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Open Access Article
1 - Behavior Analysis of Cold Expanded-Bolt Clamped AL2024-T3 Plate
M. Sayah Badkhor A. R. Naddaf Oskouei* H. Mohammadi Hooyeh F. Shirbakht -
Open Access Article
2 - Investigation of the Effect of V-Clamp Band Design Parameters on the Bending and Axial Stiffness of the Flanged Joints
SeyyedAbdolSajjad Borhani AliAkbar Lotfi neyestanak Ali davar -
Open Access Article
3 - A New Model of Pull-in Voltage for MEMS Variable Capacitive with Fully-clamped Diaphragm
Bahram Azizollah Ganji Sara Gholinezhad Shafagh -
Open Access Article
4 - Designing and Simulating of Step-Up DC-DC Converter for Fuel Cell Electric Vehicles
Maher Abdulnabi Alwan Ghazanfar ShahgholianStep-Up DC-DC Converters are widely used in electric vehicles, because the use of batteries and fuel cells increases the voltage level to drive the electric motor. One of the problems of step-up converters is the increase in volume and weight due to step-up transformers MoreStep-Up DC-DC Converters are widely used in electric vehicles, because the use of batteries and fuel cells increases the voltage level to drive the electric motor. One of the problems of step-up converters is the increase in volume and weight due to step-up transformers. So far, various methods, such as switched capacitor, coupled inductor and multiplier circuits, have been used to eliminate the transformer and reduce the volume and weight of the circuit. To further reduce the volume and weight of the circuit, it is necessary to increase the switching frequency, which is possible only by using the soft switching method. Using an auxiliary switch to create soft switching conditions is common in most methods, because not using an auxiliary switch imposes voltage and current stress on the circuit. In this article, a step-up converter with an auxiliary circuit of zero voltage transition (ZVT) is presented, which provides switching conditions at zero voltage to turn on the switch and switching at zero voltage to turn off the switch. The voltage stress of the converter is very low, and all the diodes are switched off at zero current, so they do not have reverse recovery problems. Also, in addition to absorbing the energy of the leakage inductor, the clamp capacitor helps to increase the gain of the converter. The provided converter is simulated in P-Spice software. To check the performance of the converter, a laboratory model with a power of 150 watts has been designed and tested. Manuscript profile -
Open Access Article
5 - Evaluation of Fatigue Life Reduction Factors at Bolt Hole in Double Lap Bolted Joints Using Volumetric Method
F Esmaeili S Barzegar H Jafarzadeh -
Open Access Article
6 - Investigation on the Effect of Tigthening Torque on the Stress Distribution in Double Lap Simple Bolted and Hybrid (Bolted -Bonded) Joints
F Esmaeili T.N Chakherlou -
Open Access Article
7 - Temperature-dependent Vibration Analysis of Clamped-free Sandwich Beams with Porous FG Core
Mohsen Rahmani -
Open Access Article
8 - A New Soft Switching Interleaved Flyback Converter with Recovery Leakage Inductance Energy
Zahra Peiravan Majid Delshad Mohammadreza AminiIn this paper, a ZVS interleaved flyback converter with two transformers is presented, which consists of two active clamp flyback converters and the main switch of one converter acts as an auxiliary switch of another converter. This converter has less auxiliary elements MoreIn this paper, a ZVS interleaved flyback converter with two transformers is presented, which consists of two active clamp flyback converters and the main switch of one converter acts as an auxiliary switch of another converter. This converter has less auxiliary elements and less voltage and current stress compared to similar soft switching interleaved flyback converters. The introduction of a new auxiliary circuit for soft switching, in addition to increasing efficiency, minimizes the number of added semiconductors. Also, another advantage of this structure is the applicability of the provided auxiliary circuit to other isolated converters. The soft switching conditions in this converter are created by the auxiliary circuit in such a way that the converter switches turn on and off under ZVS conditions and the converter diodes turn on and off under ZCS conditions. The efficiency of the proposed ZVS interleaved flyback converter at full load is increased by 5%. Another advantage of the proposed converter is that the Q2 switch, in addition to providing zero voltage switching conditions for the Q1 switch, it also transmits energy and increases the density of the converter power and reduces the current stress. The converter is thoroughly analyzed and a 300W laboratory prototype is made to confirm its correct operation and practical results are presented. Manuscript profile -
Open Access Article
9 - Investigation of the Girth Size and intervals Effect on Lateral Buckling Strength of Built-up Double I & C-Sections Columns
jaber hemayati ahmad rahbar ranji Steel composite columns with parallel girth are one of the common types of columns used in steel structures in the country (IRAN). Despite many studies on the behavior of these columns, the impact dimensions and spacing of girth on t More Steel composite columns with parallel girth are one of the common types of columns used in steel structures in the country (IRAN). Despite many studies on the behavior of these columns, the impact dimensions and spacing of girth on the buckling load of these columns have been less considered. In addition to resistance criteria, in designing of pressure members, the stability criteria must also be considered. In other words, the pressure members of a structure will be defeated effectively by local buckling before reaching maximum compressive strength or influence of buckling phenomenon. The local buckling is one of the common instability of structural members and is an important factor in design of the Built-up columns, so the buckling phenomenon of these columns must be strongly controlled. In this research, 10 columns by double I sections and 6 columns by double C sections were analyzed by different intervals of girths. All column sections are double IPE140 or UNP140. Dimensions of the girth in double I sections are 100×180 mm, with thickness of 4, 6 and 8 mm, by intervals axes to axes 400, 600 and 800 mm in both side. Dimensions of the girth in double C sections are 100×140 mm, with thickness of 4 and 6 mm, by intervals axes to axes 400, 600 and 800 mm in both side. Finally, the elastic buckling load of these columns was obtained by using the Abacus finite element software and compared with the relationships in the tenth chapter of the National Building Regulations. Manuscript profile -
Open Access Article
10 - Supplying Three Phase, Four Wire, Unbalanced and Non-Linear, Asymmetric Ohmic-Inductive Load by NPC Inverter Based on Method Predictive Control
Alireza Poolad Mahdi Shahparasti Majid Hosseinpour -
Open Access Article
11 - تحلیل ارتعاشات آزاد ورق ساندویچی دایره ای با رویه های هدفمند تحت شرایط تکیه گاهی گیردار
یونس محمدی کیوان حسینی صفری محسن رحمانیدر این پژوهش ارتعاشات آزاد ورق ساندویچی مدور گیردار با رویههایی از مواد با تابع هدفمند وابسته به دما در محیطهای حرارتی مختلف بررسی شده است. خواص مواد در رویههای هدفمند به صورت تابعی از دما در نظر گرفته شده و به طور پیوسته در امتداد ضخامت، با توزیع توانی بر حسب کسر حج Moreدر این پژوهش ارتعاشات آزاد ورق ساندویچی مدور گیردار با رویههایی از مواد با تابع هدفمند وابسته به دما در محیطهای حرارتی مختلف بررسی شده است. خواص مواد در رویههای هدفمند به صورت تابعی از دما در نظر گرفته شده و به طور پیوسته در امتداد ضخامت، با توزیع توانی بر حسب کسر حجمی اجزای تشکیل دهنده، تغییر میکنند. همچنین خواص ماده در هسته نیز وابسته به دما در نظر گرفته شده است. معادلات حاکم بر حرکت در ارتعاشات آزاد در دستگاه مختصات قطبی با استفاده از اصل همیلتون به دست آمده و از روش گلرکین برای حل معادلات و به دست آوردن فرکانس طبیعی استفاده شده است. تنشهای صفحهای هسته که معمولا در مشخصه ارتعاشی سازههای ساندویچی نادیده گرفته میشوند در اینجا در نظر گرفته شده است. نتایج به دست آمده از حل گلرکین برای ورق ساندویچی دایرهای متقارن با تکیهگاه گیردار با نتایج المان محدود که توسط نرم افزار ABAQUS به دست آمده است، مقایسه شده که نتایج قابل قبولی را ارائه میدهد. نتایج نشان میدهد که تغییرات دما و تغییرات توان تابع توانی اثر مهمی بر تغییرات فرکانس دارند. Manuscript profile -
Open Access Article
12 - Frequency responses analysis of clamped-free sandwich beams with porous FG face sheets
Mohsen Rahmani