advancement in simulation of front axle of tractor · mitsubishi tractor to mount on the tractor is...

Sr no Sun Planet Ring Speed Torque 1 Fixed Driving Driven Increase Decrease 2 Fixed Driven Driving Decrease Increase 3 Driving Fixed Driven Decrease Increase 4 Driven Fixed Driving Increase Decreased 5 Driving Driven Fixed Decrease Increase 6 Driven D riving Fixed Increase Decrease

Advancement in Simulation of Front Axle of Tractor

Shantanu Ramesh Shinde Dept:Mechanical Stes’s Skncoe,

Wadgaon(Bk), Pune.

Abstract:- The past few decades have witnessed rapid technological growth in the area of automobiles. One way of improving ones status in market is to keep the products price as low as possible, but with good reliability. This can be done by using CAE tools like FEA. FEA reduces the cost of testing. Previously the analysis of front axle was done without assembling the wheel hub, so the correlation of FEA results with experimental results was about 14-17%. After lots of study it was predicted that if the wheel-hub is assembled with the front axle and the forces are applied on the wheel- hub, the results would be closer to the original values. The objective of this paper is to perform finite element analysis to the front axle system of tractor with wheel-hub for Bump test and Endurance structural test- forward (EST-FWD), Endurance structural test- reverse (EST-REV) to these two test load conditions and validation within 10% of actual stress measured experimentally.

1.0 INTRODUCTION:

Axle is a structural part of tractor which supports the structural load of the tractor and requires adequate design as this component experiences the worst loading condition of the whole tractor. Front axle system consist of axle beam, trunion support, differential support, wheel-hub, steering system i.e., steering cylinder, tie rod and swivel housing etc. will be the major components of axle assembly. Primary function of the axle is to support the weight of the tractor, to transmit the power to the wheels, and to steer the wheels. Axles are broadly classified as:

Axles can also be classified as: 1. Monolithic beam axle 2. Modular axle

In Monolithic type axle there is a single beam with central differential support unit. This Differential support unit is to hold the differential components. Where as in modular type axle there is three different parts which comprises of a center body housing and LHS & RHS trumpets.

1.1 FUNCTIONS OF FRONT AXLE IN A

TRACTOR:-

It supports the weight of front part of the tractor.

It facilitates steering. It absorbs the shocks due undulated road surface. It absorbs the torque applied on it due to braking of

vehicle.

1.2 HOW DOES A TRACTOR’S FRONT AXLE

DIFFER FROM OTHER ROAD VEHICLE’S AXLE:-

The word ‘tract’ means to pull. Hence the word ‘tractor’ means something that pulls. Hence to propel forward against its self-weight and to pull the loaded trailer, large torque is required on wheels. This can be done by either increasing the reduction ratio of the gearbox or increasing the axle ratio. But increasing the reduction ratio will lead to increase in the size of the gearbox and make it bulky and increasing the axle ratio would make the differential housing heavy and bulky. Hence to achieve higher final reduction, a planetary gear set is installed at the end of the swivel housing. Following table shows the possible speed ratios obtained in an planetary gear set:-

In our case, the Sun gear is driving, the planetary gears are driven and the ring gear is fixed. Hence we get Forward very slow speed at the end of the output, with a very high torque.

International Journal of Engineering Research & Technology (IJERT)

ISSN: 2278-0181

www.ijert.orgIJERTV4IS030725

(This work is licensed under a Creative Commons Attribution 4.0 International License.)

Vol. 4 Issue 03, March-2015

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1.3 LITERATURE SURVEY

Dilip K Mahanty et.al, [1] aim of his study to analyse the newly designed front axle of tractor for 13 different certified test loading conditions and results from this study were taken for comparison purpose for proposed models. And based on FEA results redesigned of this model were done to optimise weight of front axle and for ease for manufacturing. They conclude that results shows that this model structure is safe except some localized stress are high. FEA of this model indicates that stresses and displacements are near to existing design.

Majid Khanali et.al [2] carried out FE analysis and redesign

was done to reduce cost, increase mechanical strength, and for easy manufacturing. They carried out static, transient and modal analysis of front axle and results shows that proposed model is suitable to load or install on modified combine.Von misses stress was 72 % of the yielding point of the material and the factor of safety is also low than required author conclude that front axle of JD 955 under maximum loading conditions not satisfying safety conditions and this design need to be optimize to load on modified combine.

Andrei A. Mazhei et.al [3] analysed a possibility of using a tractor front axle hydro-pneumatic suspension through automatic level control and single-acting cylinders. Considering higher vertical loads at tractor driving modes reduction of vibration levels was observed. In addition, by considering front load they observed comfortness of driver is well dependent on the damping in the suspension and the chance of hitting bump stops. Concluded that the results shows that using single- acting cylinders with an automatic level control a suspension does not verify and does not show a constant enhancement in steering response of the tractor and vibration safety.

Osman Asi [4] analysed the failure analysis of the rear axle of automobile. The analysis had been carried to well define the cause of the accident of the failure of the rear axle. He concluded that fatigue was the main cause of the failure as results shown by fractographic study and he verified that cracks were generated from the welded areas. Analytical results shows that because of the improper welding the axle shaft fractured in reverse bending fatigue. Hence he concluded that the fracture was the cause of an accident. Javad Tarighi et.al [5] they analysed front axle housing of MT250D Mitsubishi Tractor. To do other than agricultural work they added, a front mounted mechanical shovel and they observed the stresses. And author conclude that from the finite element analysis result the maximum stresses occurred is on the upper housing and the factor of the safety was obtained which is less than the required value and hence they came to one point that axle housing of MT250D Mitsubishi Tractor to mount on the tractor is not enough strong. And there is a need to redesign the existing model.

N. León et.al [6] they reduced weight of the front axle

beam by following experimental method and the results obtained had co-related with the FEA to validate. Main objective of their study is to reduce material and manufacturing cost.FEA used for to reducing the development time and to increase the product quality. They conclude that proposed development process proved to be useful in maintain the product quality and reliability while reducing the development cost and time. [6] A. K. Acharya et.al [7] analysed Failure Analysis of Rear

Axle of a Tractor with Loaded Trolley for the haulage operation and the analysis had been used with the help of principles of mechanics and they conclude that main cause behind the problem is the weight transfer from front to rear and as remedy reduction of weight is considered. Arun Mahajan et.al [8] carried out Weight Optimization of Front Axle Support by OptiStruct Technology Application and to extract displacement and stresses they done baseline analysis of total front axle assembly and for good material distribution topology optimization had been done. And they conclude that by using HYPERWORKS optimization software the weight of front axle support is reduced by 12% without affecting the strength and with 50% of design cycle time. Axle is designed and analysed for dynamic and static loading conditions and concluded that the weight of the axle is reduced without compromising assembly of axle and as it increases factor of safety hence there is need to redesign of axle and they observed vibration characteristic of axle.[9- 14] Rear axle is observed for vibration levels and also evaluates FOS for rear axle housing of composite material and compared with monolithic metal and results shows that composite material results were good that monolithic metal.[15-19]


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1.4 PROBLEM STATEMENT

Objective of the study is to perform finite element analysis to the front axle system of tractor with wheel-hub for Bump test and Endurance structural test- forward (EST-FWD), Endurance structural test- reverse (EST-REV) to these two test load conditions, validation within 10% of actual stress measured experimentally. It has been reviewed that the high stresses are likely to be occurred in the axle beam hence it is selected as the important part to analysis. In this analysis the front axle is analyzed by only two test load condition as follows: 1. Bump test (BT) 2. Endurance structural test- forward (EST-FWD)

Endurance structural test- reverse (EST-REV)

1.5 GEOMETRIC MODEL OF THE FRONT AXLE

SYSTEM CAD model of the front axle system is modeled separately using commercially available modeling tool (Pro-E).And assembled them together for the work. Some parts are changed as per the dimensions required for the analysis like bearing of the trunion, bearing of the king pin, and bearing of the swivel housing.

1.6 MESHING GENERATION AND CAE

MODEL CAD model, before importing to the analysis tool it is de- featured properly. De-featuring means to suppress the feature that don’t have global effect in the result of analysis, like numbers and codes of fusion, cosmetic features, oil fillers cap holes, holes to fix the flanges, chamfers etc. The mesh is done on the solid model by using analysis tool (NX- NASTRAN). CTETRA(4) elements, used for axle beam, trunion support, wheel-hub and differential support; each of which has four nodes and twelve degrees of freedom and CBEAM 1-D elements, used for steering cylinder and tie rods; each of which has two nodes and twelve degrees of freedom are used in the finite element discretization. Meshing is done separately for each part.

A. ELEMENT TYPE: Element type used for the meshing is 4 node tetrahedral element and 2 node beam RBE2 element.

B. ELEMENT SIZE:

The element size used for the simulation, for 2D mesh 0.5 mm and for 3D mesh 8 mm size is used. Total number of elements generated was 777495.

C. BOUNDARY CONDITIONS AND LOADS

I. Fixed Constrain: This axle is trunion mounted axle, on the trunion; chassis is fixed hence the fixed constrain is applied on the trunion mounted surface. All degrees of freedom are restrained for this condition. The nodes on the fixed boundary cannot move: translation or rotation.

II. Symmetry Constrain: The front axle system model is same from its mid-plane hence to reduce simulation time Symmetry constrain is applied on cutting- plane of the front axle system.

III. Contact Type: The contacts used in the analysis are surface to surface contacts and glue contacts. Glue contact is used between differential support and beam. Surface interaction is used to define the coefficient of friction between the different parts and its bearings. Total 14 surface to surface contacts had been used in this analysis and one glue contact had been used as mentioned above.

IV. Analysis Approach: Dynamic explicit algorithm is the main solution procedure for the simulation of the front axle system. Three dimensional finite element method is developed for the front axle system. This FE procedure does not suffer from convergence problems. By taking the advantage of the symmetry, reduced the time for the solution. The input data for the Finite Element Analysis of Front Axle System is as follows:

Input Data Value

Load 24000 N

Torque at Wheel 9000 Nm

Reference Track 1115mm

Wheel Radius 435 mm

Load: This is the load on the axle that is equivalent to the division of the vehicle’s weight in accordance with the various work configurations. This load allows the vehicle to travel up to this maximum speed. Reference Track: This is the track or distance to which the load bearing capacity is applied.

1.Endurance structural test : Endurance structural test is carried out by fixing the tyres of the axle and the load is applied.

Fig1.1 : Endurance structural test-forward (EST-FWD)


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Load

Component

EST_FWD

(N)

EST _REV

(N)

BT

(N)

fx 9933 -9933 0

fy 0 0 0

fz 18000 18000 42000

Two loads will be considered here vertical and horizontal. The load is converted in to dynamic load by using 1.5 factor of acceleration for EST load case. It is checked for 20000 cycles.

Vertical load: vertical action due to contact wheel ground and calculated by

EST_FWD = 24000*1.5/2

= 18000 N

Horizontal load: for horizontal load we need T= F × r ..........where

T = torque r=wheel radius

Fig1.2 Bump Test (BT) Table below gives us the information about directional loads applied for the different load case.

hence, F=T/r

Torque and wheel radius we know as input data from that force will be calculated and that force will be used for this load test. EST_FWD = (9000/2)/0.543

= 9933 N

EST_REV is same in the magnitude as in EST_FWD but in the opposite direction to forward load case.

EST_REV = -9933N

2.Bump test (BT): In this case maximum load is given in the pulsating form and it is checked for 10000 cycles. The input load is converted in to maximum dynamic load by considering 3.5 as acceleration factor and is calculated as,

BUMP TEST = 24000*3.5/2

= 42000 N

1.7 MATERIAL DETAILS EN-GJS 400 represents Spheroidal cast iron and “400” represent tensile strength of cast iron. Cast irons are iron alloys that contain more than 2% carbon and from 1 to 3% silicon. Wide variations in properties can be achieved by varying the balance between carbon and silicon, by alloying with various metallic elements, and by varying melting, casting, and heat treating practices. Spheroidal cast iron also known as nodular iron. All cast irons have in common a microstructure that consists of graphite phases in a matrix. C-43 represents carbon non alloy steel, carbon content is 0.43%. This comes under medium carbon steel. As the percentage of carbon content increases steel has the ability to become stronger and harder. This carbon steel balances the strength and ductility and has good wear resistance. Materials properties used for the analysis is tabulated in the Table shown below:

Parts Material Young’s modulus (MPa)

Poisson’s ratio

Density (tonnes /mm^3)

Tensile strength (MPa)

Beam EN-GJS 400 Spheroidal CI

169000 0.275 7.1 e-09 400


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Front & rear trunion

EN-GJS 500

169000 0.275 7.1 e-09 500

Differential support & swivel housing

EN-GJS 600

1674000 0.275 7.1 e-09 600

Upper & lower king pin

C-43 Steel

180000 0.275 7.8e-09 645

Wheel hub EN-GJS 500

169000 0.275 7.1 e-09 500

Sr.

No.

Load case Max. Stress

(MPa)

Beam Hub

1 EST_FWD 125 27.32

2 EST_REV 175 34.82

3 BT 154 27.16

1.8.1 MAXIMUM PRINCIPAL STRESS FOR ENDURANCE STRUCTURAL TEST-FORWARD LOAD

CASE

1.8 RESULTS OF ANALYSIS

As discussed earlier, from the literature review it was found out that the critical areas where the peak stresses are induced nothing but the beam. And the theory of failure is considered in this study is maximum principal stress theory, which states that maximum value of normal stress, the plane on which maximum principal stress acts and shear stress value is zero. All the sub-component of the front axle system are manufactured by casting process. Hence it’s recommended that for the brittle materials maximum principal stress theory is preferred.

Table below shows that the maximum stresses in the different components for EST load case and BT load case.

Fig1.3 EST FWD - Maximum principle stress plot for complete

assembly

Fig1.4 EST FWD - Maximum principle stress plot for

beam

Fig1.3 shows maximum principal stress plot for complete assembly and beam respectively for endurance structural strength-forward load case. As shown in the fig 1.4 the maximum stresses are developed (125 MPa) in the lower


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side of the beam and the critical area is fillet section of the rib.

1.8.2 MAXIMUM PRINCIPAL STRESS FOR ENDURANCE STRUCTURAL TEST-BACKWARD

LOAD CASE

Fig1.5 EST REV - Maximum principle stress plot for complete assembly

Fig1.6: BT-Maximum principle stress plot for complete assembly

Fig1.5 shows maximum principal stress plot for complete assembly and beam respectively for bump test load case.

As shown in the fig1.6 the maximum stresses are developed (154) MPa in the critical region of the fillet of rib at the bottom side of the axle.

1.8.3 MAXIMUM PRINCIPAL STRESS FOR BUMP TEST (BT) LOAD CASE

Fig1.7 BT-Maximum principle stress plot for beam

Fig1.8 BT-Maximum principle stress plot for complete assembly

Fig1.7 shows maximum principal stress plot for complete assembly and beam respectively for bump test load case. As shown in the fig 1.8 the maximum stresses are developed (154) MPa in the critical region of the fillet of rib at the bottom side of the axle.


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BUMP TEST

EST- FORWARD

EST- REVERSE

Numerical results(MPa)

154 125 175

Experimental results(MPa)

142 140 162

2.0 EXPERIMENTAL VALIDATION

It had been carried out finite element analysis for the front axle system and collected FEA results. But to propose new simulation method validation is important. Hence, Front axle system is tested experimentally. The results were correlated with the FEA results within 10%. The experimental testing is carried out by strain gauging.

Fig2.1 Experimental set-up of Bump Test of Front Axle

2.1 STEPS IN INSTALLING STRAIN GAUGES ON FRONT AXLE SYSTEM:

Careful preparations are necessary for the optimum measurement especially for large measurement tasks. Preparation including planning, material and disposition of personnel. There are steps for installing strain gauges that are follows: The installation person/technician must have information of following :

1. Surface preparation for strain gauge bonded. 2. Location of installation and grid orientation with

respect to specimen (plan of measurement points). 3. Circuit plan and layout of cabling. 4. Selection of Strain gauges . 5. Materials used for mounting of strain gauges.

Fig2.3: Strain gauging location for max stresses

Figs. shows the actual location of peak stresses induced in beam indicated by 1, 2 and 3 numbers. It is useful for locating and installation of strain gauges. 3.0 COMPARISON OF RESULTS ACHIEVED BY

NUMERICALLY AND EXPERIMENTALLY

Table above shows that results of maximum stress in the beam measured by numerically and experimentally. The results of finite element method were verified by experimental methods. In this study, the stresses were measured at three locations as shown in fig 4.5 and 4.6 the stress was measured by strain gauging practices. The results obtained were correlated with FEA results to validate the proposed new simulation method.

4.0COMPARISON BETWEEN THE TWO

METHODS

200

150

100

50

PREVIOUS

NEW

EXPT

0 BUMP TEST

EST

FWD

EST

REV

Fig2.2: Strain gauging location for max stresses

From the above stats it is clear that the results of new method is more in correlation with the experimental results.


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5.0 CONCLUSION The three dimensional finite element analyses is developed for front axle system of tractor with wheel hub for two loading conditions i.e. Bump test and Endurance structural test and following conclusions are drawn.

The peak stresses induced are observed in the

bottom side of beam. The results of analysis showed that the maximum

principal stresses in the beam due to BT, EST_FWD, EST_REV loading conditions are 154, 125 and 175 MPa respectively.

From the strain gauging results it has been observed that the results achieved by numerically are within 10% of the experimental results. Hence the proposed method holds good for the simulation of the front axle system.

ACKNOWLEDGEMENT:

My grateful thanks to MR. SURESH YADAV(sir) & MR. GITESH NARVEKAR(sir), who inspite of being busy with his duties took time out to hear ,guide and keep me on the correct path. MR. NILESH SALMALKAR(sir), monitored my progress and arranged all facilities. I choose this moment to acknowledge his contribution gratefully.

REFERENCES

[1] Dilip K Mahanty, Vikas Manohar, Bhushan S Khomane, Swarnendu

Nayak, Analysis and Weight Reduction of a Tractor’s Front Axle [2] Majid Khanali , Ali Jafari, Hossein Mobli and Ali Rajabipour, (2 0 1

0) Analysis and design optimization of a frontal combine harvester axle using finite element and experimental methods, Journal of Food, Agriculture & Environment Vol.8 (2): 3 5 9 - 3 6 4.

[3] Andrei A. Mazhei, Alexander A. Uspenskiy ,Valery G. Ermalenok, (2006) Dynamic Analysis of the Hydro-Pneumatic Front Axle Suspension of Agriculture Tractor, SAE TECHNICAL PAPER SERIES ,01-3526

[4] Osman Asi, (2006) Fatigue failure of a rear axle shaft of an automobile, Engineering Failure Analysis,13 1293–1302

[5] Javad Tarighi, Seyed Saeid Mohtasebi, Reza Alimardani, (2011) Static and dynamic analysis of front axle housing of tractor using finite element methods, American Journal of Agricultural Economics (AJAE) 2(2):45-49.

[6] N. León , O. Martínez, P. Orta C., P. Adaya, (2000) Reducing the Weight of a Frontal Truck Axle Beam Using Experimental Test Procedures to Fine Tune FEA, 2nd Worldwide MSC Automotive Conference. Dearborn, Michigan; October 9-11.

[7] A. K. Acharya, I. Panigrahi, P. C. Mishra (2013) Failure Analysis Of Rear Axle Of A Tractor With Loaded Trolley, International Journal of Innovative Research and Development, Vol 2 Issue 10, pg.241-243.

[8] Vinod Kumar Verma, Dinesh, Redkar, Arun Mahajan (2012) Weight Optimization of Front Axle Support By OptiStruct Technology Application.

[9] Mulani Nawaj. A & Mirza M. M. (2013) FEA Analysis of Bullock cart Axle under Static and Dynamic Condition, ISSN (Print): 2321-5747, Volume-1, Issue-2.

[10] Shan Shih, Scott Kuan and Dale Eschenburg, (2003) Considerations in the Development of Durability Specifications for Vehicle Drive Train Component Test, SAE International Truck and Bus Meeting and Exhibition Fort Worth, Texas November 10-12, 2003.

[11] Baozhan Lü, Sihong Zhu and Ying Zhang, (2007), Research on Parameter Matching of Front Axle Suspension Vehicle Based on MATLAB, Proceedings of the IEEE International Conference on Automation and Logistics August 18 - 21, 2007, Jinan, China.

[12] Geice Paula Villibor, Fábio Lúcio Santos, Daniel Marçal de Queiroz2 and Denis Medina Guedes, (2014) Vibration levels on rear and front axles of a tractor in agricultural operations, Acta Scientiarum. Technology Maringá, v. 36, n. 1, p. 7-14, Jan.-Mar., 2014.

[13] Happy Bansal1, Sunil Kumar (2012), Weight Reduction and Analysis of Trolley Axle Using Ansys, International Journal of Engineering and Management Research, Vol.-2, Issue-6, December 2012 ISSN No.: 2250-0758 Pages: 32-36.

[14] Sairam Kotari , V.Gopinath (2013) Static And Dynamic Analysis On Tatra Chassis, International Journal of Modern Engineering Research (IJMER), Vol.2, Issue.1, pp-086-094 ISSN: 2249-6645.

[15] Jungang Wu, Siqin Zhang,Qinglong Yang, (2012), Deformation Effect Simulation and Optimization for Double Front Axle Steering Mechanism, 4th International Conference on Computer Modeling and Simulation (ICCMS 2012) IPCSIT vol.22 (2012) © (2012) IACSIT Press, Singapore.

[16] Guruprasad.B.S, Arun.L.R, Mohan.K, (2013), Evaluating Fos For Rear Axle Housing Using Hybrid Aluminium Composites, International Journal of Innovative Research in Science, Engineering and Technology Vol. 2, Issue 6, June 2013.

[17] Yuejun Eugene Lee, Vince Monkaba, (2000), Visteon Axle Driveline Simulation Finite Element Analysis Tool (VADSIM-FEA), Seoul 2000 FISITA World Automotive Congress F2000A429 June 12- 15, 2000, Seoul, Korea.

[18] Per-Anders Hansson,(2001), Working Space Requirement for an Agricultural Tractor Axle Suspension, Biosystems Engineering (2002) 81(1), 57d71.

[19] John E. Baumgras, (1976), Better Load-Weight Distribution Is Needed For Tandem-Axle Logging Trucks, USDA FOREST SERVICE RESEARCH PAPER NE-342.


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advancement in simulation of front axle of tractor · mitsubishi tractor to mount on the tractor is...

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