Volume 6, Issue 1 MAY 2017

IJRAET

DESIGN AND ANALYSIS OF CONNECTING ROD

1GANTA.KRISHNARJUNA REDDY 2BADDE NAIK VADITHE

1pg Scholar, Department of Mechanical Engineering, nalanda institute of engineering and technology, satenapalli,

Guntur, Andhra Pradesh 522438 2Associate Professor of Mechanical Engineering, nalanda institute of engineering and technology, satenapalli,

Guntur, Andhra Pradesh 522438

ABSTRACT

Connecting rod is one of the most important part in

automotive engine. Connecting rod is the link

between piston and crank shaft. Which it converts

reciprocating motion of piston into rotary motion of

crank shaft. In internal engines connecting rod is

mainly made of steel and aluminum alloys (for light

weight and absorb high impact loads) or titanium (for

higher performance engines and for higher cost).As a

connecting rod is rigid, it may transmit either a push

or a pull and so the rod may rotate the crank through

both halves of a revolution, i.e. Piston pushing and

piston pulling. Earlier mechanisms, such as chains,

could only pull. In a few two-stroke engines, the

connecting rod is only required to push.

In which it undergoes structural deformations. Thus

in this project we are modeling a connecting rod in

solid works 2016 design software and doing static

structural analysis in ansys work bench 14.5

software.

Thus the part which is modeled is converted into igs

file to import in ansys work bench and static

structural analysis is carried out at 16 MPAof

pressure load by applying various materials including

composite materials, materials used in this project are

such as aluminum alloy (which is already existing),

Titanium alloy 42CrMo4 (Special alloy steel),

Aluminum metal matrix (KS1275)

By applying these boundary conditions on connecting

rod the unknown variables such as stress,

deformation, strain, and maximum shear stress are

found using the FEA based software (ANSYS).

1. INTRODUCTION

In a reciprocating position engine to the connecting

rod or conrod connects the piston to the crank or

crankshaft, alongside the crank they form a simple

mechanism converts reciprocating motion into

rotating motion. Connecting rod might also converts

rotating motion into reciprocatory motion.

Traditionally to development of engines they were

first using this manner.

As a connecting rod is rigid, might transmit either

push or pull and then the rod might rotate each halves

of a revolution i.e. Piston pushing and piston pulling.

Earlier mechanisms used like chains, may solely pull

in a very few two-stroke engines, the connecting rod

is barely needed to push. Now days, connecting rods

are best well-known through their use in a internal

combustion piston engines like automotive engines.

These are clearly different forms earlier types of the

connecting rods utilized in stream engines and steam

locomotives.

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Figure1.1 connecting rod with piston

1.1 Importance of Con Rod In Engine

The connecting rod is that the main a part of the

engine, additionally backbone of the engine. There is

most significant of the connecting rod in an engine.

Figure1.2 connecting rod in engine

Connecting rod rotates the crank shaft that helps the

engine to maneuver on or any of the vehicles to rotate

its wheels. It is designed to resist stresses from

combustion and piston movement.

Connecting rods is toward lighter weight

components. It should withstand with greater power

loads though it is lower in weight. The main purpose

of a connection rod is to provide fluid movement

between pistons and a crankshaft and therefore the

connecting rod is beneath tremendous stress from the

load represented by the piston.

When building a high performance engine, great

attention is paid to the connecting rods. The most

effective feature of a connecting rod ought to be the

uniform shape.

The cross section of rod beam design ought to be

spread and minimize stress load over massive

uniformly shaped areas. In operation stress are

generated and radiate from one or more source on a

component because the rod functions.

Top dead center (TDC) is the point at which the

piston is closest to the cylinder head. Bottom dead

center (BDC) is the point at which the piston is

farthest from the cylinder head. Displacement is the

volume that a piston displaces in an engine when it

travels from TDC to BDCduring the same piston

stroke.

2. LITERATURE SURVEY Hippoliti (1993) reported design methodology in use

at piaggio for connecting rod design, which

incorporates an optimization session moreover

neither the details of optimization nor the load under

which optimization was performed were discussed.

Two parametric fe using 2d plane stress and 3d

approach developed by the author were compared

with experimental results and have good agreements

and optimization procedure they developed was

based on the 2d approach.

Pai (1996) explains an approach to optimize shape of

connecting rod subjected to a load cycle and

consisting of the inertia load deducted from gas load

as one extreme and peak inertia load exerted by the

piston assembly mass as the other extreme, with

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fatigue life constraint. Fatigue life defined as the sum

of the crack initiation and crack growth lives, was

obtained using fracture mechanics principles. The

approach used finite element routine to first calculate

the displacements and stresses in the rod; these were

then used in a separate routine to calculate the total

life. The stresses and the life were used in an

optimization routine to evaluate the objective

function and constraints. The new search direction

was determined using finite difference approximation

with design sensitivity analysis. The author was able

to reduce the weight by 28%, when compared with

the original component.

Sonsino and esper (1994) his discussed the fatigue

based on sintered connecting rods design and it’s not

performing optimization of the connecting rod. They

also designed a connecting rod with a load amplitude

fa = 19.2 kn and with different regions being

designed for different load ratios (r), such as, in the

stem fm = -2.2 kn and r = -1.26, at the piston pin end

fm = -5.5 kn and r = -1.82, at the crank end fm = 7.8

kn and r = -0.42. Based on this measurements

performed preliminary fea followed by production of

a prototype.

Ishida et al. (1995) measured the stress variation at

the column center and column bottom of the

connecting rod, as well as the bending stress at the

column center. The plots, shown in figures 1.5 and

1.6 indicate that at the higher engine speeds, the peak

tensile stress does not occur at 360o crank angle or

top dead center. It was also observed 8 that the r ratio

varies with location, and at a given location it also

varies with the engine speed. The maximum bending

stress magnitude over the entire cycle (0o to 720o

crank angle) at 12000 rev/min, at the column

centerwas found to be about 25% of the peak tensile

stress over the same cycle.

While investigating a connecting rod failure that led

to a disastrous failure of an engine, rabb (1996)

performed a detailed fea of the connecting rod. He

explains as well as modeled the threads of the

connecting rod, the threads of connecting rod screws,

the pre-stress in the screws, the diametral interference

between the bearing sleeve and the crank end of the

connecting rod, the diametral clearance between the

crank and the crank bearing, the inertia load acting on

the connecting rod, and the combustion pressure. The

analysis clearly indicated the failure location at the

thread root of the connecting rod, caused by improper

screw thread profile. The connecting rod failed at the

location indicated by the fea. An axi-symmetric

model was initially used to obtain the stress

concentration factors 9 at the thread root. These were

used to obtain nominal mean and alternating stresses

in the screw. A detailed fea including all the factors

mentioned above was performed by also including a

plasticity model and strain hardening. Based on the

comparison of the mean stress and stress amplitude at

the threads obtained from this analysis with the

endurance limits obtained from specimen fatigue

tests, the adequacy of a new design was checked.

Load cycling was also used in inelastic fea to obtain

steady state situation.

In a published sae case study (1997), a replacement

connecting rod with 14% weight savings was

designed by removing material from areas that

showed high factor of safety. Factor of safety with

respect to fatigue strength was obtained by

performing fea with applied loads including bolt

tightening load, piston pin interference load,

compressive gas load and tensile inertia load. The

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study lays down certain guidelines regarding the use

of the fatigue limit of the material and its reduction

by a certain factor to account for the as-forged

surface. They also indicate that buckling and bending

stiffness are important design factors that must be

taken into account during the design process. On the

basis of the stress and strain measurements performed

on the connecting rod, close agreement was found

with loads predicted by inertia theory. The study also

concludes that stresses due to bending loads are

substantial and should always be taken into account

during any design exercise.

3. PROBLEM STATEMENT

3.0 problem statement:

Connecting rod is one of the most critical

components internal combustion. Connecting rod is

connected in between the piston and crank shaft.

While the crank shaft rotates piston moves from

bottom dead centre to top dead centre vice versa. In

this process connecting rod undergoes stress and

deformation. Hence for the connecting rod when the

load is applied, how the stresses and strain are

induced in the component and deformation value, due

to applied load are analysed.

Decreasing these stresses and increasing stability

depends upon the materials applied. Thus in

industrial purpose optimization of connecting rod had

already started. Optimization is really important for

automotive industry especially. Optimization of the

component is to make the less time to produce the

product that is stronger, lighter and less total cost

productions. The design and weight of the connecting

rod influence on car performance. Hence, it effects

on the car manufacture credibility. Change in the

design and material results a significant increment in

weight and also performance of the engine. The

structural factors considered for weight reduction

during the optimization include the buckling load

factor, stresses under the loads, bending stiffness, and

axial stiffness. Thus, the component can give the

higher strength, efficient design and lighter that

would create a major success in the automotive and

manufacturing industry. Among the main objectives

are to improves the engine performance and also to

strengthen the product that is ensure the safety of

human being.

Connecting rod failed due to insufficient strength to

hold the load. Increasing the strength, automatically it

will longer the life cycles of the connecting rod. In

this study, the design of the connecting rod will be

modeled and at the same time increase the strength.

And different materials are applied for gaining more

stability. The study will be focus on the finite

element modeling and analysis. From the analysis

results, the decision whether connecting rod needs to

change in material, load, design etc factors which

induces stress in the component.

3.1 objectives of project

The objectives of the project are as follows

(i) To develop structural modeling of connecting rod

(ii) To perform finite element analysis of connecting

rod

(iii) Suitable material study

(iv) Study of load factors

(v) Study of stress, strain deformation induced in the

connecting rod

(vi) To develop structural optimization model of

connecting rod

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4. DESIGNING OF A CONNECTING ROD BY

USING SOLID WORKS 4.1 Introduction To Solidworks :

Solidworks mechanical design automation software is

a feature-based, parametric solid modeling design

tool which advantage of the easy to learn windows TM

graphical user interface. We can create fully associate

3-D solid models with or without while utilizing

automatic or user defined relations to capture design

intent.

Parameters refer to constraints whose values

determine the shape or geometry of the model or

assembly. Parameters can be either numeric

parameters, such as line lengths or circle diameters,

or geometric parameters, such as tangent, parallel,

concentric, horizontal or vertical, etc. Numeric

parameters can be associated with each other through

the use of relations, which allow them to capture

design intent

A Solid Works model consists of parts, assemblies,

and drawings.

Typically, we begin with a sketch, create a

base feature, and then add more features to

the model. (One can also begin with an

imported surface or solid geometry).

We are free to refine our design by adding,

changing, or reordering features..

4.2 Design procedure of Connecting Rod For designing the Connecting Rod the following procedure has to be follow

2d sketch of a connecting rod

Sketch & extrude

Extrude cut it to 2mm

Make Holes

draw a sketch on front plane for bolting holes

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mirror is used for making for symmetry on both sides

fillet the edges for smooth surfacing

Different Views of Connecting Rods

5. ANALYSIS DEFINATION & STEPS:

The steps needed to perform an analysis depend on

the study type. You complete a study by performing

the following steps:

Create a study defining its analysis type and

options.

If needed, define parameters of your study.

A parameter can be a model dimension,

material property, force value, or any other

input.

Define material properties.

Specify restraints and loads.

The program automatically creates a mixed

mesh when different geometries (solid,

shell, structural members etc.) exist in the

model.

Define component contact and contact sets.

Mesh the model to divide the model into

many small pieces called elements. Fatigue

and optimization studies use the meshes in

referenced studies.

Run the study.

View results.

5.1 Analysis on connecting rod by using ansys 14.5

work bench software

The analysis of connecting rod models are

carried out using ANSYS software using Finite

Element Method. Firstly the model files prepare in

the SOLIDWORKS SOFTWARE. Then are exported to ANSYS software as an IGES

files as shown in figure

Figure5.1 structural analysis

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5.2 Materials and their properties

5.3 Load & fixed support

• Fixed support

• Load Load at 16 MPA

5.3 Meshing Meshing is probably the most important part in any

of the computer simulations, because it can show

drastic changes in results you get. Meshing means

you create a mesh of some grid-points called 'nodes’.

It's done with a variety of tools & options available in

the software. The results are calculated bysolving the

relevant governing equations numerically at each of

the nodes of the mesh. The governing equations are

almost always partial differential equations,

and Finite element method is used to find solutions to

such equations. The pattern and relative positioning

of the nodes also affect the solution, the

computational efficiency & time.

Mesh Type: Tetrahedral

No. of nodes: 16190

No. of elements: 8821

6. STRUCTRUAL ANALYSIS RESULTS

6.1 Material: Aluminium Alloy

Maximum Stress

Total Deformation

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Maximum Strain

6.2 Material: Titanium Alloy Maximum Stress

Total Deformation

Maximum Strain

6.3 Material: 42CrMo4 Maximum Stress

Total Deformation

Maximum Strain

6.4 Material: Al Metal Matrix Maximum Stress

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Total Deformation

Maximum Strain

7. MODAL ANALYSIS RESULTS

7.1 Material: Aluminium Alloy Mode 1

Mode 2

Mode 3

7.2 Material: Titanium Alloy Mode 1

Mode 2

Mode 3

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7.3 Material: 42CrMo4 Mode 1

Mode 2

Mode 3

RESULT TABLE

For comparisons of the results obtained From the

static analysis result tables it is concluded that

42CrMo4 show least stress and least deformation &

strain value on same static load condition.

From the Modal analysis result tables it is concluded

that 42CrMo4 shows Less deformation results for

given frequency. Hence for both Structural and

Modal Analysis 42CrMo4 (Special Alloy Steel) it is

best suitable material for connecting rod.

CONCLUSION

Brief study about connecting rod & it’s

working is done in this project

Modeling and analysis of connecting rod is

done.

Modeling of connecting rod is done in solid

works 2016 design software

The file is saved as igs to import in ansys

workbench

The analysis in ansys is extremely important

prior to the fabrication of connecting rod.

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The static structural, & Dynamic analysis

(modal analysis) has carried out in the ansys

14.5 software package for connecting rod by

different materials like aluminum alloy,

Titanium alloy , 42crmo4 (special steel

alloy) and Aluminum metal matrix

(KS1275)

The material properties and brief

explanation about composites has given.

The utmost stress, strain and deformation

values of static analysis are tabulated on

load condition of 16 MPA.

From result we conclude that on given load

condition of 16MPA Titanium alloy

showing less deformation, while special

alloy steel 42CrMo4 showing less

deformation value.

Hence the materials with low stress values

are also preferable for the fabrication of

connecting rod.

As titanium is very costly material its

application is limited can only use for aero

space industries.

Aluminum metal matrix which is less costly

and less weight ratio showing nearly same

stress value of titanium and less deformation

value after 42CrMo4 can consider best

material for automobile other than general

material.

Model analysis (Dynamic) is performed on

three different modes; deformation values

with respect to different frequencies are

noted and tabulated for each material.

REFERENCES

Abhinavgutam et al. “static stress analysis of

connecting rod using finite element

approach”. Isor journal of mechanical and

civil engineering, volume 10, issue 1(nov –

dec. 2013), pp 47-51.

Ram bansal et al.”Dynamic simulation of a

connecting rod made of aluminium alloy

using finite element analysis approach”. Isor

journal of mechanical and civil engineering,

volume 5, issue 2 (jan – feb. 2013), pp 01-

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Kuldeep b et al. ”analysis and optimization

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AUTHORS

1. Ganta.Krishnarjuna Reddy Department of Mechanical Engineering,

College name:Nalanda institute of engineeringand technology , Village: kantepudi

Mandal: sattenpalli, Dist: guntur A.P, India, Pin:522438 Email id: gkrishnarjunareddy@gmail.com 2.Baddenaik.vadithe

Associate Professor of Mechanical Engineering,

College name:Nalanda institute of

engineeringand technology ,Village: kantepudi

Mandal: sattenpalli, Dist: guntur

A.P, India, Pin:522438

Email id: bharathnaik117@gmail.com