| Project/Area Number |
63560245
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
農業機械
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
UENO Masami University of The Ryukyus, Agriculture, Associate Professor, 農学部, 助教授 (50145546)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1990: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Finite Element Method / Soil-Machine System / Soil-Machine-Man System / Simulation / Interaction / Relative Slip / Slip-Traction Relation / 土一機械系 / 相乗効果 / 固有振動解析 / 動的問題 / 土壌-人-機械結合系 / クロ-ラの挙動 / ロ-タリ耕耘 / 平板沈下 / 車輪転動 / すべり沈下 / 土-機械系 / 有限要素解析 / 結合力学系 / トラクタ / 弾塑性構成式 |
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| Research Abstract |
1) Numerical Simulations for Mechanical Interactions of a Tractor.
This study aimed to develop a new method for analyzing mechanical behaviors of tractor in plowing by using Finite Element Method. This method had a distinctive feature which analyzed the interactions of machine and soil behaviors as a soil-machine combined system. At first the plowing problems were tried to simulate by this method. In addition, behaviors of a crawler shoes and problems of rotary tillage by a power tiller were analyzed by this method. The latter was categorized as a problem of soil-machine-man system. The tractor body was expressed with beam elements and the soil was done with continuous elements i. e. a triangle one. Skeleton and muscle of the operator were modeled with beam elements. Programs were written by a BASIC and personal computers (16 bits CPU machine) were used. Simulations of these systems were executed under the various conditions. These were performed to change the values of material constan
… More
ts, the tractive force of tractor, the depth of soil layer to the hard pan, the weight of tractor and the size of elements. The results represented qualitatively such mechanical behaviors. This method could be applied not only to the design tool such as CAD but to an educational tool in the field of tractor mechanics.
2) Finite Element Analyses for Mechanical Behaviors of a Wheel.
A finite element method was developed to analyze rotating behaviors of a tractor wheel. The soil was regarded as an elastoplastic body. The constitutive equation of this FEM was based on the Subloading Surface Model which described the smooth transition process from the elastic state to the plastic one. Boundary conditions at the contact surface between the wheel and the soil which was major difficulty for a successful analysis of this problem was given by constraint displacements to these nodes. A concept of relative slip was introduced to suit such boundary conditions. The ratio of normal and tangential forces at the contact node was checked every incremental stages. If the ratio exceeded frictional coefficient, the constraint displacement increment was modified by the use of relative slip until to satisfy the frictional conditions. The motion of wheel which went down vertically at first and rotated secondary were expressed as two different stages in the calculation. The results gave useful information to the stress and strain distributions, relationships between the slip and traction, the slip sinkage and so on. Less
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