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  1 - Optimization of electronic boards equipped with the BGA package to improve the response in random vibration
  میلاد شهسواری مسعود عسگری
  In this paper deflection and free vibration of sandwich panel is studied. The core of Sandwich panels is made of hexagonal honeycomb and faces are made of two different materials of Carbon Fiber Reinforced Plastic and K-aryl/epoxy covering. The governing equations are d More

  In this paper deflection and free vibration of sandwich panel is studied. The core of Sandwich panels is made of hexagonal honeycomb and faces are made of two different materials of Carbon Fiber Reinforced Plastic and K-aryl/epoxy covering. The governing equations are deduced from the First order Sheer Deformation Theory (FSDT) and they are solved using Generalized Differential Quadrature Method (GDQM). The classical method in the references is used to verify the DQ method and to show that the applied GDQM method has a good results with compared to the references. Deflection of sandwich panel is investigated with two different load types. Finally natural frequency for the first 4 modes and the two different faces materials are calculated and the effect of various lengths to core thickness ratios and faces to honeycomb core thickness ratios are studied. Further, the effect of foundation stiffness coefficient on deflection and natural frequency are showed. Manuscript profile
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  2 - Deflection and Free Vibration of Sandwich Panel with Honeycomb Core on Winkler Elastic Foundation
  یونس یوسفی حسین وحدانی فر رضا شیرانی محمد دهقانی
  In this paper deflection and free vibration of sandwich panel is studied. The core of Sandwich panels is made of hexagonal honeycomb and faces are made of two different materials of Carbon Fiber Reinforced Plastic and K-aryl/epoxy covering. The governing equations are d More

  In this paper deflection and free vibration of sandwich panel is studied. The core of Sandwich panels is made of hexagonal honeycomb and faces are made of two different materials of Carbon Fiber Reinforced Plastic and K-aryl/epoxy covering. The governing equations are deduced from the First order Sheer Deformation Theory (FSDT) and they are solved using Generalized Differential Quadrature Method (GDQM). The classical method in the references is used to verify the DQ method and to show that the applied GDQM method has a good results with compared to the references. Deflection of sandwich panel is investigated with two different load types. Finally natural frequency for the first 4 modes and the two different faces materials are calculated and the effect of various lengths to core thickness ratios and faces to honeycomb core thickness ratios are studied. Further, the effect of foundation stiffness coefficient on deflection and natural frequency are showed Manuscript profile
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  3 - Investigation of the effect of buckling initiator on energy absorption of thin-walled circular tubes by using of numerical simulation
  فائزه عبدالهی محمد جواد رضوانی
  Cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. However, the main weakness of cylindrical tubes is in the high initial peak load. Therefore, in thi More

  Cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. However, the main weakness of cylindrical tubes is in the high initial peak load. Therefore, in this paper, to overcome this weakness, a buckling initiator is used at the top of the tube. This buckling initiator is a steel rod that is installed by stretching strips at the edge of tubes. In this study, the parameters related to the initiator, including different number of pulling strips N, pre-hit height h and inclined angle of the pulling strips θ are studied. For this purpose, quasi-static simulation was conducted to determine the maximum crushing load, specific energy absorption and crush force efficiency using the software Ls-Dyna. To verify the numerical simulation, the results were compared with experimental testing. The results show that the crashworthiness characteristics and performance of the cylindrical tubes significantly improved with buckling initiator. Manuscript profile
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  4 - Evaluating the impact of length and thread pitch on the stress distribution in dental implants and surrounding bone using finite element method
  مسیح فیروزبخت حامد عجبی نائینی مصطفی پیرمرادیان
  longevity of osseointegrated implants are intensely influenced by biomechanical factors. Control of these factors prevents mechanical complications, which include fracture of screws, components, or materials veneering the framework. In this study, the impact of length a More

  longevity of osseointegrated implants are intensely influenced by biomechanical factors. Control of these factors prevents mechanical complications, which include fracture of screws, components, or materials veneering the framework. In this study, the impact of length and threads pitch of dental implants on the stress distribution and maximum Von Mises stress in implant-abutment complex and jaw bone are studied using finite element method. The implant length changes from 8.5 mm to 13 mm and a range of 0.6 mm to 1 mm is considered for the threads pitch of implants. The maximum stresses are observed in implant-abutment complex, cortical bone and cancellous bone, respectively. Results suggest a length of 13 mm in a pitch of 0.7 mm for implants. Also, an optimal ratio for the pitch and length of an implant is proposed. Manuscript profile
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  5 - Manufacturing a trough parabolic solar collector and predicting its theoretical performance
  محمود تاجی
  The aim of this research was manufacturing a parabolic trough solar collector in which reflecting surface is made of mirror steel rather than usual mirror and also predicting its theoretical performance.by adjusting planar ⩝ -shaped structures parallel to each other and More

  The aim of this research was manufacturing a parabolic trough solar collector in which reflecting surface is made of mirror steel rather than usual mirror and also predicting its theoretical performance.by adjusting planar ⩝ -shaped structures parallel to each other and welding them together, the main supporting structure was assembled and a parabolic-shape Teflon arc was installed in the aperture of each ⩝-shaped structure. Then the steel plate was installed on the main structure to form a parabolic trough surface. Other components were manufactured and assembled according to conventional methods. In order to predict performance, efficiency was formulated as a function of incident angle according to the related theory. By programing in MATLAB, net rate of heat absorption and efficiency were calculated and corresponding diagrams plotted against apparent solar time for several days of the year. The results indicated that when solar radiation was close to vertical, efficiency increased form fifty percent in the morning to sixty at noon and decreased to fifty again in the afternoon. Otherwise it decreased from sixty percent in the morning to fifty at noon and increased to sixty again in the afternoon. Maximum net rate of heat absorption (w/m 2) occurred at noon (450-550) and the minimum at sunrise and sunset (400-450). Although the efficiency of the manufactured collector is slightly different from that of usual ones, less assembly time and cost and higher quality of surface geometry and more durability of reflecting surface are considerable compared with conventional collectors of this type. Manuscript profile
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  6 - Investigation the Milling Strategies Effects on Machining of Convex Surfaces made of Glass/Epoxy Composite
  هادی محمدی هادی اسکندری ایمان دانایی
  In this study the effects of machining parameters such as shearing speed, feed rate, tool diameter and machining depth on different milling strategies i.e. 3D offset, spiral, raster and radial to produce the convex surface made of epoxy/glass composites is investigated. More

  In this study the effects of machining parameters such as shearing speed, feed rate, tool diameter and machining depth on different milling strategies i.e. 3D offset, spiral, raster and radial to produce the convex surface made of epoxy/glass composites is investigated. The effects of mentioned strategies on output parameters such as surface roughness and milling removal rate is also studied. The results show that the output of radial strategy has the minimum roughness with the highest surface quality. The raster strategy gives the maximum roughness with the lowest surface quality. Also it can be seen that in 3D offset strategy, the removal rate is maximum and subsequently the time of machining is minimum. In addition the optimized values of machining parameters to achieve the best conditions for surface smoothness and removal rate is obtained. The results of this work can be used in research and development units of industries for operational purposes. Manuscript profile
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  7 - New laboratory scale Grinding method to predict energy and the feed grindability of mill of Sarcheshmeh Copper Complex
  محمد رزانی ابوالفضل معصومی مسعود رضایی زاده محمد نوع پرست
  One of the factors which are usually difficult to be measured in mills is the grindability and distribution of feed under real situation and in a short time. In the condition of achieving a fast and convenient way to determine these parameters, the proper relationship b More

  One of the factors which are usually difficult to be measured in mills is the grindability and distribution of feed under real situation and in a short time. In the condition of achieving a fast and convenient way to determine these parameters, the proper relationship between energy, hardness and particle size distribution can be obtained. Feed hardness is one of the most important factors in grinding of minerals in mineral-processing process, and this parameter depends on factors, such as the mechanical properties of minerals and collision conditions. The efficient use of energy during grinding of minerals in mills is one of the main objectives of this research. This research tried to provide an experimental method based on real collision conditions in a mill. Nowadays, SAG design test is used for evaluation of grinding circuit in the time of change in feed particle size distribution, size of the ball and the speed of mill, and for the prediction of energy required for complete grinding in AG and SAG mills. In this study, a new SAG design test for measuring the amount of specific energy and feed grindability was suggested and the effect of various parameters on product size distribution and hardness results was assessed. Results show the deviation of the A×b estimated by new method with values of drop weight tests were less than 1.9 percent. This new model can also be used to accurately predict the specific energy and particle size distribution.. Manuscript profile
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  8 - Modal Analysis Turboshaft Test Stand Motor Designed by Using ANSYS
  مجتبی حسنلو سید غلامرضا میرحسینی محمود صادق زاده احمد باقری
  Today, modeling is critical for cognition and analysis of designers in industry field to meet their needs and design based on design requirements and available facilities to accelerate production and development of components of industrial engines. In this study, one st More

  Today, modeling is critical for cognition and analysis of designers in industry field to meet their needs and design based on design requirements and available facilities to accelerate production and development of components of industrial engines. In this study, one structure has been proposed, designed, and analyzed based on turboshaft marine engine type to test this kind of engine in order to use in reality and to meet needs. Analysis conducted on the structure in ANSYS based on turboshaft engine dynamic effects on the structure. At the end of the study, these are exibited mode shapes and natural frequencies of the structure.Today, modeling is critical for cognition and analysis of designers in industry field to meet their needs and design based on design requirements and available facilities to accelerate production and development of components of industrial engines. At the end of the study, these are exibited mode shapes and natural frequencies of the structure.Today, modeling is critical for cognition and analysis of designers in industry field to meet their needs and design based on design requirements and available facilities to accelerate production and development of components of industrial engines. Manuscript profile