equals (1B), the percent vertical settlement decreases to about (15%), this indicates that when the width of reinforced soil increases, the vertical settlement decreases.


Article
NUMERICAL STUDY OF DOWELED EXPANSION JOINTS ON PLAIN CONCRETE PAVEMENT SYSTEM

Authors: Zainab Ahmed Al-kaissi --- Mohammed Hashim Mohammed Nabaa Sattar Kareem
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 6 Pages: 58-71
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

In this paper, the ABAQUS / CAE 6.13.1 program is used to study the effect of several variables on the efficiency of the load transfer through an expansion joint in plain concrete pavement system under the influence of the static wheel load. The variables that have been addressed are the diameter of dowel bar (12, 16 and 20 mm), subgrade soil type (A-6) and (A-7-5), concrete type (normal strength concrete and high strength concrete), joint width (10, 20 and 30 mm), thickness of the concrete slab (125, 175 and 250 mm), position of static wheel load (corner load, internal load and edge load) and the effect of soil damage. The results showed, the load transfer efficiency (LTE) and joint effectiveness (E) are enhanced from 69.82% to 89.73% and from 82.23% to 94.59%, respectively as dowel diameter increases from 12 mm to 20 mm, from 60.48% to 79.64% and from 75.37% to 88.66, respectively as joint width decreases from 30 mm to 10 mm, from 64.24% to 89.73% and from 78.23% to 94.59%, respectively as slab thickness decreases from 250 mm to 125 mm and from 69.81% to 79.64% and 82.22% to 88.66%, respectively when CBR value of subgrade soil increases from 5% to 7%, while approximately the same LTE (about 80%) and E (about 89%) are resulted as the concrete compressive strength increases from 27 MPa to 43 MPa. Corner load reduces LTE and E from 84% to 70.49% and from 91.3 to 82.7, respectively as compared to internal load. Presence of weak or gap in subgrade soil reduces LTE and E from about 79% to 59% and 88% to 74%, respectively.

Listing 1 - 5 of 5
Sort by
Narrow your search

Resource type

article (5)


Language

English (5)


Year
From To Submit

2018 (1)

2017 (1)

2016 (1)

2012 (1)

2010 (1)