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List of Articles
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Open Access Article
1 - Analytical Modified Model of Cold Rolling Process and Investigation of the Effect of Work Roll Flattening on the Rolling Force
Mohammad Heydari Vini Pedram FarhadipourCold rolling of steel is one of the most important metal forming processes so an accurate control ofits parameters during the process is necessary. In this paper, the friction coefficient has beenproposed as a function of cold rolling parameters such as forward slip, fo MoreCold rolling of steel is one of the most important metal forming processes so an accurate control ofits parameters during the process is necessary. In this paper, the friction coefficient has beenproposed as a function of cold rolling parameters such as forward slip, forward and backwardtensile stresses ,strip thickness, static deformation, resistance of strip before and after rolling ,stripvelocity before and after rolling and work roll diameters. A cold rolling model for computation ofrolling pressure and force with varying friction coefficient and work roll flattening is proposed. Thefinal results obtained from calculations were very close to the experimental results and there hasbeen a good compliance with this method results and other researches and this is the advantage ofthis model. Finally the rolling forces in two stands with three passes were measured. So, the resultsdemonstrated that an actual process in the two stand reversing cold mill by increasing the work rollflattening the rolling force increased considerably. Also, by increasing the tensile stresses at the endof the steel strip, the rolling force decreased. Manuscript profile -
Open Access Article
2 - Experimental Investigation of Subsurface Damages Made by Cup Grinding and Lapping Process of Optical Glass BK7 in Ductile Mode
Vahid Barahimi Masoud FarahnakianConventional material removal of BK7 optical glass will normally result in brittle fracture at thesurface, generating severe subsurface damage and poor surface finish. Subsurface damages inducedby grinding strongly influence the mechanical strength and optical quality o MoreConventional material removal of BK7 optical glass will normally result in brittle fracture at thesurface, generating severe subsurface damage and poor surface finish. Subsurface damages inducedby grinding strongly influence the mechanical strength and optical quality of optical glasses.However, through ductile mode grinding it is possible to reduce the surface and subsurface cracks.It is meaningful to evaluate the depth of subsurface cracking through the measurement of surfaceroughness under different grinding parameters. In this research, the surface and subsurface damagesduring micro cup grinding and lapping process of optical glass BK7 are being investigated. In orderto invest the subsurface damages, cross section polishing method is being used and the crosssections are inspected through SEM microscope. The results indicate that number of subsurfacemedian cracks after lapping process are strongly decreased and surface lateral cracks are extendedall over the sample's ground surface. Manuscript profile -
Open Access Article
3 - Design and Fabrication of a Longitudinal-Torsional Ultrasonic Transducer
Yahya Radi Najafabadi Reza Nosouhi Frahad SajajidA hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. Thedesign of the transducer was performed using the FE method with ABAQUS software, with the aimof combining the longitudinal and torsional vibration modes. The transducer MoreA hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. Thedesign of the transducer was performed using the FE method with ABAQUS software, with the aimof combining the longitudinal and torsional vibration modes. The transducer horn is then fabricatedusing a 4-axis milling machine. The PZT stacks are employed in order to excite the transducer. Thetransducer body is fabricated with grade 5 titanium for its appropriate mechanical properties. Thetransducer is then assembled and the experimental tests are carried out to measure the vibrationamplitude in both longitudinal and torsional directions using an Eddy current displacement sensor.Theresults showed that the resonance frequencies of both the torsional and longitudinal modes arethe same and experimental results are in good agreement with the FE results. The transducer can beused as a vibration tool for vibration assisted drilling which can produce both longitudinal andtorsional vibrations. Manuscript profile -
Open Access Article
4 - An Optimization on the DIN1.2080 Alloy in the Electrical Discharge Machining Process Using ANN and GA
Masoud Azimi Amin Kolahdooz Seyyed Ali EftekhariElectrical Discharge Machining (EDM) process is one of the most widely used methods formachining. This method is used to form parts that conduct electricity. This method of machininghas used for hard materials and therefore selects the correct values of parameters which MoreElectrical Discharge Machining (EDM) process is one of the most widely used methods formachining. This method is used to form parts that conduct electricity. This method of machininghas used for hard materials and therefore selects the correct values of parameters which are soeffective on the quality machining of parts. Reaching to optimum condition of the DIN1.2080 alloy(D3) machining is very important due to the rapid and widespread use of different industry such asMolding, lathe tools reamer, broaching, cutting guillotine and etc. Therefore the purpose of thisstudy is to consider the effect of the inlet parameters such as current, voltage, pulse on time andpulse off time on the machining chip rate and optimize the inlet parameters for D3 alloy. So toreach better result after doing some experiments to predict and optimize the rate of removing chip,neural network method and genetic algorithm are used. Then optimizing input parameters tomaximize the rate of removing chip are performed. In this condition by decreasing time, the productcost is decreased. In this condition, the optimum parameters are obtained under the current of 20(A), 160 (V), pulse on time of 100 (ms) and pulse off time of12 (ms). At this condition, the rate ofmachining chip is obtained 0.063 (cm3/min). Also, surveying the level of error and its accuracy areevaluated. According to the obtained error value that is about 5.18%, the used method is evaluatedsuitable for genetic algorithm. Manuscript profile -
Open Access Article
5 - Designing a New Model for Evaluating the Maintenance System
Abolfazl Sherafat Sayyed Mohammad Reza DavoodiThe previous studies about the maintenance systems were dealt with defining the evaluation criteria,grouping them, and using different techniques for evaluating. The main problem is that maintenancesubsystems and the relationship between and within them in order to a re MoreThe previous studies about the maintenance systems were dealt with defining the evaluation criteria,grouping them, and using different techniques for evaluating. The main problem is that maintenancesubsystems and the relationship between and within them in order to a reliable evaluation havenever been identified before.The contribution of this study is realizing the four maintenance subsystems consisting service andmaintenance, inspection, chronic failure, and severe failure and investigating the communicationbetween them that has never been done in previous studies. On the other hand, in each subsystemthe relationship between causal conditions, phenomenon, mediator condition, strategies andconsequences that had been neglected in previous studies are discussed for the very first time.Causal conditions, that cause each of four subsystems, are identified. Then phenomenon andmediator conditions are presented and the strategy that should be made based on the characteristicof phenomenon and mediator condition is determined as well. Since making a strategy can lead to aconsequence, the consequences according to different strategies are identified that has never beendone in previous studies. At last, the relations between these parts are presented in narratives. Manuscript profile -
Open Access Article
6 - Stress Concentration Factor in a Functionally Graded Material Plate around a Hole
Javad Jafari Fesharaki Seyed Ghasem Madani Davood SeydaliStress concentration factors have been examined in a functionally graded material (FGM) plate withcentral holes in different shapes in this essay. The material properties change along the thickness ofplate. ABAQUS software has been utilized for modeling of problem in wh MoreStress concentration factors have been examined in a functionally graded material (FGM) plate withcentral holes in different shapes in this essay. The material properties change along the thickness ofplate. ABAQUS software has been utilized for modeling of problem in which subroutine ofABAQUS sub-program was used for modeling of the targeted material. The considering shapes forhole in plate are circular and elliptical in which stress concentration factors have been studied indifferent modes in respective of ellipse diameters. Similarly, stress concentration factors have beenanalyzed in the plate for various coefficients of FGM function. The results show that changes inmaterial properties and the shape of hole in plate affect the stress concentration factor around thehole. An experiment was implemented to determine verification of results from Finite ElementMethod (EFM). Manuscript profile
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