M. Rahmatian; S. H. Karparvarfard; M. A. Nematollahi; A. Sharifi Malvajerdi
Abstract
All over the world, farmers choose different implements for tillage, which depend on crop type, soil type, the amount of plant residue from the previous crop, etc. Tillage implement selection is also affected by the availability of implements, power consumption, labor costs, and fund. In this research, ...
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All over the world, farmers choose different implements for tillage, which depend on crop type, soil type, the amount of plant residue from the previous crop, etc. Tillage implement selection is also affected by the availability of implements, power consumption, labor costs, and fund. In this research, the draft force, soil disturbance area, soil cone index, and fuel consumption were considered. The effects of rake angle, forward speed, and soil moisture content on the above-mentioned parameters were investigated. In this research, a comparison between the performance of a Fiber Reinforced Polymer (FRP) composite blade and a conventional steel blade was carried out. Tests were based on the split-split plot in a completely randomized design. The factors of soil moisture content, rake angle, and forward speed were included in three levels. Three levels for the soil moisture content (9.3, 13, 16.7 %), rake angle (20°, 30°, 40°), and forward speed (3, 5, 7 km.h-1), were considered. The FRP composite blade (on average in the desired range for variables) has reduced the draft force, fuel consumption, and soil cone index, 14.97%, 16.63%, and 35.08%, respectively, than the steel blade. Also, the soil disturbance area created by the FRP composite blade was 4.93% higher than the steel blade. Based on the results of this study, it is clear that the FRP composite blade has better performance rather than the conventional steel blade for the aforementioned test variables. The FRP composite is inexpensive than the steel, this leads to remarkable save money in the production of the FRP composite blade used in the chisel and combined tillage tools that is economical for the farmer and manufacturer.
Modeling
M. Rahmatian; R. Yeganeh; M. A. Nematollahi
Abstract
IntroductionTillage is a very important operation that influences the growth and productivity of agricultural products. It is necessary to introduce some conditions to improve soil physical properties, aeration, permeability and root development in tillage operations. However, in primary tillage, especially ...
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IntroductionTillage is a very important operation that influences the growth and productivity of agricultural products. It is necessary to introduce some conditions to improve soil physical properties, aeration, permeability and root development in tillage operations. However, in primary tillage, especially when moldboard ploughs are used, this may be time consuming and costly for researchers to use it in their research. Some researchers use physical experiments to perform the work, which the accuracy of the results is dependent on the measuring instruments precision. However, some other researchers use simulation and mathematical modeling to reduce the time and costs and increase the relative accuracy of the research results. Many studies have also shown that modeling the forces involved in tillage is a good way to estimate the performance of different tillage tools and improve their geometry. However, the key to success in numerical simulation of tillage operations is to simulate the exact instrumentation, based on the correct assumptions as well as the proper methods. The prediction of the forces involved in tillage tools has an important role in their design. Collecting data on the forces involved in tillage tool under different farm conditions is a time consuming and costly task. Therefore, the prediction of a tillage tool forces is very important for the designer and the user in order to achieve better performance of the tool. Materials and MethodsIn this study, a cylindrical moldboard made by Alpler Company in Turkey was used to simulate the moldboard. A measuring device was designed and constructed to measure the various points of the desired moldboard. Then, the spatial points obtained by the measuring device were presented to the SolidWorks 2016 software and the desired moldboard was modeled. The finite element method by Abacus 2016 was then used to simulate the interaction between soil and moldboard. Treatments used in simulated tillage operations included tillage depths (5, 10, 15, 20 and 25 cm) and forward speed (1, 1.5, 2, 2.5 and 3 millimeters per second). The independent variables were considered as tensile, vertical and lateral forces (Kilo newton). After simulating the tillage operations, tensile, vertical and lateral forces were obtained. These forces were modeled using response surface and artificial neural networks techniques. Then, the obtained models were compared using R2, RMSE and MRDM statistical indices and the best model was selected. Results and DiscussionWhen using the response surface method, the quadratic model was selected by using the maximum value of the statistical indices R2, R2a and R2p, among the linear, two-factor and quadratic models. Then, the significance of model variables was evaluated by using variance analysis. The forces were also modeled by using the neural network method. According to the fitting curves and statistical indices of R2, RMSE and MRDM for the tensile, vertical and lateral forces, it is revealed that both methods could well predict the forces but artificial neural network was more suitable than the response surface method. Moreover, by investigating the interactions of tillage treatments and forward speed on the forces in this research, it was observed that by increasing the depth of tillage and velocity, tensile, vertical and lateral forces were increased nonlinearly by 66.55%, 68.47%, and 64.76%, respectively. ConclusionRegarding all the results obtained from this study, it can be concluded that the developed models using the artificial neural network in this research was a good and powerful tool for predicting the forces involved in moldboard ploughs both in the field operations and in related studies. It is also recommended that the developed models in this study can be used to manage the tillage operations, such as selecting the proper tractor. However, it is also suggested that other affecting factors, such as moldboard angles, should be included in future models to increase the ability of the model to predict the forces involved in moldboard plows.
M. Mohammadi; S. H. Karparvarfard; S. Kamgar; M. Rahmatian
Abstract
Introduction Due to problems such as water resources constraints, poor soil and soil organic matter, and the problems related conventional tillage, the attention paid to protective tillage equipment should be taken into consideration by farmers. Today, agricultural machinery designers and manufacturers ...
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Introduction Due to problems such as water resources constraints, poor soil and soil organic matter, and the problems related conventional tillage, the attention paid to protective tillage equipment should be taken into consideration by farmers. Today, agricultural machinery designers and manufacturers are looking for ways to resolve the problems due to the lack of water and soil resources and the reduction in fuel resources. One of these solutions is the optimization of agricultural machinery. The blade is one of the most important consumed components of tillage tools, which is very important for how it is adjusted and its effect on soil. According to research conducted on the importance of optimizing tillage implements, this study was carried out with the aim of optimizing the operating conditions for combined tillage with a new narrow blade. Materials and Methods The tests were taken place in the 10th section of farms in Agriculture school (Bajgah zone) of Shiraz University. Those tests were arranged as the split-split plot based on a completely randomized design. The treatments included the tillage depth, tilt angle and forward speed. The levels for the tillage depth, tilt angle and forward speed were 15, 20 cm and 0, 10, 15, 20, 25 degree and 3, 4, 5 km h-1 respectively. The experiments were performed in three replications. The test variables were draft, soil upheaving and disturbance areas, specific draft, fuel consumption and tractor wheel slippage. The CK 45 steel was used to make blades. The blades were made of the same dimensions and the difference between the blades was only at their tilt angle. Before starting the field tests, some properties of soil such as soil moisture content, soil texture and soil bulk density were measured. The RNAM test code was then used for measuring the draft force. The encoder and the fifth wheel were also employed to measure the slippage. For measuring the fuel consumption, two flow meters were used in the round way. The profilometer was applied for measuring the soil upheaving and disturbance areas. The specific draft was also computed. The data analysis was performed by SAS software (9.4 edition). Multiple regression method was used for modeling the desired treatments. Results and Discussion The results of multivariate regression method for optimizing forward speed, tillage depth and tilt angle for the blades including winged were 3.3 km h-1, 20 cm and 25°, respectively, and for the non-winged, 3.5 km h-1, 20 cm and 24.8°. Providing the tilt angle on the blade surface is considered as an innovation in this research, therefore, it can be seen from the results that with increasing this angle, the draft of the tillage was decreased. This could be due to the increased surface of the blade in the face of the soil on the diagonal surface. This increase was proportional to the cosine tilt angle at the initial surface of the blade. Therefore, the shear strength of the soil was decreased with increasing of this surface and ultimately decreased the amount of draft of the tillage. This variable had a significant difference with the depth of tillage and the forward speed of tractor and fuel consumption for the winged new narrow blade. Although the interactions of the above mentioned variables on the fuel consumption for the new blade condition were not significantly different, the minimum fuel consumption for the non-winged blade condition was also obtained at the same tilt angle as the winged new blade. In general, considering all of factors, the 25 degree inclination angle was proposed for both conditions. The interaction of this factor (tilt angle) on the wheel slip rate was also significant. The effect of the angle of inclination for both blades was significant on the slip of the wheel drive, so that the increase in the tilt angle reduced the amount of wheel slip. However, if the amount of slip of the tractor's wheel for an optimum angle of 25° was considered, according to the graph which representing the relationship between tractive efficiency vs. wheel slip and for Cn = 50, the tractive efficiency will be determined by calculation. It should be noted that the tractor's tractive efficiency was equivalent to 82%. This value reflects the effect of the tilt angle on the amount of tractor output power according to the definition of the tractive efficiency of the tractor. Conclusion Considering the increasing growth of using combined tillage tools in dry soil and its low moisture content, and considering the necessity of replacing the custom chisel blades with new blades which resistance to the soil reaction forces upon them, the non- winged blades with the tilt angle about 25° for working depth of 20 cm and forward speed of 3.5 km h-1 can increase the tractive efficiency of tractors to 82% and also decrease the fuel consumption by 34% compared to conventional tillage blades.
