International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Analysis of Connecting Rod Used in Two Wheeler under Static Loading by
FEA
Raviraj Yashwant Taware#1, Abhay Arun Utpat*2
PG Student, Mechanical Engineering Department, SVERI’s COE Pandharpur, Maharashtra, India
Professor, Mechanical Engineering Department, FABTEC Technical Campus Sangola, Maharashtra, India
1
2
Abstract— Connecting rod is a major link inside of a
combustion engine. It connects the piston to the crankshaft and is
responsible for transferring power from the piston to the
crankshaft and sending it to the transmission. There are different
types of materials and production methods used in the creation
of connecting rods. The most common types of materials used for
connecting rods are steel and aluminum. Connecting rods are
widely used in variety of engines such as, in-line engines, Vengine, opposed cylinder engines, radial engines and opposepiston engines. Existing connecting rod is manufactured by using
Cast Iron. This paper describes FEA analysis of connecting rod.
In the present work connecting rod is replaced by materials
ASTM A216 GR WCB and Aluminum 360 for Hero Splendor
motorbike. A 2D drawing is drafted from the calculations. A
parametric model of connecting rod is modelled using CATIA
V5R17 software. Analysis is carried out by using ANSYS
Workbench 15.0 software. The best combination of parameters
like Von mises stress and strain, deformation etc for two wheeler
connecting rod were done in ANSYS Workbench15.0. Finally
these results are compared with each other.
Keywords— Finite Element Analysis, Cast Iron, ASTM A216
GR WCB, Aluminum 360
I. INTRODUCTION
The intermediate component between crank and piston is
known as connecting rod. The objective of C.R. is to transmit
push & pull from the piston pin to the crank pin and then
converts reciprocating motion of the piston into the rotary
motion of crank. The components are big shank, a small end
and a big end. The cross section of shank may be rectangular,
circular, tubular, I- Section, ellipsoidal Section. It sustains
force generated by mass & fuel combustion. The resulting
bending stresses appear due to eccentricities, crank shaft, case
wall deformation & rotational mass. FEA approach deals with
structural analysis along with various parameters which
affects its working & define best solution to overcome the
barriers associated with it. The structural analysis allows
stresses & strains to be calculated in FEA, by using the
structural model. The structural analysis performed to create
high & low stresses region from the input of the material,
loads, boundary condition. FEA approach was adopted in
structural analysis to overcome the barriers associated with the
geometry & boundary condition. It is used to improve
optimize design [3].
Connecting rods that function in internal combustion engines
are subjected to high cyclic loads comprised of dynamic
tensile and compressive loads. They must be capable of
transmitting axial tension and compression loads, as well as
ISSN: 2231-5381
sustain bending stresses caused by the thrust and pull on the
piston and by the centrifugal force of the rotating crankshaft.
Figure 1 presents schematic illustrations of a connecting rod
and its location and function in an engine.
Fig. 1 Schematic Illustrations of a Connecting Rod
II. THEORETICAL CALCULATIONS OF CONNECTING
ROD
A connecting rod is a machine member which is
subjected to alternating direct compressive and tensile forces.
Since the compressive forces are much higher than the tensile
force, therefore the cross-section of the connecting rod is
designed as a strut and the Rankine formula is used.
A connecting rod subjected to an axial load F may buckle
with x-axis as neutral axis in the plane of motion of the
connecting rod, {or} y-axis is a neutral axis. The connecting
rod is considered like both ends hinged for buckling about x
axis and both ends fixed for buckling about y-axis. A
connecting rod should be equally strong in buckling about
either axis [8].
Let,
A = cross sectional area of the connecting rod.
l = length of the connecting rod.
𝜎c = compressive yield stress.
F = crippling or buckling load.
Ixx and Iyy = moment of inertia of the section about x-axis and
y-axis respectively.
Kxx and Kyy = radius of gyration of the section about x-axis
and y- axis respectively.
Rankine’s – Gordon formula,
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F about x-axis =
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
A. Pressure Calculation for 100cc Engine
Hero Splendor Specifications
Engine type air cooled 4-stroke
Bore × Stroke (mm) = 50 × 49.5 = 2475 mm
Displacement = 97.2CC
Maximum Power = 7.5ps (5.5 kW)@8000 rpm
Maximum Torque = 7.95 Nm@8000rpm
Compression Ratio = 9:1
Density of Petrol C8H18 = 737.22kg/m3
= 737.22E-9kg/mm3
Temperature = 60F = 288.855K
Mass = Density × Volume = 737.22E-9×97.2E3
= 0.07165 Kg
Molecular Weight of Petrol 114.228 g/mole
Now,
Length of connecting rod (L) = 2 times the stroke
From Gas Equation,
Maximum Explosion pressure P max = 2.5 MPa
= 8.3143 E3/114228E-3
= 72.786
Compressive yield stress
The maximum gas force,
Where,
R is universal gas constant
is molecular weight of petrol
= 4908.7385 N
Now according to Rankine’s – Gordon formula,
B. Design Calculation of Cast Iron
F about x-axis =
Thickness of flange & web of the section = t
Width of section
The standard dimension of I -SECTION.
F = Pgas x f.s.
F = 4908.7385 x 5
F = 24543.692 N
Rankine Constant,
Now,
Fig.2 Standard dimension of I - Section
F=
Height of section,
Area of section,
MI of section about x axis:
MI of section about y axis:
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Now,
Thickness of flange & web of the section = t= 2.1 mm
Width of section B= 4t = 4 x 2.1 = 8.4 mm
Height of section H=5t = 5 x 2.1 = 10.5 mm
Area of section A= 2(4t×t) +3t×t
A=11t²
A= 48.51 mm2
Height at the big end (crank end) = H2 = 1.1H = 11.55 mm
Height at the small end (piston end) = 0.8 H = 8.4 mm
C. Design Calculation for ASTM A216 GR WCB
Now similarly,
Compressive yield stress
Height of section H=5t = 5 x 2.9 = 14.5 mm
Area of section A= 2(4t×t) +3t×t
A =11t²
A = 92.51 mm2
Height at the big end (crank end) = H2 = 1.1H = 15.95 mm
Height at the small end (piston end) = 0.8 H = 11.6 mm
III. MODELING
The connecting rod of Hero Splendor motorbike is
selected for the investigation. The dimensions of the present
connecting rod are taken with the help of vernier caliper as
tabulated in table 1. According to this dimensions the model
of connecting rod is created by using modelling software
CATIA V5R17. The model of connecting rod is as shown in
figure 3.
TABLE I
DIMENSIONS OF CONNECTING ROD
F=
Sr.
No.
1
2
3
4
5
Parameters
Values
Length of connecting rod
Outer Diameter of Big End
Outer Diameter of Small End
Inner Diameter of Big End
Inner Diameter of Small End
94.1 mm
39.4 mm
19.4 mm
30.0 mm
13.0 mm
Thickness of flange & web of the section = t= 3 mm
Width of section B= 4t = 4 x 3 = 12 mm
Height of section H=5t = 5 x 3 = 15 mm
Area of section, A= 2(4t×t) +3t×t
A =11t²
A = 99 mm2
Height at the big end (crank end) = H2 = 1.1H = 16.5 mm
Height at the small end (piston end) = 0.8 H = 12 mm
Fig. 3 Model of Connecting Rod
D. Design Calculation for Aluminum 360
A. Material Properties
Now similarly,
Compressive yield stress
The different materials used for the connecting rod are cast
iron, aluminium 360 and ASTM A216 GR WCB. The
required mechanical properties for analysis of all the materials
used for connecting rod are shown in the Table 2.
F=
TABLE III
MATERIAL PROPERTIES
Properties of
material
Young’s
Modulus(E)
Cast Iron
ASTM
A216 GR
WCB
Aluminium
360
170 Gpa
210 GPa
71 GPa
Thickness of flange & web of the section = t= 2.9 mm
Width of section B= 4t = 4 x 2.9 = 11.6 mm
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Poisson’s Ratio
Density
Tensile
Strength
0.3
0.3
0.33
7196
kg/m3
7833
kg/m3
2630
kg/m3
200 Mpa
485 MPa
300 MPa
B. Meshing
The next step after modeling is meshing of connecting rod
model. The mesh model of present connecting rod is as shown
in figure 4. Meshing is the initial step in the analysis of finite
element method. Ansys creates the proper mesh of the total
object for further analysis. Thus after meshing of connecting
rod in the Ansys workbench 15.0 load and boundary
conditions are applied.
Fig. 5 Loads & Boundary Condition
IV. RESULTS AND DISCUSSIONS
For the analysis of connecting rod 16 Mpa pressure is
applied as per the numerical results obtained in the design
calculations at small end keeping big end of connecting rod
fixed. The analysis is done using software ANSYS workbench
15.0. The maximum and minimum values of parameters like
von-mises stress, strain and deformation are noted in the
present connecting rod analysis model.
A. Analysis for Material Cast Iron
Fig. 4 Mesh Model of connecting rod
C. Load Diagram of Connecting Rod
A model of connecting rod is created by CATIA V5R17 is
imported for analysis in ANSYS Workbench 15.0. Analysis is
done with the pressure of 16 MPa which is applied at small
end i.e. piston end of connecting rod by fixing the big end.
Part A i.e. big end is fixed and at the part B i.e. small end
force is applied on connecting rod as shown in figure no.5
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Fig. 6 Von- Mises Stress of Cast Iron Connecting Rod
From figure no.6 it is observed that maximum stress
occurs at small end of the connecting rod after applying
pressure of 16 Mpa and minimum amount of stress is
developed at big end of connecting rod which is fixed. The
values of maximum and minimum equivalent stress developed
in the connecting rod are 71347 Pa and 0.04495 Pa
respectively.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
B. Analysis for Material ASTM A 216 Gr WCB
Fig. 7 Elastic Strain of Cast Iron Connecting Rod
Fig. 9 Von- Mises Stress of ASTM A216 Gr WCB Connecting Rod
From figure no.7 the numerical estimated values of
maximum and minimum equivalent strain occurring at small
& big end of connecting rod during static analysis for pressure
of 16 Mpa is 4196 e-7 and 2.6444e-13 respectively. Elastic
strain regions are very correctly distinguished in the figure of
present connecting rod model.
For the other material ASTM A216 Gr WCB same
pressure of 16 Mpa is applied and the stress developed is
approximately as similar to the connecting rod made with
material of cast iron. Figure no. 9 indicates the maximum and
minimum stress developed in connecting rod at small & big
end. The equivalent stress maximum and minimum values are
71.347 MPa and 4.4955e-5 MPa respectively.
Fig. 8 Total Deformation of Cast Iron Connecting Rod
Fig. 10 Elastic Strain of ASTM A216 Gr WCB Connecting Rod
Total deformation of connecting rod after applied
pressure of 16 Mpa is shown in figure no. 8.Small end of
connecting rod will show the maximum deformation & there
will be no any deformation at big end of connecting rod as it
is fixed. The maximum deformation of 1.252 e-8 mm will
occur at small end.
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Elastic strain region at small and big end of connecting
rod is shown in figure no. 10. The maximum and minimum
equivalent strain values are 0.00033975 and 2.1407e-10
respectively. Due to applied pressure there will be change in
original dimensions of the connecting rod and hence strain
developed can be illustrated.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Fig. 11 Total Deformation of ASTM A216 Gr WCB Connecting Rod
Deformation at small end of 0.010135 mm occurs due to
applied pressure to the connecting rod. Analysis shows
maximum deformation taking place at small end and there
will be no any noticeable deformation at fixed end.
C. Analysis for Material Aluminium 360
Fig. 13 Elastic Strain of Al 360 Connecting Rod
Strain regions in connecting rod of aluminium material
are shown in figure no. 13 at big end and small end.
Maximum equivalent strain is 00.0010049 and minimum
strain is6.3317e-10.
Fig. 12 Von- Mises Stress of Al 360 Connecting Rod
For connecting rod of material aluminium 360 FEM
analyses shows the equivalent stress of maximum values of
71.347 MPa and minimum value of 4.4955e-5 MPa. As seen
from figure value of stress is similar to other analysed stress
values of connecting rod of different material.
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Fig. 14 Total Deformation of Al 360 Connecting Rod
Figure no. 14 shows the total deformation of connecting
rod. The maximum deformation of 0.029977 mm takes place
at small end of connecting rod.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
D. Comparison of Results
0.0012
For current study pressure of 16 Mpa is used for analysis
of three different materials of connecting rod. The parameters
like von-misses stress, elastic strain & total deformation is
found out by ANSYS workbench 15.0 is tabulated in table 3.
0.001
STRAIN
0.0008
TABLE IIIII
COMPARISON OF RESULTS
0.0006
0.0004
Sr.
No.
Type
Cast Iron
ASTM
A216 GR
WCB
1
Von- mises
stress
71.347
Mpa
71.347 MPa
Al 360
0.0002
0
CI
71.347
MPa
ASTM A216
Al 360
GR WCB
MATERIAL
3
Elastic strain
Total
deformation
4196 e-7
0.0003397
0.001004
1.252 e-8
mm
0.010135
mm
0.029977
mm
E. Graphs
STRESS (MPa)
Finite element analysis of connecting rod under static
loading condition has been done by ANSYS workbench 15.0
for the pressure of 16 MPa. The results obtained for different
materials of connecting rod are plotted in the following graphs.
Fig. 16 Graph of elastic strain for three materials
0.035
DEFORMATION (mm)
2
0.03
0.025
0.02
0.015
0.01
80
0.005
70
0
CI
60
50
ASTM
A216 GR
WCB
Al 360
MATERIAL
40
Fig. 17 Graph of total deformation for three materials
30
20
10
0
CI
ASTM
A216 GR
WCB
Al 360
MATERIAL
Fig. 15 Graph of Von- mises stress for three materials
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V. CONCLUSIONS
By comparing the results of three different materials used
for connecting rod analysis it is found that equivalent von
mises stress for all the materials is approximately same.
From the static analysis the stress is found maximum at
the small end of the connecting rod.
Comparing the different results obtained from the
analysis of connecting rod it is concluded that the deformation
of ASTM A216 GR WCB is less than the Al 360. So ASTM
A216 GR WCB can be used for production of connecting rod
for long durability.
When compared with cast iron and Al 360, ASTM A216
GR WCB is cheaper than the existing connecting rod material.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
ACKNOWLEDGMENT
This work is just not an individual contribution till its
completion. I take this opportunity to thank all for bringing it
close to the conclusion. I would like to express my heartedly
gratitude, sincere thanks and deep sense of appreciation to Dr.
A. A. Utpat, for continuously assessing my work providing
great and valuable guidance throughout by timely suggestions
and discussions at every stage of this work, making it work in
reality.
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