Rediseño de Eje Tractor en Ansys

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REDESIGNING OF TRACTOR

TROLLEY AXLE USING ANSYS

Harish V. KatoreP.G CAD / CAM student

Department of Mechanical Engineering,G. H. Raisoni College of Engineering, Nagpur

E-mail- [email protected]

Prof. Santosh B. JajuDepartment of Mechanical Engineering,

G. H. Raisoni College of Engineering, NagpurE-mail- [email protected]

Abstract-In Central India, various small scale industries are adopting the crude methodologies for designing &manufacturing the machine components. One such industry producing tractor trolleys for agricultural use hasbeen identified for this study. The existing trolley designed by the industry uses heavy axle without consideringstatic and dynamic loading conditions which in turn leads to higher factor of safety increasing the overall cost ofthe axle. In this study, existing trolley axle is redesigned considering the static and dynamic load conditions. A

CAD model is prepared using CATIA V5 as a tool. Minimum cross section for the axle is calculated whichresulted in the 24.8 % reduction in the weight of the axle. The axle dimensions are redesigned to 75 X 75 mmwhich is comparatively smaller than the old axle. The design is optimized based on the manufacturing cost ofthe axle. The failure analysis is performed on the axle of trolley used in agricultural area. These results provide atechnical basis to prevent future damage to the location axle.

Keywords: Axle design, CAD modeling, optimization, stress analysis

1. INTRODUCTIONIn the present market scenario, cost reduction technique is playing signified role to meet the

competition in the market. Weight reduction and simplicity in design are application of industrial engineering

etc., the sources of the technique which are used.

Various components or products used in rural areas are mostly manufactured in small scale industriessuch as farming machinery, thrashers, tractor trolleys etc. It has been observed that these rural products are notproperly designed. These products are manufactured as per need, by trial and error methods of manufacturing.Big industrial sectors have not yet entered in manufacturing of these products; hence no significant development

in design of rural product has been done so far. Thus most of rural products are manufactured withoutavailability of design. Tractor trolleys are manufactured in small to moderate scale industries. Through tractortrolleys are manufactured of various capacities by various industries, still there is a large vibration inmanufacturing methods, component design etc. The trolley axle manufacturers are having no proper design oftrolley, through these trolleys are to be certified by R.T.O. authority. It is observed that most of the trolleys are

design for static conditions by tacking large factor of safety.Local Industries in MIDC, Wardha, is presently the leading manufacturers of tractor trolleys producing

about 2000 trolleys per annum. The analysis and discussion with owner of local Industries in MIDC, Wardha,revealed that with proper design approach the cost of trolley axle can be reduced. As there is lot of competitionin the market, reduction in cost is necessary.

2. TYPES OF LOADThe trolley chassis main frame is supported at two points over the axle. The chassis is connected to

wheel axle through isolator leaf spring and to the tractor coupling. The leaf spring attached to main frame and to

the axle at two points and this leaf spring transfer the total load to the axle.

2.1. STATIC LOAD ON AXLE

The static load on axle is calculated by considering the fully loaded trolley model. The load diagramconsists of the total load of load model and weight of axle. Considering the model, fully filled trolley, here the

Harish V. Katore et al. / International Journal of Engineering Science and Technology (IJEST)


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trolley is loaded with total capacity including axle assembly of 73 KN. Thus the total weight of trolley isdistributed and has been considered in same manner for fully loaded trolley model. As the leaf spring is used asisolator so point load conditions are considered, and the shear force and bending moment diagram are drawn.The procedure adopted for construction of shear force and bending moment diagram is as per following:

1. Determination of reaction at support.2. Determination of value of shear force at change of load position.3. Sketch the shear force diagram.4. Determination of values of bending moment at change of load point.5. Sketch the bending moment diagram.

2.2.DYNAMIC LOAD

Trolleys are used in rural areas and on rough roads at moderate speed i.e. up to 40 km per hour. On fullload conditions the speed is 20 km per hour maximum. Due to moderate speed and wavy road conditions theaxle is subjected to dynamic loads which are nonlinear in nature. The load coming on the axle due to this aremuch larger than static loads, which makes it necessary to analyses the axle for dynamic loads. The shocks dueto sudden velocity change may cause impact loading. The isolators are must for reducing such a high impactwhich may be the cause for failure. All these conditions have been considered while preparing its dynamic load

model.

3. STATIC LOAD ANALYSISThe total capacity of the trolley is 60 KN but self weight of trolley and the axle assembly is 13 KN. So

we consider the gross weight come over the axle is 73 KN. As the leaf spring is used as the isolator and wholeweight of the trolley is mounted over there. Due to leaf spring the total weight of the trolley is transferred over

the axle at two point C and E as shown in load distribution diagram.

Table 1. Specification of 6-tonne 2-wheeler trolley

GeneralSingle axle, 2-wheeler box type

trolley

Overall

dimensions

Overalllength

3100mm (trolley box)4025mm (chassis )

Overallwidth

1900mm (trolley box)

Overallheight

730mm (trolley box)1700mm above ground

Load

capacity

Pay load 60KN

Unloaded

weight13KN

Grossload

weight

73KN

Axle

One square axle is used presently75*75 mm square of length 1700mm.

Weight of axle assembly 0.75KN

TiresTwo no. of

9 ( width ) X 20 ( radius )

Fig. No. 3.1 Load diagram



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The axle having the wheel support at point A and B, so reactions are comes at point A and B and it comes to be_RA = 36.88 KNRB = 36.87 KN

4. SHEAR FORCE AND BENDING MOMENT ON AXLEThe shear force and bending moment at points A, B, C, D, E on the axle are found to be_

Table 2. Values for shear force and bending moment

5. DESIGN OF AXLEAn axle is a stationary machine element and is used for the transmission of bending moment only. It simply act

as a support for some rotating body such as hoisting drum and in tractor trolley case the axle is supporting ofrotating member known as hub for holding the tires.

So the axles are used to transmit bending moment only. Thus axles are designed on the basis ofbending moment only.

When the axle is subjected to a bending moment only then we get the following data_* Moment of inertia of cross sectional area of the axle about the axis of rotation (I) is equal to 2636718.75 mm4

* As we selected the material for axle is SAE 1040 having bending stress (fb) (allowable) is 430 MPa.

* Bending moment is found to be 30234375 N mm

On the observations of the bending moment we found that When the axle length and the point load applied on it is considered then the maximum bending stress is foundequal to 5899.85KN mm. When the material is considered and the cross sectional area is considered then the maximum bending momentis found equal to 30234.375 KN mm.

As the axle is not affected by the length because length between two tires is same, so it will not be

change. We considered the maximum bending moment is 30234.375 KN mm which is related to the crosssectional area of the square bar axle.The section modulus (z) of the existing axle (75 X 75 X 1700 mm) is found to be 70.31 X 10

3 mm3 as z = M / fb.

We cross check this section modulus by using data book formulae_Section modulus (z) = b3 / 6 = 70.31 X 103 mm3.So it is conform that the section modulus of the existing axle is 70.31 X 10

3mm

3.

The axle self weigh approximately 0.75 KN. The maximum load on the axle is 36.5 KN. The figure shows the

loading diagram for axle.Fig No. 5.1 LOAD DIAGRAM OF AXLE

The maximum moment = 5899.85 KN mm

The bending stress (allowable) = 430 MPa (SAE 1045)Section modulus (z) = M / fb = 13.72 X 10

3 mm3

In the existing trolley the square axle of 75 mm X 75 mm of length 1700 mm is used,Having section modulus (z) = 70.31 10

3mm

3.

The obtained value of z = 13.72 X 103mm

3= b

3/ 6 = 43.50 mm = 45 mm.

Load Point Shear Force Bending Moment

A 36.87 KN 0 KN mm

C 0.37 KN 5714.85 KN mm

D -0.38 KN 5899.85 KN mm

E -36.88 KN 5709.85 KN mm

B 0 KN 0 KN mm



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Thus the presently used axle can be replaced by the suggested square axle of 45 mm X 45 mm asshown in figure5.2, but it required the modification in present hub dimensions.

The other alternative suggested is combination of hollow square shaft with solid square shaft as shownin figure5.3. The hollow square shaft is of 90 mm X 90 mm and inside square of shaft is of 75 mm X 75 mm

having length 1300 mm. The section modulus (z) is found to be 64 X 103

mm3

and the solid square shaft of 75mm X 75 mm of length 800 mm having section modulus (z) = 70.31 X 103 mm3.

Fig No. 5.2 SOLID AXLE

Fig No. 5.3 COBINATION AXLE

The approximate weight of combination axle is 0.55 KN. The combination axle can be made by cuttingsolid shaft of 400 mm, and then the both piece of 400 mm shaft is machined to shape from one side as per

fitment of hub. The inside width of hallow square shaft is 75.5 mm. and then solid axle is inserted into hollowshaft and then welded.

6. CHECK FOR BENDING STRENGTHThe combination axle has to be checked for the developed bending stress due to load of 36.5 KN.

fb developed = M / zM max = 20340 KN mm

Z = 64 X 103 mm3

fb = 317.81 N / mm2

The bending stress is less than the permissible value hence combination axle is safe.

7. THE SPECIFICATION OF SUGGESTED COMBINATION AXLE 75 mm X 75 mm square shaft

0.800 mtr 34 kg

Weight 44.2 kg / mtr

Z = 70.31 x 103

mm3

Hollow shaft 90mm X 90mm x 8 mm1.100 mtr 22.4 kg

Weight 20.4 kg / mtr

Z = 64 X 103 mm3

The total weight of combination axle56.4 kg



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Table 3. Comparison between existing axle and proposed axle

Sr. No. Existing Axle Proposed Axle

1. Material selected

SAE 1045

Material selected

SAE 1045

2. Section modulus

70.31X103mm3

Section modulus

64X103 mm3

3. Considering

available

bending stress

430 MPa

Calculating bending

stress

317.81 MPa

4. Weight

75 Kg

Weight

Hollow-26.52 Kg

Solid Shaft- 34 Kg

Total- 60.52Kg

8. STRESS ANALYSIS USING ANSYS TOOL

The above suggested combination axle is safe or not, also proved by using ANSYS. The following are the

images for existing axle from industry shows the equivalent (von-mises) stress, equivalent strain, total

deformation and factor of safety.

Solid axle geometry is generated in ANSYS and get the stress, strain, total deformation, and factor of

safety by using the steps given bellow also figure shows the color effect which shows effect of load on the axle.

STEPS

Modelo Geometry

Part 1o Mesho

Static Structural Analysis Settings Loads Solution

Solution Information Results Stress Tool

Results8.1 ANALYSIS OF EXISTING AXLE IN ANSYSFigure 8.1.1 shows the solid geometry in ANSYS, any 3D modeling software (such as CATIA V5, PRO-

ENGINEERING) geometry in IGS from open in ANSYS.

FIG 8.1.1 SOLID AXLE



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Figure 8.1.2 shows the Equivalent (von-mises) stress on the axle when the load is applied. Red color shows the

maximum stress and blue color shows minimum stress generated on the axle.

FIG.8.1.2 EQUIVALENT (VON-MISES) STRESS

Figure 8.1.3 shows the Equivalent strain on the axle when the load is applied. Red color shows the maximum

strain and blue color shows minimum strain generated on the axle.

FIG.8.1.3 EQUIVALENT STRAIN

Figure 8.1.4 shows the Total deformation of axle when the load is applied. Red color shows the maximum

deformation occurs on the axle and blue color shows the minimum deformation on the axle.

FIG.8.1.4 TOTAL DEFORMATION

Figure 8.1.5 shows the factor of safety of axle when the load is applied. blue color shows the maximum factor of

safety occurs on the axle and Red color shows the minimum factor of safety on the axle.



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FIG 8.1.5 FACTOR OF SAFETY

8.2 ANALYSIS OF EXISTING AXLE BY USING ANSYS

Sr.

No.

Factors Values

1. Equivalent Stress 6.3799 MPa2. Equivalent Strain 3.19 X10

-5m/m

3. Total Deformation 2.335 X 10-5

m

4. Factor of Safety 15

5. Mass 69.088 Kg

8.3 ANALYSIS FOR SUGGESTED AXLE (COMBINATION AXLE)

Figure 8.3.1 shows the combination axle geometry in ANSYS, figure shows the one hollow shaft and two pieces

of solid axle.FIG 8.3.1 COMBINATION AXLE

Figure 8.3.2 shows the Equivalent (von-mises) stress on the axle when the load is applied. Red color shows the

maximum stress and blue color shows minimum stress generated on the axle.

FIG 8.3.2 EQUIVALENT STRESS

Figure 8.3.3 shows the Equivalent strain on the axle when the load is applied. Red color shows the maximumstrain and blue color shows minimum strain generated on the axle.



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FIG 8.3.3 EQUIVALENT STRAIN

Figure 8.3.4 shows the Total deformation of axle when the load is applied. Red color shows the maximum

deformation occurs on the axle and blue color shows the minimum deformation on the axle.

FIG 8.3.4 TOTAL DEFORMATION

Figure 8.3.5 shows the factor of safety of axle when the load is applied. blue color shows the maximum factor of

safety occurs on the axle and Red color shows the minimum factor of safety on the axle.

FIG 8.3.5 FACTOR OF SAFETY

8.4 ANALYSIS OF COMBINATION AXLE BY USING ANSYS

Sr.No. Factors Values

1. Equivalent Stress 11.168 MPa

2. Equivalent Strain 5.5841 X10-5 m/m

3. Total Deformation 1.3565 X 10-5 m

4. Factor of Safety 15

5. Mass 53.301 Kg



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9. COMPARISON BETWEEN EXISTING AXLE AND PROPOSED AXLE USING ANSYS

Sr.

No.Existing Axle Proposed Axle

1. Equivalent Stress =

6.3799 MPa

Equivalent Stress

=11.168 MPa2. Equivalent Strain

= 3.19X10-5

m/m

Equivalent Strain

=5.5841X10-5

m/m

3. Total Deformation

=2.335 X 10-5

m

Total Deformation

=1.3565 X 10-5

m

4. Factor of Safety =15 Factor of Safety =15

5. Mass

=69.088 Kg

Mass

=53.301 Kg

10. CONCLUSIONThe dimension of the existing axle is change to be reduced as it proved by above, but there is assembly problemin hub on the axle as the dimensions of the axle is change. As the dimensions are reduced, the assembly problem

is occurred so other solution is given as the hollow shaft, which exist the earlier dimensions for the hubassembly on the newly designed axle.

This newly designed axle reduces the 22.85% weight as compare to the existing axle shown incomparison table. Also reduces in the cost of trolley axle as the weight of the axle reduces. The weight of axle isreduced without compromising with existing hub assembly of wheel, factor of safety and stiffness of the axle.

11. REFERENCES[1] Narang B.S. Automobile Engineering, Khanna Publication[2] Arya A.S., Ajamani J.I., Design of steel Structure[3] Balaney P.L. Theory of machine, Khanna Publisher[4] Shigley J.E., Mechanical engineering design, McGraw-Hill[5] Singer F. L., Engineering mechanics static and dynamic, Harper Collins.[6] Shiwalkar B.D., Design data for machine element, central Techno Pbl.[7] Malcolm K.G., B.A. Stout and S.W. Searcy. 1985. Instrumentation package for monitoring tractor performance.[8] Transactions of the ASAE 28(2): 346-349, 355.[9] J. Pierowicz, National advanced driving simulator utilization research.[10] M.K. Salaani, G.J. Heydinger Heavy Tractor-Trailer Vehicle Dynamic Modeling.[11] W. R. Garrott, P. A. Grygier Methodology for validating the national advanced driving simulators vehicle[12] dynamics.[13] R.S. Khurmi Strength of material.[14] R.S. Khurmi and Gupta Theory of Machine.



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Rediseño de Eje Tractor en Ansys

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