Mohammad Azadi
Assistant Professor, Department of Mechanical Engineering, University of Semnan, Semnan, Iran
[ 1 ] - Failure Mechanisms Investigation in Thermal Barrier Coatings under Isothermal and Non-sothermal Fatigue Loadings using Design of Experiments
In this article, failure and fracture mechanisms in an aluminum alloy (which has been used in diesel internal combustion engines), with and without ceramic thermal barrier coatings, have been investigated under isothermal and non-isothermal fatigue loadings. In this research, the base material is an aluminum-silicon-magnesium alloy and the thermal barrier coating includes a metallic bond coat l...
[ 2 ] - A new low cycle fatigue lifetime prediction model for magnesium alloy based on modified plastic strain energy approach
Nowadays, the technology intends to use materials such as magnesium alloys due to their high strength to weight ratio in engine components. As usual, engine cylinder heads and blocks has made of various types of cast irons and aluminum alloys. However, magnesium alloys has physical and mechanical properties near to aluminum alloys and reduce the weight up to 40 percents. In this article, a new ...
[ 3 ] - Nonlinear Finite Element Analysis of Thermoelastic Stresses of FGM Rotating Disk Considering Temperature-Dependency of Material Properties
In the present paper, nonlinear radial and hoop thermoelastic stresses analysis of a disk made of FGMs material is investigated. According to this purpose, finite element method is used. In the present method, second-order one-dimensional element (with three node points) is proposed. The geometrical and stress boundary conditions are defined in the state of non-existence of external pressure an...
[ 4 ] - تأثیر عملیات حرارتی بر ریز ساختار، خواص مکانیکی، رفتار شکست در همبسته آلومینیوم- سیلیسیوم- مس بستار
در این مقاله تغییرات ریز ساختار و خواص مکانیکی (سختی و استحکام کششی) آلیاژ آلومینیوم- سیلیسیوم- مس (آلیاژ A380، مورد استفاده در سرسیلندر موتور) در اثر عملیات حرارتی T4 و T6 مورد ارزیابی و مقایسه قرار گرفت. به این منظور آنیل انحلالی در دمای 490 درجه سانتیگراد به مدت 5 ساعت انجام شد. عملیات حرارتی پیرسازی T6، در دماهای 180، 200، 220 و 240 درجه سانتیگراد به مدت 1، 3، 5 و 7 ساعت انجام شد. در نهایت...
[ 5 ] - مدلسازی رفتار خزشی در آلیاژ آلومینیوم- سیلیسیوم- مس- نیکل- منیزیم در دماها و سطوح تنشی مختلف
در این مقاله، رفتار خزشی آلیاژ آلومینیوم- سیلیسیوم- مس- نیکل- منیزیم، که در ساخت قطعه پیستون در موتور خودرو کاربرد دارد، در دماها و تنش‌های مختلف، مدلسازی شد. برای این منظور، آزمون خزش بر روی نمونه‌های استاندارد ریخته‌گری شده، تحت نیروی کشش ثابت و دمای ثابت، اجرا گردید. دماها در آزمون خزش برابر با 250، 275 و 300 درجه سانتیگراد و سطوح تنشی نیز، برابر با 75، 100 و 125 مگاپاسکال در نظر گرفته شد. ...
[ 6 ] - Corrosion Failure Study in an Oil Cooler Heat Exchanger in Marine Diesel Engine
In this article, the failure of a heat exchanger during its operation in the marine environment has been analyzed. This heat exchanger was used for cooling the oil in a marine diesel engine. Based on the existing failure history, damages in engine components were observed after 89 hours of engine working due to the leakage of the sea water to the oil. For the objective of the failure analysis, ...
[ 7 ] - Temperature Effect on Creep and Fracture Behaviors of Nano-SiO2-composite and AlSi12Cu3Ni2MgFe Aluminum Alloy
In the presented article, the temperature effect was studied on creep properties and fracture behaviors of AlSi12Cu3Ni2MgFe aluminum-silicon alloys, unreinforced and reinforced with SiO2 nano-particles. For such objective, standard specimens were fabricated by gravity casting and stir-casting methods, for aluminum alloys and nano-composites, respectively. Then, force-controlled creep...
[ 8 ] - Ratcheting crystal plasticity modeling in microstructure of magnesium alloy under stress-controlled cyclic tensile loading with non-zero mean stress
Todays, the requirement of lowering the vehicle weight for the reduction of the fuel consumption and emissions, one of the methods considered by designers is to use the ligh magnesium alloy under cylclic loadings. In this article, considering the microstructure of the AZ91D magnesium alloy, its crystalline structure, a model for predicting the ratcheting behavior of this alloy was adapted and v...
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