design optimization in rotary tillage tool system

Abstract—The design optimization of rotary tillage tool by

the application of Computer Aided Engineering (CAE)-Techniques on the basis of finite element method and simulation method is done by using CAD-Analysis software for the structural analysis. The different tillage tool parts of rotary tillage tools are geometrically constrained by the preparation of solid model, Meshing and Simulation is done with actual field performance rating parameters along with boundary conditions .The energy constrained for the tillage tool applications with 35Hp and 45Hp power tractor and estimated forces acting at soil-tool interface. The resultant effect on tillage blade and whole rotavator assembly is obtained from stress distribution and deformations plots.The proposed work results in identifying sufficient tolerance in changing the dimensions of rotavator frame sections and side gear box for removing the excess weight in a solid section and also to raise the weight of blade for a reliable strength. The present working model with tillage blade is analysed to new design constraints with change of its geometry for the maximum weed removal efficiency by presenting its practical results from the field performance.

Index Terms—Rotary tillage tool, weed removal efficiency,

CAD-Analysis, simulation, structural analysis, von misses stress

I. INTRODUCTION Rotary tiller is a tillage machine designed for preparing

land suitable for sowing seeds (without overturning of the soil), for eradicating weeds, mixing manure or fertilizer into soil, to break up and renovate pastures for crushing clods etc. It offers an advantage of rapid seedbed preparation and reduced draft compared to conventional tillage. It saved 30-35 % of time and 20-25 % in the cost of operation as compared to tillage by cultivator. It gave higher quality of work (25-30 %) than tillage by cultivator.

The design optimization of tillage tool is obtained by reducing its weight, cost and by improving a field performance to high weed removal efficiency .The computer aided design analysis by preparing a three-dimensional solid modelling and finite elements method applications are getting so widespread in the industry. Thus due to undesired stress distributions on its components, it cannot compensate to the operating forces i.e. field environment and results in breakdown and failure due to higher stresses and deformation.

The proposed work develops a computer aided experimental system for design testing and valuation of agricultural tools and equipments. The selected physical model of rotavator is measured with accurate dimensions and

Manuscript received November 11, 2011, revised April 18, 2012. Gopal U. Shinde is with Marathwada Agricultural University, Parbhani

(M.S.) India (e-mail: [email protected]). .Shyam R. Kajale is with S.G.G. I. E.& T. Nanded (M.S.)India (e-mail: [email protected]).

a solid (3-D) model is prepared in CAD-software such as Ansys, Catia, Pro-E, Hyper-mesh etc. by assembling individual parts with detail specifications.

A. Rotavator Assembly Consists of Following Parts 1) Independent Top Mast 2) Single / Multi Speed Gear Box 3) Chain / Gear Cover Part Flange 4) Blades 5) Chain / Gear Cover Part 6) Frame and Cover 7) Adjustable depth skids 8) Offset adjustable frame

B. CAD Model of Rotavator The CAD-Software is used for the preparation of solid

geometry of rotavator according to specification see Fig.1.

Fig. 1. Solid Model as per physical specifications

C. Finite Element Method The following are the three basic features of the finite

element method. a) Division of whole into parts; which allows

representation of geometrically complex domains as collection of simple domains that enable a

systematic derivation of the approximation functions. b) Derivation of approximations functions over each

element; the approximation functions are often algebraic polynomials that are derived using interpolation theory.

c) Assembly of elements, which is based on continuity of the solution and balance of internal fluxes

Gopal U. Shinde and Shyam R. Kajale

Design Optimization in Rotary Tillage Tool System Components by Computer Aided Engineering Analysis

International Journal of Environmental Science and Development, Vol. 3, No. 3, June 2012

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D. CAD-Modeling and Analysis The three important steps in ANSYS programming used

for CAD-modeling and analysis are: a) Preprocessing b) Solution c) Post processing After preparing a solid geometry of rotavator the important

steps are meshing and applying loading and boundary conditions in the preprocessor so that simulation can be run to get a solution and generate results in the post-processor.

E. Mesh Generation (Meshing) After validation of the model next step is generation of

Finite Element Mesh. For the Rotavator SOLID45 elements are used for meshing. A very fine mesh of freedom of the model increases Hence a designer has to model it optimally i.e. placing fine mesh only at critical area; and coarse mesh at other. So that the run time is less and also the accuracy is not much affected.[2]

F. Element Description 1) Solid 45

The solid meshing using SOLID-45 8 NODE 45 element, DOF: UX, UY, UZ Surface meshing by triangular 6 node element

1. Element edge length – 1.5 mm for crankshaft. Because in this, crankshaft model chamfer width is 3 mm, so for better results, we can take two elements in this area.

2. Element edge length- 2 mm for flywheel and Pulley. 2) Beam 188

BEAM188 has six or seven degrees of freedom at each node using BEAM 188 element DOF: UX, UY, UZ and rotation RX,RY,RZ The proposed work is taken for complete finite element analysis of rotavator tillage tool which introduces the use of CAD analysis for the first time in the design and development of Agricultural machine, tools and equipment.

a) Software Tools CAE: Ansys, Nastran, Abacus, Hypermesh, Cosmos CAD: Catia, Solid-work, Solid-edge AutoCAD, CFD: Fluent, Ansys CFX, ICEM-CFD,

b) Design Services Extencore provide top of the line CAD/CAM design services for aircraft components, industrial equipment, Agricultural Implement and machine tool [3].

c) Engineering Analysis Extencore offer engineering analysis and use of CAE based solutions to customers with product development initiatives, to develop word class and reliable products[5],[6].

d) Objectives 1. To prepare a geometric solid model of rotavator by

using -CAD-software 2. To make the finite meshing by using meshing software. 3. To generate a CAD analysis report of rotary tillage tool -components.

4. To make an engineering analysis of rotavator blade and -modify it with significant changes

II. MATERIALS AND METHODS

A. Material The materials are taken from the manufacturing database

of rotavator production system specification drawn by Industry. The Material properties and Soil properties are considered according to following data in the Table I and II as given below.

TABLE I: MATERIAL PROPERTIES:

Sr.No. Material Name

Material Properties

Elastic Modulus (N/mm2)

Poisson Ratio

Density (tons / mm2)

1 High Carbon Steel 1.97 X e11 0.29 7.48 x e-9

2 Cast Iron 1.20 X e5 0.28 7.2 x e-9

3 Mild Steel 2.10 X e5 0.30 7.89 x e-9

TABLE II: SOIL PROPERTIES: Sr.No.

Types of Soil

Soil resistance (Kg/cm2)

Optimum Moisture content (%)

1 sandy 0.2 3.5 2 Sandy loam 0.3

5.8 3 Slit loam 0.35 – 0.5 4 clay 0.4 – 0.56 7.18 5 Heavy loam 0.5 – 0.7 13.30

B. Soil Parameters The soil properties relevant to the design of rotavator were

identified as soil type, moisture, bulk density and cone index. The manners of measurement and characterization of these properties are discussed in the following sections. The type of soil was black soil were experiment was conducted. Moisture content of soil plays an important role for the growth of the crop hence following Soil resistance and Moisture content of soil are considered as given in Table II.

C. Element and Node Count in FE-Model Following table shows the total number of 2d and 3d

elements obtained in FE model of rotavator [7], [8].

D. Modal analysis The frequencies at which vibration naturally occurs, and

the modal shapes which the vibrating system assumes are properties of the system, and can be determined analytically using Modal Analysis. The following table shows an idea about fundamental natural frequencies and higher natural frequencies in Hz. Section 4.1 contains the deformation plot for individual component and assembly for below mention 10 different natural frequency.

III. RESULT AND CONCLUSIONS A rotary tillage tool such as Rotavator is designed in

computer aided design software. The rotary motion and soil surface interaction is considered with respect to the soil Vs. tillage tool dynamics [7]by considering the following factors effecting the tillage operation such as tractor power (hp),


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maximum peripheral force (N), rotavator tyne velocity (m/s), tractor transmission efficiency (0.9 for concurrent revolution and 0.8-0.9 for reversed rotary), soil resistance to 0.7-0.8, radius of rotary (mm) see Table IV

The design analysis executed following results • Maximum Peripheral force on rotary blade 6031.08975

(for35 hp)N and 7041.17 N (for 45hp) • Torque= 270600 N-mm(for35 hp)N and 315920 N-mm

(see appendix-I) The Design analysis of rotavator results with an output file

generated by simulation with respect to yield stress and deformation obtained by using field conditions in the Post processor. The CAE-Analysis Cycle, see APPENDIX-I

A. Modal Analysis The modal analysis as per above stated condition is done

and the results obtained from the table 1 in Appendix VI, it is observed that, the maximum and minimum deformation of 1.923mm and 0.252mm respectively was observed in blade section. See Table III.

TABLE III: MODAL ANALYSIS

Sr. No. Frequency

(Hz)

Max Deformation

(mm)

Remark

(Rotavator component)

1. 3.50509e-2 2.119 Top

2. 0.12474 1.682 Front left

3. 0.13638 1.449 Top Front

4. 0.16626 1.767 Front left

5. 0.18940 2.012 Bottom front

6. 0.22161 1.693 Bottom Front

7. 16.645 4.313 Front

8. 40.799 5.994 Front Corner

9. 56.556 2.883 Top Front

10 66.299 4.242 Bottom Front

B. Structural Analysis The structural analysis as per above stated condition is

done and the results obtained from simulation [10] & [11], it is observed that

1. The displacement Vector Sum and Von Misses Stress is maximum at blade-section such as 6.757 mm and 417.03 Mpa respectively for 35 hp tractor

2. The displacement Vector Sum and Von Misses Stress is maximum at blade- section such as 7.893 mm and 503.21 Mpa respectively for 45 hp tractor[4], See Fig 2.

C. Blade Analysis 1. The maximum Displacement vector sum in: 6.757mm

( 35 hp) and 7.893 mm(45 hp ) 2. The maximum Von Misses Stress: 417.03 Mpa( 35 hp)

and 503.20 Mpa (45 hp) 3. The maximum principle stress for 35 hp tractor is 490

Mpa was observed in blade section. This stress value is less than yield stress of blade material i.e. 690 Mpa

4. The maximum principle stress for 45 hp tractor is 577 Mpa was observed in blade section. This stress value is less than yield stress of blade material i.e. 690 MpaWorking

safety coefficients, displacement and Von Misses for 35 hp and 45 hp tractor rotavator see Table IV

TABLE IV: WORKING SAFETY COEFF. FOR 35 HP AND 45 HP TRACTOR

INDEPENDENT TOP MAST; II) ROTOR WITH BLADE; III) SIDE GEAR BOX PART IV) FRAME AND COVER; V) LEFT SIDE FRAME; VI) RIGHT SIDE FRAME

Part No.

Von Misses Stress (Mpa)

Safety Coefficient

Resultant Displacement

(mm)

Von Misses Stress (Mpa)

35hp 45hp 35hp 45 hp 35hp 45 hp 35hp 45hpI 404.29 471.46 2.19 3.39 404.29 471.46 01.24 1.06II 417.03 503.20 6.75 7.89 417.0 503.20 01.65 1.37III 015.63 018.28 5.65 6.61 015.63 018.28 11.51 9.84IV 016.86 019.67 6.52 7.89 016.86 019.67 10.67 9.15V 056.26 065.61 6.58 7.68 056.26 065.61 03.20 2.75VI 055.38 064.73 6.68 7.60 055.38 064.73 03.25 2.78

Fig. 2. Principle stress &Von misses stress in blade section

The Rotary tillage blade modified and physically tested in

the field operation which was satisfactorily resulted with high weed removal efficiency and excellent soil bed performance.

Fig.3. Saw tooth angular blade of rotavator


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The reverse engineering concept for redesigning and conceptual modifications in the Blade was found to be significant in cereal inter crop secondary tillage operation Fig 3.above mentioned.

Fig. 4. Frequency Vs deformation

APPENDIX-I Computer aided design and engineering analysis of rotavator components

REFERENCES [1] Akinci, I., D. Yilmaz, and M. Canakci. Failure of a Rotary Tiller Spur

Gear. Engineering failure analysis, 12(3): 400- 404. (2005). [2] Altair Engineering. Inc, “Hypermesh Users Guide”, 2003 [3] Anonymous, (1971). Design data book. PSG college of Tech.

Kalaikathir Publications, Coimbatore. [4] Ansys Inc, “ANSYS 8.1 Documentation, Structural Analysis Guide”,

Swansos Analysis System, United state, 2004 [5] Bechly, M. E., and P. D. Clausent. (1997). “Structural Design of a

Composite wind turbine blade using Finite Element Analysis”. Computers & Structures Vol. 63. No. 3, pp. 639-616.

[6] Beeny, J. M., and D. C. Khoo. (1970). “Preliminary investigations in to the performance of different shaped blades for the rotary tillage of wet rice soil”. J. Agric. Engg. Res, 15 (1):27-33.

[7] Ben Yahia, Logue, and M. Khelifi. (1999). “Optimum settings for rotary tools used for on-the-row mechanical cultivation in corn”. Transactions of ASAE, 15(6): 615-619.

[8] David Roylance (2001). “Finite Element Analysis Method”. Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139 February 28

[9] Fielke, J. M, T. W. Reiley; M. G. Slattery and R. W. Fitzpatt. (1993). “Comparision of tillage forces and wear rates of pressed and cast cultivator shares”. Soil and Tillage Research, 25; 317-328.

[10] Ghosh, B.N. (1967). “The power requirement of a rotary cultivator”. J. Agric. Engg. Res., 12 (1): 5-12.

[11] Gill, W. R., and G. E. Vanden Berg. (1996). “Design of tillage tool. In soil dynamics in tillage and traction”. 211-294. Washington, D.C.,U.S.GPO

Gopal U. Shinde was born on 1971 in Parbhani,India. He completed his bachelor of Engineering on Production Engineering in 1994 from Dr.Babasaheb Ambedkar Marathwada University (Dr.B.A.M.U.) and Master’s degree in Mechanical Engineering (Manufacturing Process Engg) from IIT Kharagpur (W.B.) India. Currently Working as a Assistant Professor of Mechanical engg., Department of Farm Machinery and Power, College of Agricultural

Engineering & Technology, Marathwda Agricultural University Parbhani(M.S.)India. He is a Member of scientific societies ISAE, ASABE, APBEES, AAAE, and IEI. He is CAD/CAM/CAE-Lab in-charge.

He is a member of APBEES. His area of research is in CAD/CAM/CAE-Applications in Agricultural Engg.and Food engg.,Farm machiney and power,Agricultural process Engg.,Mechanization in Agriculture.

Shyam R. Kajale was born on 1959 in Mharashtra State, India. He completed his bachelor of Engineering on Mechanical Engineering in 1983 from Nagpur University. He is Master’s degree in Mechanical Engineering and the Docterate degree in Mechanical Engg. from IIT Kharagpur (W.B.)India. He is Currently Working as a Director, Shri Guru Gobind Singhji Institute of Engineering and Technology, Vishnupuri, Nanded (M.S.). He published more than

40 research papers and his area of Research is in Micro and on-Conventional Manufacturing, CAD/CAM, Process Modelling and Optimisation.


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design optimization in rotary tillage tool system

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