Modeling
R. Khodabakhshian; R. Baghbani
Abstract
The present study aimed to examine the application of accurate and principle-based evaluation of a measuring instrument called the Form Tester in determining and detecting the wear phenomenon in the cylinder liner of agricultural tractors. For this purpose, a cylinder liner of the Perkins 4-248 engine ...
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The present study aimed to examine the application of accurate and principle-based evaluation of a measuring instrument called the Form Tester in determining and detecting the wear phenomenon in the cylinder liner of agricultural tractors. For this purpose, a cylinder liner of the Perkins 4-248 engine (related to the Massey Ferguson 285 tractor) was manufactured by Keyhan Sanat Ghaem Company was used. The geometric parameters that were measured in this research included roundness, straightness, and concentricity of the cylinder liner. The evaluations on roundness and concentricity of cylinder liner were conducted in 12 circular positions with the same longitudinal distances. The straightness was measured in five lines with the same longitudinal distances in 90° around the cylinder liner environment. The results of the measurements were discussed and analyzed to evaluate the engine status along the functional path of the piston within the cylinder liner. The degree of deviation rate of the parameters indicated significant wear within the cylindrical liner. The wear rate in cross-sections at high and low dead points was significantly greater than that of the same cross-section in the vicinity of the midpoint of the piston movement path inside the cylinder, as well as the cross-sections near the high dead point. The results of this research provide feedbacks for engine designers to apply various changes to the engine and for maintenance and repair engineers to ensure the correct implementation as well as preventive and predictive repair and maintenance strategies.
H. Taghizadeh; M. Ziyaei Hajipirlu; V. Khederli; B. Shamsi
Abstract
Introduction Discovering and understanding customer needs and expectations are considered as important factors on customer satisfaction and play vital role to maintain the current activity among its competitors, proceeding and obtaining customer satisfaction which are critical factors to design a successful ...
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Introduction Discovering and understanding customer needs and expectations are considered as important factors on customer satisfaction and play vital role to maintain the current activity among its competitors, proceeding and obtaining customer satisfaction which are critical factors to design a successful production; thus the successful organizations must meet their needs containing the quality of the products or services to customers. Quality Function Deployment (QFD) is a technique for studying demands and needs of customers which is going to give more emphasis to the customer's interests in this way. The QFD method in general implemented various tools and methods for reaching qualitative goals; but the most important and the main tool of this method is the house of quality diagrams. The Analytic Hierarchy Process (AHP) is a famous and common MADM method based on pair wise comparisons used for determining the priority of understudied factors in various studies until now. With considering effectiveness of QFD method to explicating customer's demands and obtaining customer satisfaction, generally, the researchers followed this question's suite and scientific answer: how can QFD explicate real demands and requirements of customers from tractor final production and what is the prioritization of these demands and requirements in view of customers. Accordingly, the aim of this study was to identify and prioritize the customer requirements of Massey Ferguson (MF 285) tractor production in Iran tractor manufacturing company with t- student statistical test, AHP and QFD methods. Materials and Methods Research method was descriptive and statistical population included all of the tractor customers of Tractor Manufacturing Company in Iran from March 2011 to March 2015. The statistical sample size was 171 which are determined with Cochran index. Moreover, 20 experts' opinion has been considered for determining product's technical requirements. Literature and theoretical bases of this study have been collected with research paper tab and the research data has been collected through four researcher-made questionnaires and interview tools. The questionnaire Type 1, used for determining the most important demands and needs of customers based on five choices Likert scale. The questionnaire Type 2 was for gathering data requirements to hierarchical AHP method, and the questionnaire Type 3 was for doing some evaluation about organization's present situation related with competitor's situation based on customer's demands and needs; and the questionnaire Type 4 had been implemented for finding technical requirement weights respect to customer's demands and needs. The reliability of the type 1, 3 and 4 questionnaires determined by Chronbach's Alpha method; after gathering required data for mentioned statistical test, these questionnaires' reliability rates are obtained: 0.768, 0.784 and 0.793, respectively. As well as, the validity of the questionnaires has been examined with content validity method. In this research, for analyzing the gathered data, while taking into account the different stages of QFD method, t- student statistical test was used for identifing the needs and demands of customers, and AHP was used for determining the priority of needs and demands of customers. Results and Discussion The results of one sample t-test for identifying the customer’s most important demands and needs showed that the factors such as: producing low price tractor, the quality of used auto-parts, sustainability and long-lasting the final production (production life and durability), comfort and peace during work, creating operator cabin, easy access to spare components, the amount of fuel consumption, warranty and maintenance, easy access to official repair stations, technical experts and suitable auto-parts, fast respond of brake system during braking and smooth moving identified the important demands and needs of customers. The results of AHP method for determining primary priorities of perceived customers needs and demands revealed as follows respectively: quality of parts, warranty and maintenance, low price, fuel consumption, comfort and peace, life and durability, smooth moving, fast respond of brakes, creating operator cabin and easy access to spare components. Finally, the main demands and related technical requirements have been identified and prioritized with QFD method; the Final results of customer demands and needs by QFD method revealed this prioritization: Quality of Parts, Warranty And Maintenance, low price, Fuel Consumption, Peace and Comfort, Life and Durability, Smooth Movement and lower engine knocking, Fast Respond of Braking System, Creating Operator Room and Easy Access to Components. Conclusion Without any doubt it is obvious that the obtaining customer satisfaction is the most important strategic tool for having successful and highly developed industry in this era. Knowing the customer demands and needs can lead the organization to enhance competitive advantages. This research showed that how could use structured QFD method for identifying prioritization of tractor customer demands and needs for maintain their satisfaction, and identifying importance of each demands, considering the production techniques.
Kh. PashaiHulasu; B. Mohammadi Alasti; M. A. Haddad Derafshi; M. Abbasgholipour
Abstract
Introduction: Tractors are considered as the main power generators in mechanized agriculture. Hence, the experts and engineers in tractor manufacturing of the country, are required to focus on developing and designing new features in tractor manufacturing. This must be, of course, paralleled with the ...
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Introduction: Tractors are considered as the main power generators in mechanized agriculture. Hence, the experts and engineers in tractor manufacturing of the country, are required to focus on developing and designing new features in tractor manufacturing. This must be, of course, paralleled with the economic aspects. Achieving this goal, Iran Tractor Manufactories Co., (ITMCO) has designed and developed tractors equipped with turbochargers. This has been performed on ITM800 & ITM485 models, according to world standards. The turbocharger system, with harnessing of lost energy in engine output fumes, compresses the air entering the engine and more air enters the cylinder. This will cause the engine to burn fuel more efficiently and thus produce more power.
Materials and Methods: This study has been carried out on ITM485 & ITM800 tractors (with turbocharger system) and ITM285 & ITM475 tractors (without turbocharger system) to assure the improvement of engine performance and compare them employing OECD world standards. Experiments were performed in the concrete runway of Tabriz Tractor Manufacturing Company. For experiments, a dynamometer was used to measure the traction force between two tractors, a measuring unit for fuel, a thermometer unit and a timer to measure the quantities of fuel consumption, drawbar force and power. For drawbar traction test, each of the tested tractors pulled the rear tractor in different gears and the dynamometer between these 2 tractors recorded the tractors traction force by data loggers. To measure tractors fuel consumption, a measuring unit of fuel (VDO - EDM 1404) was used that calculated the flow rate in the path of fuel from the fuel tank to the engine and the return path from the engine to the fuel tank and showed the quantity of fuel consumption in liters per hour digitally.
Results and Discussion: In comparison of traction power and force of tractors with turbochargers and without turbochargers in different gears, the results of variance analysis showed that the effect of tractor was significant. Traction power and force at tractors with turbochargers ITM485 and ITM800 and without turbocharger ITM475 have a significant difference in the level of one percent. Tukey post hoc test results also indicate that traction power and force in tractors with turbochargers ITM485 and ITM800 are significantly more than the tractor without turbocharger ITM475. The gear effect is also significant. Traction power and force in different gears have significant difference at the probability of one percent. Tukey post hoc test results indicate that power quantity is highest in the gears: (1+H, 2*H, 1*H, 3+L) and minimum in the gears: (1*L, 1+L, 2*L), (* Turtle and + Rabbit). But Tukey post hoc test results indicate that traction force quantity is highest in the gears: (1*L, 2*L, 1+L) and minimum in the gears: (2*H, 1+H). In the comparison of specific fuel consumption of tractors with turbochargers and without turbochargers in different gears, the results of variance analysis showed that the effect of tractor was significant. The amount of specific fuel consumption at tractors with turbochargers ITM485 and ITM800 and without turbocharger ITM475 has a significant difference in the level of one percent. Tukey post hoc test results also indicate that specific fuel consumption quantity in tractors with turbochargers ITM485 and ITM800 in the level of one percent is significantly less than the tractor without turbocharger ITM475. The gear effect is also significant. The specific fuel consumption quantity in different gears has significant difference at the probability of one percent. Tukey post hoc test results indicate that specific fuel consumption quantity is highest in the gears: (1*L, 1+L, 2*L) and minimum in the gears: (1+H, 2*H, 1*H).
Conclusions: The tests were performed on tractor drawbar traction. Results of variance analysis in this experiment on a concrete surface, indicated that the calculated traction power and force of ITM485 and ITM800 tractors (with turbocharger system) were higher than the ITM475 & ITM285 tractors (without turbocharger) and this difference was significant at the one percent level of probability. Meanwhile specific fuel consumption in the ITM485 and ITM800 tractors (with turbocharger system) was lower than that of the ITM475 & ITM285 tractors (without turbocharger) and this difference was significant at the one percent level of probability. This will lead to significant savings in fuel consumption.
M. A. Rostami; A. Javadi; M. Heidari Soltanabadi; A. Mehdinia; M. Shaker
Abstract
Introduction: Different models of tractors have been imported from foreign countries or assembled in Iran for many years. Consistency of foreign manufactured products with native specifications and the improvement of locally manufactured tractors are important problems that must be considered. Moreover, ...
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Introduction: Different models of tractors have been imported from foreign countries or assembled in Iran for many years. Consistency of foreign manufactured products with native specifications and the improvement of locally manufactured tractors are important problems that must be considered. Moreover, tractor dimensions, sitting space and some other important factors such as the ability of Iranian users to operate them must be taken into consideration. In this study, we surveyed the proper proportion of tractors dimension, location of control tools and driver’s work space, with Iranian users’ anthropometric data of drivers from five provinces. Human factors are of paramount importance in developing farm machinery given that these machines will often be operated by persons with minimum skills. Therefore, farm machinery should be made simple to operate and as free from hazards as possible.
Materials and methods: Firstly, the anthropometric data for 250 users 20-60 years old was calculated. The drivers were selected randomly. Then the specifications of 4 tractors including: Ferguson 285, Ferguson 399, Valtra and New Holland were compared with the anthropometric data of user in 5th and 95th percentile value and their adaptation was studied. Anthropometric Data of subjects consisted of: standing height, full hand length, popliteal length, seat pan width, seat pan depth, elbow height, seat back support height, hand pan width, hand grip and full-leg length. Getting on the tractor is the first contact of an operator with a tractor. In assessing the suitability of the provision made for getting on the tractor, an experiment was arranged in which operators tried to get on 3 tractors. The mode of getting on the tractors, the agony on the operator’s face, the muscular reactions and individual opinion on the difficulties or comfort while undertaking the task were observed and recorded. The specifications of tractors compared with Anthropometric Data were measured, whiles the tractors were positioned on a level ground for measurements after the tires had been ganged. These specifications were tractor height, steering wheel height, footrest height, foot set height; tractor seat geometry as seat pan width, seat pan depth and seat pan support height; steering geometry as distance of steering wheel from seat reference point, steering wheel radius, steering wheel thickness, steering wheel inclination to the horizontal and seat reach adjustment; levers and pedals distance from seat reference point as gear lever, parking brake lever, hydraulic control lever, clutch pedal, accelerator pedal, brake pedal, front panel, workspace width and workspace length.
Results and Discussion: The experiment that was conducted with operators attempting to get on the tractors indicated that tractor steps heights were higher than the desirable limit. Therefore, based on the ideas of the researcher and tractors drivers, getting on all tractors is difficult. With an increase in the number of steps or a decrease in their heights, the desirable condition can be created. Seat depth of new Holland and Valtra tractors were great for drivers in the 5th percentile value. A variable thickness pad can solve this problem. Results of studies indicated that Seat depth of Massey Ferguson 285 and 399 was shorter than driver’s leg length of 95th percentile value. To solve the problem an increase of 10 centimeters to pad height of these tractors was suggested. Seat pad of tractors were short for drivers in the 95th percentile value. Distance of steering wheel from seat reference point (SRP) in Massey Ferguson 285 and Valtra was further than drivers hand length in the 5th percentile value. Therefore, the drivers hand is short for driver’s good operation. Surveys indicated that drivers had problems for gear lever access in Massey Ferguson 399. Therefore, for good access on gear lever we must increase seat stroke range by 5-10 centimeters. The record available from Meteorological Organization indicated that air temperature and rain throughout the year in the study area is between 20 to 40degrees Celsius and 100to 300mm change. Valtra and New Holland tractors having a driver cabs with heating and cooling equipment have the ideal space for the performance of their driver. Massey Ferguson 285 tractor does not have any driver cab and Roll Over Protection Structure (ROPS).
Conclusions: This research was conducted in five provinces of Iran to assess ergonomics of some commonly and new used tractors in Iran containing Ferguson 285, Ferguson 399, Valtra and New Holland. As there was no data base with required details, data was collected directly by personal contact with tractor users. A questionnaire was filled out for each person and anthropometric data was calculated in all provinces for 250 users 20-60 year old that were selected at random. Then relevant specifications of 4 tractors were measured and compared with the relevant anthropometric data of users in the 5th and 95th percentile value and their adaptation was studied. The results indicated that tractor steps, Seat depth, distance of steering wheel and distance of some levers and pedals from seat reference point should be amended.
H. Fallahi; M. H. Abbaspour-Fard; A. Azhari; M. Khojastehpour; A. Nikkhah
Abstract
In this research, the imposed forces on three muscles including: Gastrocnemius muscle, Trapezius muscle and Quadratus lumborum of the tractor drivers during clutching have been studied. The sample included 30 persons and the research was conducted on two domestic tractors including: MF285 and MF399 models. ...
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In this research, the imposed forces on three muscles including: Gastrocnemius muscle, Trapezius muscle and Quadratus lumborum of the tractor drivers during clutching have been studied. The sample included 30 persons and the research was conducted on two domestic tractors including: MF285 and MF399 models. The clutching forces for these tractors were measured as 340 N and 290 N, respectively. The difference between drivers’ knee angle of the two tractors was proved significant at the one percent level. The decrease of pain threshold after 30 seconds and 60 seconds clutching and 60 seconds rest after clutching in MF285 tractor in all three muscles were more than that of MF399 tractor. The impact of clutching on the average decrease of pain threshold, among all the drivers, and for all time intervals, during and after clutching in the Quadratus lumborum muscle for both tractors was more than the other two muscles. In order to reduce the imposed force of clutching for MF285 tractor, some modifications is suggested. In this regard the force transfer joint between the pedal and the disc in the mechanism of clutching can be replaced with one made of cast iron.
