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Proceedings of Third IRF International Conference on 8th February 2015, Cochin, India, ISBN: 978-93-84209-88-9

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FINITE ELEMENT ANALYSIS OF CONNECTING ROD USING ANSYS

1NIKHIL U.THAKARE, 2NITIN D. BHUSALE, 3RAHUL P.SHINDE, 4MAHESH M.PATIL

1,3,4B.E., Babasaheb Naik College of Engineering, Pusad, Maharashtra, India,2Research Scholar

Abstract- Connecting rod is the intermediate link between the piston and the crank. And is responsible to transmit the push

and pull from the piston pin to crank pin, thus converting the reciprocating motion of the piston to rotary motion of thecrank. Generally connecting rods are manufactured using carbon steel and in recent days aluminium alloys are finding itsapplication in connecting rod. In this work connecting rod is replaced by aluminium based composite material reinforcedwith silicon carbide and fly ash. And it also describes the modeling and analysis of connecting rod. FEA analysis was carriedout by considering two materials of connecting rod for 180cc engine. The parameters like von misses stress and

displacement were obtained from ANSYS software. Compared to the former material the new material foundto have lessweight and better stiffness. It resulted in reduction of 39.48% of weight, with 64.23%reduction in displacement.

Keywords- Connecting Rod, Ansys, Composite, Silicon Carbide, Fly Ash, Analysis

I. INTRODUCTION

Connecting rod is the intermediate link between the piston and the crank. And is responsible to transmitthe push anpull from the piston pin to crank pin, thusconverting the reciprocating motion of the piston to

rotary motion of thecrank. Connecting rod,automotives should be lighter and lighter, should

consume less fuel and at the same time theyshould provide comfort and safety to passengers, thatunfortunately leads to increase in weight of the

vehicle. Thistendency in vehicle construction led theinvention and implementation of quite new materialswhich are light and meet design requirements. Lighter

connecting rods help to decrease lead caused byforces of inertia in engine as it does not require big balancing weight on crankshaft. Application of metal

matrix composite enables safety increase andadvances that leads to effective use of fuel and toobtain high engine power. Honda Company had

already started the manufacturing of aluminumconnecting rods reinforced with steel continuousfibers. By carrying out these modifications to engine

elements will result in effective reduction of weight,increase of durability of particular part, will lead todecrease of overall engine weight, improvement in its

traction parameters, economy and ecologicalconditions such as reduction in fuel consumption andemission of harmful substances into atmosphere.

K. Sudershankumar et al, described modeling andanalysis of Connecting rod. In his project carbonsteelconnecting rod is replaced by aluminium boron

carbide connecting rod. Aluminium boron carbide isfound to haveworking factory of safety is nearer totheoretical factory of safety, to increase the stiffness

by 48.55% and to reducestress by 7.84%.

Vivek. C. Pathade et al, he dealt with the stress

analysis of connecting rod by finite element methodusing pro-ewild fire 4.0 and ansys work bench 11.0software. And concluded that the stress induced in the

small end of theconnecting rod are greater than thestresses induced at the bigger end, therefore the

chances of failure of the connectingrod may be at thefillet section of both end.

Pushpendrakumar Sharma et al, performed the static

FEA of the connecting rod using the software andsaidoptimization was performed to reduce weight.

Weight can be reduced by changing the material ofthe current forgedsteel connecting rod to crackableforged steel (C70). And the software gives a view of

stress distribution in the wholeconnecting rod whichgives the information that which parts are to behardened or given attention during manufacturing

stage.

Ram bansal et al, in his paper a dynamic simulation

was conducted on a connecting rod made ofaluminium alloyusing FEA. In this analysis ofconnecting rod were performed under dynamic load

for stress analysis and optimization.Dynamic loadanalysis was performed to determine the in serviceloading of the connecting rod anFEA was conducted

to find the stress at critical locations.

II. THEOROTICAL CALCULATION OF

CONNECTIG ROD

1.Pressure calculation :

Consider a 180cc engineEngine type air cooled 4-stroke

Bore × Stroke(mm) = 63.5×56.4

Displacement=178.6 cm Maximum Power = 17.03bhp at 8500rpmMaximum torque= 14.72 Nm at 6500rpm

Compression Ratio=9.38/1Density of petrol at 288.855 K - 737.22*10-9

kg/mm3Molecular weight M - 114.228 g/moleIdeal gas constant R – 8.3143 J/mol.k

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Finite Element Analysis of Connecting Rod Using Ansys

Proceedings of Third IRF International Conference on 8 th February 2015, Cochin, India, ISBN: 978-93-84209-88-9

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From gas equation,PV=m. Rspecific. TWhere, P = Pressure

V = Volumem = MassRspecific= Specific gas constant

T = TemperatureBut, mass = density * volumem =737.22E-9*180E3

m = 0.1326 kgRspecific= R/MRspecific= 8.3143/0.1326

Rspecific= 62.702P = m.Rspecific.T/VP = 0.1326*62.702*288.85/180E3

P = 13.34MPaP ~ 13 MPA.2. Design Calculation of connecting rod:

In general

Fig.1: I Section for connecting rod

From standards,

Thickness of flange and web of the section = tWidth of the section B = 4tHeight of the section H = 5t

Area of the section A = 11t Moment of inertia about x axis Ixx= 34.91t4Moment of inertia about y axis Iyy= 10.91t4Therefore Ixx/Iyy= 3.2

So, in the case of this section (assumed section) proportions shown above will be satisfactory.

Length of the connecting rod (L) = 2 times the strokeL = 56 mm

Fp= (d2/4) * gas pressureFp= 38003.56 N

WB = FC × F. S.= 38003.06×1.78 = 95007.65 N

We know that radius of gyration of the section aboutX-axis,

Kxx= = .

= 1.78 t

Radius of crank,

r =

= = 28 mm

Length of Connecting Rod = 2×stroke=2×56=112mm

Equivalent length of the connecting rod for bothends hinged, L= l = 112 mm1.For AL360 MATERIAL

Now according to Rankine’s formula, we know that

buckling load (WB),95007.65=

×

= 5.13 mm (α =0.002)

Thus, the dimensions of I-section of the connecting

rod are:Thickness of flange and web of the section = t =5.13mm Width of the section, B = 4 t = 4 × 5.13 =20.52mm Height of the section,H = 5 t = 5 × 5.13 = 25.63

mm Depth near the big end,H1 = 1.2H = 1.2 × 25.65= 30.78 mmand depth near the small end,

H2 = 0.85H = 0.85 × 25.65 = 21.80 mm

2.ForAluminium 6061-9%Sic-15%Fly Ash

30187.6=∗

= 3.82 mm

Width of the section, B = 4 t = 4 × 3.82 =15.28 mmHeight of the section,H = 5 t = 5 × 3.82 = 19.1 mmDepth near the big end,

H1 = 1.2H = 1.2 × 25.65= 16.235 mmdepth near the small end,H2 = 0.85H = 0.85 × 25.65 = 22.92 mm

TABLE 1MATERIAL PROPERTIES USED FOR ANALYSIS

III. FEA OF CONNECTING ROD

Fig 2. Model of connecting rod

Fig 3. Meshed model of connecting rod

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Fig 4. All DOF constrained at crank end

Fig 5. Tensile load applied at piston end

Fig 6. Compressive load applied at piston end

IV. RESULTS AND DISCUSSION

ANALYSISFor the finite element analysis, 13MPa of pressure isused. The analysis is carried out using ANSYS

software. The pressure is applied at the small end ofconnecting rod keeping big end fixed. Themaximum and minimum von-misses stress,displacement are noted from ANSYS.

TABLE 2COMPARISON OF STRESS AND DISPlACEMENT FOR DIFFERENT MATERIALS

Sr

no

Material Tensile load Compressive load

Stress(MPa)

Displacement(mm)

Stress(MPa)

Displacement(mm)

1 Old material 79.637 0.0349 42.882 0.059

2 AL6061-9%SiC-15% fly ash

114.17 0.123 60.019 0.0214

3 percentage 43.36 64.75 39.96 63.72

1.VON-MISES STRESS PLOTS:

Fig 7. Von-mises stress for tensile load Al-360

Fig 8.Von mises stress for tensile load,ALFASiC

From fig 7.the maximum stress occurs at the pistonend of the connecting rod is 79.637 Mpa. From thefig 8 the maximum stress occurs at the pistonend ofthe connecting rod is 114.17 Mpa.

Fig 9.Von-Mises Stress For Compressive Load,Al360

Fig 10.Von mises stress for compressrive load, ALFASiC

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From fig 9.the maximum stress occurs at the pistonend of the connecting rod is 42.882 Mpa. From thefig 10 the maximum stress occurs at the pistonend of

the connecting rod is 60.019 Mpa.

2.DISPLACEMENT PLOTS

Fig 11.Displacement For Tensile Load Al-360

Fig 12.Displacement For Tensile Load ALFASiC

From the fig 11 the maximum displacement occurs inthe connecting rod is 0.0349 mm. From the fig 12 the

maximum displacement occurs in the connecting rodis 0. 0123 mm.

Fig 13. Displacement For Compression Load Al-360

Fig 14. Displacement For Compression Load, , ALFASiC

From the fig 13 the maximum displacement occurs inthe connecting rod is 0. 059 mm. From the fig 14 themaximum displacement occurs in the connecting rod

is 0. 0214 mm.

3. VOLUME, WEIGHT AND STIFFNESS OF THE

CONNECTING ROD.a) Weight of the Connecting Rod.For aluminium 360:

The volume of the connecting rod used is 137650

mm. Therefore the mass of the connecting rod forrespective materials are:

Weight = volume * densityWeight = 137650 *2.8e-3Weight = 385.42 grams

For aluminium 6061-9%SiC-15%fly ashThe volume of the connecting rod used is

89306.72mm. Therefore the mass of the connectingrod for respectivematerials are:Weight = volume * density

Weight = 89306.72* 2.61161e-3=233.233 gramsTherefore there is net difference of 152.19 grams inthe new connecting rod for the same volume, i.e., is

39.48 % reduction in weight.

b) Stiffness of the Connecting Rod

1.Foraluminium 360Weight of the connecting rod = 385.42gramsDeformation = 0.0349 mm

Stiffness = weight / deformation

Stiffness = 385.42/0.0349Stiffness = 11043.55 g/mm

1.Foraluminium 6061-9%SiC-15%fly ashWeight of the connecting rod = 233.233grams

Deformation = 0.0123 mmStiffness = weight / deformationStiffness = 233.233/0.0123

Stiffness = 18962.03 g/mm

CONCLUSION

Weight can be reduced by changing the material of

the current al360 connecting rod to hybridAlfasic composites. the optimised connecting rod is 39.48% lighterthan the current connecting rod.

the new optimised connecting rod is comparativelymuch stiffer than the former.

REFERENCES

[1] K. Sudershan Kumar, Dr. k. Tirupathi Reddy, Syed

AltafHussan “Modeling and analysis of two Wheeler

connecting rod”, International Journal of Modern

Engineering Research, Vol -2, Issue- 5, pp-3367-3371, Sep-

Oct-2012.

[2] Vivek.c.pathade, BhumeshwarPatle, Ajay N. Ingale ”Stress

Analysis of I.C. Engine Connecting Rod by FEM”,

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