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Article
Impact Response for Two Designs of Athletic Prosthetic Feet
استجابه الصدمه لتصميمين من الاقدام الاصطناعية الرياضيه

Authors: Mohsin N. Hamzah محسن نوري حمزه --- Ammar S. Merza عمار سليم حميد --- Lamees Hussein Ali لميس حسين علي
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2018 Volume: 24 Issue: 3 Pages: 13-28
Publisher: Baghdad University جامعة بغداد

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Abstract

The present work evaluated the differences in mechanical properties of two athletic prosthetic feet samples when subjected to impact while running. Two feet samples designated as design A and B were manufactured using layers of different orientations of woven glass fiber reinforced with unsaturated polyester resin as bonding epoxy. The samples’ layers were fabricated with hand lay-up method. A theoretical study was carried out to calculate the mechanical properties of the composite material used in feet manufacturing, then experimental load-deflection test was applied at 0 degree position and 25 degree dorsiflexion feet position and impact test were applied for both feet designs to observe the behavior of the feet under static and impact loading and compare properties like stiffness, efficiency, rigidity, and shock absorption at different drop angles range from 25 degrees to 60 degrees which perform the foot positions while running. The load-deflection test result shows that the maximum deflection of the proposed design B was 32.2 mm at 0 and 38.45mm at 25. While it was 41mm at 0˚ and 39mm at 25˚ for design A. Impact test result shows that design B foot gives peak load of 128 .7 kg with a peak time of 0.06 sec, while design Afoot gives 125.32 kg peak load with a time of 0.069 sec.

يقيم البحث الحالي الاختلافات في الخواص الميكانيكية لعينتين من الاقدام الاصطناعية عند التعرض للصدمه أثناء العدو.حيث في هذا العمل، تم تصنيع عينتين اشير اليها ب AوB باستخدام طبقات من الألياف الزجاجية المنسوجه بأتجاهات مختلفه والتي تم ربطها مع بعضها باستخدام راتنجات البوليستر غير المشبعة باستخدام طريقه الترتيب اليدوي لطبقات الالياف.ثم أجريت دراسة نظرية لحساب الخواص الميكانيكية للمواد المركبة المستخدمة في تصنيع الأقدام، و تم تطبيق عده اختبارات تجريبيه منها اختبارالحمل-الانحراف عند وضع القدم بزاويه 0 و 25 درجة واختبار صدمه على كلا العينتين لمراقبة سلوك القدمين تحت تأثير الحمل الثابت وحمل الصدمه ومقارنه خضائص كالصلابه والكفاءه والصلاده وقابليه امتصاص الصدمة عند زوايا سقوط مختلفه تتراوح من 25 درجه الى 60 درجه والتي تمثل مواقع القدم اثناء دوره العدو.من نتائج اختبار الحمل-الانحراف تبين ان اقصى انحراف لعينه القدم B كان 32.2 ملم عند زاويه 0 و 38.45 ملم عند زاويه 25 في حين كان 41 ملم عند زاويه 0 و39 ملم عند زاويه 25 لعينه القدم A. نتائج اختبار الصدمه اظهرت ان عينه القدم B تعطي حمل ذروه يعادل128.7 كغم خلال 0.06 ثانيه في حين عينه القدم A تعطي 125.32كغم حمل ذروه خلال 0.069 ثانيه.الكلمات الرئيسه: قدم اصطناعيه رياضيه ;مواد مركبه ,اختبار صدمه .


Article
Impact Strength for the 3D Textiles Fiber Reinforced Cementitious Composites Plates
تحمل الصدمة للصفائح السمنتية المركبة والمسلحة بنسيج زجاجي ثلاثي الابعاد

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Abstract

The use of textile reinforcement made from non-corrosive materials, such as carbon and glass can reduce the required concrete material; this is known as Textile Reinforced Concrete (TRC). This study deals with plate specimens having dimension of 500×500×40mm tested under impact load at 28 and 90 days age under two conditions of ends, simply supported and fixed. Cement mortar with about 60 MPa, 7cm cube compressive strength at 28 days was designed for casting the plates. Plate specimens were divided into four groups, they consist of reference plates (no reinforcement) and plates reinforced with 3D glass fabric having three different thicknesses 6, 10 and 15mm.The results indicate that using 3D textile glass fabric cause an increase in number of blows, reduce in final stage deflection, an improvement in toughness and energy absorption under impact loads. Using 3D textile glass fiber with 10mm thickness gave higher number of blows for 28 and 90 days as compared with 6 and 15 mm. Plates with slice 6mm 3D textile glass fiber in two way reinforced has significantly enhancement in number of blows, the improvement was about (80 - 125%) and (128.5- 114. 3%) for 28 and 90 days respectively. The specimens showed increase in the energy absorption, besides the number and width of cracks was reduced and only few cracks are propagated up to the edge of the plates.

ان استخدام الالياف اوالنسيج بابعاد ثلاثية مصنوعة من مواد زجاجية اوكاربونية ذات طبيعة كيميائية خاملة يؤدي الى تقليل بكمية المواد السمنتية الداخلة بالخلطة الخرسانية. حيث تضمنت هذه الدراسة قياس تحمل الصدمة لصفائح بابعاد 500*500*40 ملم وبعمر 28 و90 يوم بواقع نوعين من الشروط الحدودية (بسيطة وثابتة). وتم صب الصفائح باستخدام مونة اسمنتية ذات مقاومة انضغاط 60 ميكاباسكال بعمر 28 يوم. قسمت الصفائح الى اربع مجاميع مؤلفة من صفائح بدون استخدام اي الياف لغرض المقارنة وصفائح مسلحة بثلاث اسماك مختلفة (6و10و15ملم) من الياف زجاجية ثلاثية الابعاد. فحصت الصفائح تحت تاثير حمل الصدمة واظهرت النتائج ان استخدام نسيج زجاجي ثلاثي الابعاد ادى الى تحسن في خواص الصفائح وذلك بزيادة عدد الضربات وتقليل الانحرافات وزيادة في مقدار الطاقة الممتصة. ان استخدام الياف زجاجية بسمك 10 ملم تطلب زيادة في عدد الضربات المطلوبة للفشل بعمر فحص 28 و90 يوم مقارنة مع سمك 6 و15 ملم. كما ان استخدام نسيج ثلاثي الابعاد على شكل شراح بطبقتين وبسمك 6 ملم ابدى قوى ربط اكبر وتحسن بعدد الضربات ، حيث كان التحسن بمقدار 80-128 % و128.5-114.3% لاعمار 28 و90 يوم اضافة الى ان جميع الصفائح اظهرت زيادة في امتصاص الطاقة ونقصان في سمك وعدد الشقوق خلال الفحص .


Article
Experimental Study of Mechanical Properties of Type Linear Low Density Polyethylene and Mold Design

Authors: Samir A. Amin --- Ali Y. Hassan
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 5 Part (A) Engineering Pages: 493-499
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In general, the manufacture of plastic materials is commonly in the world due to their applications. Plastic is light weight, cheap, and able to be used in different industries, for example parts of automotive and home tools. This research represents a challenge on how to design and manufacture a changeable mold. First, a mold was designed by the Auto CAD program and then manufactured in the workshop. The mold consists of three parts, the middle part has changeable cavity. The mold was cooled by worm net pipes embedded into the third part. All specimens were manufacture in this mold. The injection plastic flow is perpendicular on mold. The goals of this research are to design and manufacture a mold and to determine the mechanical properties of linear low density polyethylene. Three types of test were executed, tensile, impact and bending. The results of tensile test showed that the tensile strength value is 15 MPa, Young’s modulus is 0.18 GPa, yield stress is 12 MPa, and Elongation to break is 70.88 mm. From impact test, the impact strength is about 193.75 KJ/m2, while in bending test, the flexural strength is about 18 N/mm2 and the shear stress is 1.5 N /mm2.


Article
The Influence of Immersion in Different Chemical Solutions on the Mechanical and Physical properties of (Epoxy/Styrene-Butadiene Rubber) Blend Reinforced with Nano Copper Oxide

Author: Rana M. Salih
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 2 Part (B) Engineering Pages: 104-109
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The aim of this work was to evaluate some mechanical and physicalproperties of a composite material which consists of (epoxy/styrene-butadienerubber) blend as a matrix, reinforced with copper oxide (CuO) with a weightfraction 3%, and the composite material was manufactured by hand lay-up.The optimum mixing ratio was (75:25) % of epoxy and (SBR) was chosen toaccomplish the work due to its highest impact strength (2.1KJ/m2). The teststhat were performed on the material were: tensile test, impact test, thermalconductivity test, and the absorption test, in addition to the microscopicimaging using scanning electron microscope (SEM), to determine the surfacemorphology of the specimens. Sodium hydroxide (NaOH) and hydrochloricacid (HCl), both (0.1) normal concentration solutions, were used for theimmersion. The results showed that CuO nanofiller improved tensile andimpact properties of the blend, besides increasing resistance to diffusion ofchemicals into the material. The results showed that the immersion in HClsolution increased the impact strength of the composite from (2.27KJ/m2) to(3.38KJ/m2), and also increased the tensile strength from (9.2MPa) to (9.8MPa), while immersion in NaOH solution decreased the tensile strength to(7.3MPa), but increased the impact strength to (2.42KJ/m2). Thermalconductivity was (0.21W/m.°C) before immersion in solutions, but changed to(0.27W/m.°C) and (0.24W/m.°C) after immersion in HCl and NaOHrespectively. The weight gain after immersion in NaOH was higher than weightgain after immersion in HCl.

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