design evaluation and optimization of connecting rod

21

International Journal of Engineering and Management Research, Vol.-2, Issue-6, December 2012

ISSN No.: 2250-0758

Pages: 21-25

www.ijemr.net

Design Evaluation and Optimization of Connecting Rod Parameters Using

FEM

Suraj Pal1, Sunil kumar

2

1P.G. student, Y.C.O. Engg. Talwandi sabo, Department of Mechanical Engg.

2 Senior Assistant Professor Y.C.O. Engg. Talwandi sabo, Department of Mechanical Engg.

ABSTRACT

The main objective in the “Design evaluation and

optimization of connecting rod parameters by using finite

element method” is to achieve suitable design for connecting

rod. That can be achieved by changing such design

parameters in the existing design.

Finite element analysis of single cylinder four stroke

petrol engines is taken for the study; Structural systems of

Connecting rod can be easily analyzed using Finite Element

techniques. So firstly a proper Finite Element Model is

developed using Cad software Pro/E Wildfire 4.0.Then static

analysis is done to determine the von Misses stress, shear

stress, elastic strain, total deformation in the present design

connecting rod for the given loading conditions using Finite

Element Analysis Software ANSYS v 12.In the first part of

the study, the static loads acting on the connecting rod, After

that the work is carried out for safe design.

Based on the observations of the static FEA and the

load analysis results, the load for the optimization study was

selected. The results were also used to determine of various

stress and the fatigue model to be used for analyzing the

fatigue strength. Outputs of the fatigue analysis of include

fatigue life, damage, factor of safety, stress biaxiality

indication. Then results of present model in ANSYS are

compared with the results of existing design in the reference

paper.

Keywords—ANSYS, Connecting Rod, Finite Element

Analysis, Modeling.

I. INTRODUCTION

The connecting rod connects the piston to the

crankshaft and they form a simple mechanism that

converts linear motion into rotary motion. The maximum

stress occurs in the connecting rod near the piston end due

to thrust of the piston. The tensile and compressive stresses

are produced due to gas pressure, and bending stresses are

produced due to centrifugal effect & eccentricity. So the

connecting rods are designed generally of I-section to

provide maximum rigidity with minimum weight [1]. The

maximum stress produced near the piston end can be

decreased by increasing the material near the piston end.

P G Charkha and Jaju have presented the

Analysis & Optimization of Connecting Rod. Finite

element analysis of single cylinder four stroke petrol

engines is taken as a case study; Structural systems of

Connecting rod can be easily analyzed using Finite

Element techniques. So firstly a proper Finite Element

Model is developed using Cad software Pro/E Wildfire

3.0.Then the Finite element analysis is done to determine

the von Misses stresses in the existing connecting rod for

the given loading conditions using Finite Element Analysis

Software ANSYS WORKBENCH 9.0.In the first part of

the study, the static loads acting on the connecting rod,

After that the work is carried out for safe design. Based on

the observations of the static FEA and the load analysis

results, the load for the optimization study was selected.

The results were also used to determine of various stress

and the fatigue model to be used for analyzing the fatigue

strength. Outputs include fatigue life, damage, factor of

safety, stress biaxiality, fatigue. The component was

optimized for weight subject to fatigue life [1].

M Rasekh et al. have obtained the Maximum

Stresses in Different Parts of Tractor (Mf-285) Connecting

Rods Using Finite Element Method. In this study, detailed

load analysis was performed for a MF-285 Connecting rod,

followed by finite element method. In this regard, in order

to calculate Stress in connecting rod, the total forces

exerted connecting rod were Calculated and then it was

modeled, meshed and loaded in ANSYSv9, software. The

maximum stresses in Different parts of M F-285

connecting rod were determined. The maximum pressure

Stress was between pin end and rod linkages and between

bearing cup and connecting rod Linkage. The maximum

tensile stress was obtained in lower half of pin end and

between Pin end and rod linkages [2].

Vasile George & Imre Kiss presented a method

used to verify the connecting rod’s stress and deformation

using the finite element method with Ansys v.11. The

study only analyses a component of the connecting rod,

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and that is the connecting rod foot, and only for one

challenge (request)-the extension-due to the maximum

inertia [3]

The Connecting Rod considered here for study

belongs to research paper of P.G. Charkha and Jaju

ICETET-09.

II. OBJETIVES

The main aim of the project is to determine the

Von Misses stresses, Shear stresses, and Equivalent

Alternating stress, Total Deformation, Fatigue Analysis

and Optimization in the existing Connecting rod. If the

existing design shows the failure, then suggest the

minimum design changes in the existing Connecting rod.

A lot has been done and still a lot has to be done in this

field. In this Project, only the static FEA of the connecting

rod has been performed by the use of the software. This

work can be extended to study the effect of loads on the

connecting rod under dynamic conditions. Experimental

stress analysis (ESA) can also be used to calculate the

stresses which will provide more reasons to compare the

different values obtained. Now a day a lot is being said

about vibration study of mechanical component important

role in its failure. So the study can be extended to the

vibration analysis of the connecting rod. The study

identified fatigue strength as the most significant design

factor in the optimization process. Then the combination of

finite element technique with the aspects of weight

reduction is to be made to obtain the required design of

connecting rod.

III. STEPS IN MODELING OF

CONNECTING

ROD

Optimized Connecting Rod has been modeled

with the help of PRO/E Wildfire 4.0 software. The

Orthographic and Solid Model of optimized connecting

rod is shown in figures below.

Fig.1: Drawing of Connecting rod (Optimized).

Fig.2: CAD Model of connecting rod in PRO

Engineer.

The following is the list of steps that are use to

create the required model :

a. Choose the reference plane.

b. Set the dimension in mm.

c. Go to sketcher and sketch circular entities.

d. Then extrude these entities for making the both

ends of connecting rod.

e. Again reference plane is selected for shank of

connecting rod.

f. Entities is made that should be tangential to both

ends.

g. Extrude the entities symmetrically.

h. Plane is selected for making entities of groove.

i. Groove is made on the shank and mirrored for

creating groove on both side.

j. Datum plane is selected for creating small holes

on piston end

k. Then holes are made on the periphery of piston

end.

IV. RESULTS OF FINITE ELEMENT

ANALYSIS AND COMPARISION WITH

EXISTING RESULTS

In this study four cases of finite element

models are analyzed. FEA for both tensile and

compressive loads are conducted. Two cases are analyzed

for each case, one with load applied at the crank end and

restrained at the piston pin end, and the other with load

applied at the piston pin end and restrained at the crank

end. In the analysis carried out, the axial load was 4319 N

(Gas Force) in both tension and compression. In addition

to this the analysis carried out taking Buckling Load of

21598N. Finally the comparisons are done for optimization

purpose. The pressure constants for 4319 N are as follows

used for applying

Boundary Condition:

Compressive Loading:

Crank End: Po = 4319/ (17.5 x 10.708 x √3) =

13.31 MPa

Piston pin End: Po = 4319/ (7.8 x 14 x √3) =

22.84 MPa

Tensile Loading:

Crank End: Po = 4319/ [17.5 x 10.708 x (π/2)] =

14.68 MPa

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Piston pin End: Po = 4319/ [7.8 x 14 x (π/2)] =

25.18 MPa

Following are Figures shows the optimized

results along with the results of figures in reference paper

and comparison for static analysis of connecting rod at

load 4319N.

Above figures shows the comparison equivalent

von misses stress at 4319N.

Above figures shows the comparison of shear

stress at 4319N

Above figures shows the comparison of

equivalent elastic strain at 4319N



and comparison for static analysis of connecting rod at

load 21598N.

Above figures shows the comparison equivalent

von misses stress at 4319N.

Above figures shows the comparison of shear

stress at 4319N.

Above figures shows the comparison of

equivalent elastic strain at 4319N

Table: 1. shows the result comparison for static

analysis

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and comparison for fatigue analysis of connecting rod at

load 4319N.

Above figure shows the comparison of safety factor at

4319N.

Above figure shows the comparison of biaxiality

indication at 4319N.



and comparison for fatigue analysis of connecting rod at

load 21598N.

Above figure shows the comparison of safety

factor at 21598N.

Above figure shows the comparison of safety

factor at 21598N.


results a for fatigue analysis of connecting rod at load

4319N along with at load 21598N

Above figures shows the life at 4319N and

21598N

Above figures shows the damage at 4319N and

21598N.

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Table: 2. shows the result comparison for fatigue

analysis

Table 3: -Shows the comparison of Weight

Above table shows the weight optimization of

connecting rod, in existing model weight of connecting rod

was 131.5g. After optimization weight of connecting rod

is126.73, the percentage weight reduction is 3.62.

V. CONCLUSION

Finite Element analysis of the connecting rod of a Hero

Honda Splendor has been done using FEA tool ANSYS

Workbench. From the results obtained from FE analysis,

many discussions have been made. The results obtained

are well in agreement with the similar available existing

results. The model presented here, is well safe and under

permissible limit of stresses.

1. Conclusion is based on the current work that the

design parameter of connecting rod with

modification gives sufficient improvement in the

existing results.

2. The weight of the connecting rod is also reduced

by 0.477g. Thereby, reduces the inertia force.

3. Fatigue strength is the most important driving

factor for the design of connecting rod and it is

found that the fatigue results are in good

agreement with the existing result.

4. The stress is found maximum at the piston end so

the material is increased in the stressed portion to

reduce stress.

REFERENCES

[1] P. G. Charkha, S. B. Jaju (2009) “Analysis &

Optimization of Connecting Rod” Second International

Conference on Emerging Trends in Engineering and

Technology, ICETET-09.

[2] M. Rasekh, M. R. Asadi, A. Jafari, K. Kheiralipour

(2009) “Obtaining Maximum Stresses in Different Parts of

Tractor (Mf-285) Connecting Rods Using Finite Element

Method” Australian Journal of Basic and Applied

Sciences, Vol.3, pp 1438-1449.

[3] V. George, I. Kiss, (2010) “Computer aided design of

the connecting rod”.

[4] ANSYS WORKBENCH 12.0 Reference Manual.

[5] Pro/E Wildfire 4.0 Reference Manual

[6] Sharma. & Aggarwal “Book of machine design”.

design evaluation and optimization of connecting rod

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