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STATIC ANALYSIS OF CONNECTING ROD IN A SINGLE
CYLINDER DIESEL ENGINE
1S.KALIAPPAN
2G R Vignesh
3 N R Vigneshwaran
4R Giritharan
5 Dr.T.Mothilal
6 M.D.Rajkamal
1 Associate Professor, Department of Mechanical Engineering, Velammal Institute of Technology , Chennai, India.
234 UG Student,Department of Mechanical Engineering , Velammal Institute of Technology , Chennai, India.
5 Professor, Department of Mechanical Engineering, Velammal Institute of Technology , Chennai, India.
6 Assistant Professor, Department of Mechanical Engineering, Velammal Institute of Technology , Chennai, India.
ABSTRACT Connecting Rods are generally used in automobile
engines, acting as an intermediate link between the piston and the
crankshaft of an engine, which helps in converting the reciprocating
motion of the piston to the rotary motion to the crankshaft. Generally
connecting rods are made using carbon steel and aluminum alloys. In
our project, we are comparing the factors such as von mises stress,
maximum shear stress, maximum principal stress and total
deformation of aluminium alloys, titanium and a copper alloy. FEA
analysis is carried out by considering three materials. The parameters
like various three stresses, and deformation are obtained from
ANSYS software.
KEY WORDS: Von mises stress, Maximum shear stress,
Maximum principal stress, Total deformation.
I. INTRODUCTION
Every Internal Combustion (I.C.) engine consists of mainly
cylinder, piston, connecting rod, crank and crank shaft. The
Connecting Rod is one of the important parts of an engine. A
single-cylinder engine is a basic piston engine configuration of
an internal combustion engine. It is often seen on motorcycles,
motor scooters, dirt bikes, go-karts, and has many uses in
portable tools and garden machinery. Characteristics of
Single-cylinder engines are simple and compact, and will
often deliver the maximum power possible within a given
envelope. In the basic arrangement they are prone to vibration
though in some cases it may be possible to control this with
balance shafts. A connecting rod is a shaft which connects a
piston to a crank or crankshaft in a reciprocating engine.
Together with the crank, it forms a simple mechanism that
converts reciprocating motion into rotating motion. A
connecting rod may also convert rotating motion into
reciprocating motion. Earlier mechanisms, such as the chain,
could only impart pulling motion. Being rigid, a connecting
rod may transmit either push or pull, allowing the rod to rotate
the crank through both halves of a revolution. Vibration is a
mechanical phenomenon whereby oscillations occur about an
equilibrium point. The oscillations may be periodic, such as
the motion of a pendulum or random. There are generally two
categories for the vibrations the free vibrations and forced
vibrations, free vibrations occur when the system is under the
action of oscillating systems and their inherent forces external
forces there are uncertain. All systems that have mass and
elasticity can be free vibrations, the vibrations that occur in
the absence of external stimulus. Vibrations that occur under
uncertain foreign forces are called forced vibrations, when the
uncertain operating system is oscillating with frequency,
oscillation can be uncertain if the impulse frequency of the
system natural frequency is resonance mode occurs and may
be dangerous, there are large fluctuations. Natural frequency is
the frequency at which a system tends to oscillate in the
absence of any driving or damping force. Free vibrations of an
elastic body are called natural vibrations and occur at a
frequency called the natural frequency. Natural vibrations are
different from forced vibrations which happen at frequency of
applied force (forced frequency). If forced frequency is equal
to the natural frequency, the amplitude of vibration increases
manifolds. This phenomenon is known as resonance. Numbers
of methods are available for the design optimization of
structural system and these methods are based on
mathematical programming technique and optimally designed
using ANSYS software.
II. LITERATURE REVIEW
(1) yeshwant Rao and praveen kumar B.S was find an various
tests, In vibration test, 2748Hz above will be subjected to
failure. In tensile test, the load of 6118.30kgs is breaks and it is
maximum tensile strength of connecting rod. In compression
test, 3615.91kgs is break and it is maximum point of
connecting rod. (2) Swapnil And Patil was analysis the
Connecting rod undergoes noise and vibration frequently. The
maximum von-misses stress generated is 37.618Mpa and the
maximum deformation generated is 0.0047524 mm. (3) G.
Sailaja, S. Irfan Sadaq, Shaik Vaseem Yunus was changed the
material to analysis the static and modal is carried out to
International Journal of Pure and Applied MathematicsVolume 119 No. 12 2018, 14037-14043ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu
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determine the dynamic behavior of connecting rod by
considering deformation, strain and stresses when made with
Beryllium alloy using Analysis software. (4) Dr. N. A.
Wankhade, Suchita Ingale was to evaluate the approximate
values of bending stress acting on different material such as Al
7075, Al6061 and High strength carbon fiber which are used to
compare with the conventional material employed which is
steel. The connecting rod of high strength carbon fiber suffers
lesser in context of bending due to inertia and thus can be best
suited for connecting rod of diesel engine. (5) Satish Wable1,
Dattatray S.Galhe2. The Aluminum MMC connecting rod
shows less amount of stresses (ie.41%) than existing carbon
steel (16MnCr5) connecting rod. It is also found that the
Aluminum MMC connecting rod is light in weight (ie.23%)
than existing carbon steel (16MnCr5) connecting rod
approximately.
III. PROBLEM IDENTIFICATION
In modern automotive internal combustion engines, the
connecting rods are most usually made of steel for production
engines, but can be made of T6-2024 and T651-7075
aluminum alloys (for lightness and the ability to absorb high
impact at the expense of durability) or titanium (for a
combination of lightness with strength, at higher cost) for
high-performance engines, or of cast iron for applications such
as motor scooters. They are not rigidly fixed at right (for
endothermic engine) in steel, the left connecting rod (for
endothermic engine) has the modular head and the foot
equipped with a bushing, the central rod has the oil drip rod
equipped with pats either end, so that the angle between the
connecting rod and the piston can change as the rod moves up
and down and rotates around the crankshaft. Connecting rods,
especially in racing engines, may be called "billet" rods, if
they are machined out of a solid billet of metal, rather than
being cast or forged. Stress and failure of the connecting rod is
under tremendous stress from the reciprocating load
represented by the piston, actually Aluminum connecting rod
for 4-stroke engine, fatigue breakage and subsequent impact
with the crankshaft stretching and being compressed with
every rotation, and the load increases as the square of the
engine speed increase. Failure of a connecting rod, usually
called throwing a rod, is one of the most common causes of
catastrophic engine failure in cars, frequently putting the
broken rod through the side of the crankcase and thereby
rendering the engine irreparable; it can result from fatigue
near a physical defect in the rod.
IV. THEORETICAL DESIGN
Fig 1
V. CALCULATION
Pressure calculation for connecting rod
Engine type 4 stroke air cooled
Bore * stroke = 57 * 58.6 mm
Displacement = 149.5 cc
Maximum power = 13.8bhp@8500rpm
Compression ratio = 9.35:1
Density of petrol (C8H18) = 737.22kg/m3= 737.22E-9 kg/mm
3
Auto ignition temp = 2800 c
Mass = density * volume
= 737.22e9*149.5e
= 0.110214kg
Where, P = Pressure, Mpa
V = Volume
M = Mass, kg
Rspecific = Specific gas constant
T = Temperature, K
Rspecific = R/M
Rspecific = 8.3143/0.114228
Rspecific = 72.76 Nm/kg K
P = m Rspecific. T/V
P = (0.110214*72.757*553)/149.5= 29.67 Mpa
Calculation of analysis is done for maximum pressure of 30
Mpa and 15 Mpa
Design calculation for the connecting rod in general from
standards,
1) Thickness of the flange & web of the section = t
2) Width of the section, B = 4t
3) Height of the section, H = 5t
4) Area of the section, A = 11t^2
5) Moment of inertia about x axis, Ixx = 34.91t
6) Moment of inertia about y-axis, Iyy = 10.91t
International Journal of Pure and Applied Mathematics Special Issue
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7) Therefore Ixx/Iyy = 3.2 (safe because it lies between
3 to 3.5)
8) Length of the connecting rod (L)= 2 times stroke L =
117.2 mm
Total force acting F = Fp – FI
Where
Fp=force acting on the piston
FI=force of inertia
Fp=(2) * gas pressure
Fp = 39473.1543 N
FI = mw2r( )
M = mass of the reciprocating parts
Weight = 1.6 * 9.81 = 15.696 N
r = crank radius π
r = stroke of piston / 2
Also, = crank angle from dead centre
= 0 considering connecting rod is at TDC position
n = length of connecting rod / crank radius
g = acceleration due to gravity, 9.81 m/s2
v = crank velocity m/s
v = r w = 29.3e-3
* 890.1179 = 26.08 m/sec
On substituting these,
FI = 9285.5481
Thus,
F = 39473.1543 – 9285.5481 F = 30187.6062N
Now according to Rankine’s – Gordon formula,
F =
Let,
A = Cross section area of connecting rod,
L = Length of the connecting rod
Fc = compressive yield stress,
F = Buckling load
Ixx & Iyy = Radius of gyration of section about the x
For magnesium alloy:
Fc = 160Mpa
30187.6 =
t = 4.08mm
Width B = 4t = 4*4.08 = 16.32mm
Height H =5t=20.40mm
At the small end (H1) = 0.85*20.40=17.34mm
At the big end (H2) = 1.2H=1.2*20.40=24.48mm
Design of small end :
Load on piston pin (Fp) = projected area * bearing
pressure = dp lp * Pbp
39473.154 = dp * 1.5 dp * 10
dp = 51.29mm
lp = 76.5mm
outer diameter of small end = dp+2tb+2tm
= 51.29 + (2*2) + (2*5)
= 65.29mm
Design of big end :
Fb = dc lc * Pbc = dc *1.25 dc*7.5
39473.154 = 1.25 * 7.5 * dc2
dc = 64.88mm
VI. ANALYSIS
A. Model of the Connecting Rod is Shown Below
Fig-2 model of connecting rod
B. Fine Mesh Model is Shown Below
Fig-3 Fine Mesh Model
C.Analysis of Connecting Rod of aluminium alloy.
1.Equivalent Stress Analysis.
International Journal of Pure and Applied Mathematics Special Issue
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Fig-4 Equivalent Stress Analysis
2.Maximum Shear Stress Analysis
Fig-5 Maximum Shear Stress Analysis
3. Maximum Principal Stress Analysis
Fig-6 Maximum Principal Stress Analysis
4. Total Deformation Analysis
Fig-20 Total Deformation Analysis
D.Analysis of Connecting Rod of titanium alloy
1.Equivalent Stress Analysis
Fig-7 Equivalent Stress Analysis
2.Maximum Shear Stress Analysis
Fig-8 Maximum Shear Stress Analysis
3. Maximum Principal Stress Analysis
International Journal of Pure and Applied Mathematics Special Issue
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Fig-9 Maximum Principal Stress Analysis
4. Total Deformation Analysis
Fig-10 Total Deformation Analysis
E.Analysis of Connecting Rod of copper Alloy
1.Equivalent Stress Analysis
Fig-11 Equivalent Stress Analysis
2.Maximum Shear Stress Analysis
Fig-12 maximum shear stress Analysis
3. Maximum Principal Stress Analysis
Fig-13 Maximum Principal Stress Analysis
4. Total Deformation Analysis
Fig-14 Total Deformation Analysis
International Journal of Pure and Applied Mathematics Special Issue
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VII. RESULT AND DISCUSSION
Table -1: Static structural Analysis of connecting rod with
aluminium inserts using ANSYS.
Parameters Minimum Maximum
Equivalent (Von-
Mises) Stress
(MPa)
0.00033377 14.8
Maximum Shear
Stress(MPa)
0.00018803 7.794
Maximum
Principal
Stress(MPa)
-2.7465 6.6766
Total
Deformation(mm)
0 0.022045
Table -2: Static structural Analysis of connecting rod with
titanium inserts using ANSYS.
Parameters Minimum Maximum
Equivalent (Von-
Mises)
Stress(MPa)
0.00038835 14.683
Maximum Shear
Stress(MPa)
0.00022287 7.7445
Maximum
Principal
Stress(MPa)
-2.9564 6.7424
Total
Deformation(mm)
0 0.016288
Table -3: Static structural Analysis of connecting rod with
copper inserts using ANSYS.
Parameters Minimum Maximum
Equivalent (Von-
Mises)
Stress(MPa)
0.00035527 14.761
Maximum Shear
Stress(MPa)
0.0001994 7.7776
Maximum
Principal
Stress(MPa)
-2.8169 6.6979
Total
Deformation(mm)
0 0.014224
VIII. CONCLUSION
From the above analysis we can conclude that
stresses of all the materials are almost comparable
and also in safe limit
The stresses induced in the small end of the
connecting rod are greater than the stresses induced
at the big end
Solid modelling of connecting rod was made in
fusion 360 according to production drawing
specification and analysis under theeffect of tensile
and compressive loads in terms of pressure is done in
ANSYS Workbench
Comparison is also made between the three materials
tensile stresses and al5083 alloy found least stresses.
IX. REFERENCES
1. yeshwant Rao and praveen kumar B.S “vibration
analysis of two wheeler connecting rod” Volume 3
Issue 6, June 2014.
2. P.Swapnil. J. Patil, Nihal Mulla, Swapnil Yadav,
Niraj Sawant, Sagar Pote” Design and Analysis of
Connecting Rod using Finite Element Analysis” Vol.
4, Special Issue 1, January 2017.
3. G. Sailaja, S. Irfan Sadaq, Shaik Vaseem Yunus,
“Dynamic Analysis of a Connecting Rod Using
FEA,” in Magnetism, ISSN (Print) : 2321-5747,
Volume-5, Issue-5, 2017.
4. Dr. N. A. Wankhade, Suchita Ingale, “Review on
Design and Analysis of Connecting Rod Using
Different Material”, Volume 7 Issue No.5, may 2017.
5. Satish Wable, Dattatray S.Galhe, “ANALYSIS OF
STRESSES INDUCED IN CONNECTING ROD OF
TWO WHEELER ENGINE,” Vol-2 Issue-3 2016
IJARIIE-ISSN (O)-2395-4396.
6. R A Savanoor, Abhishek Patil, Rakesh Patil and
Amit Rodagi, “FINITE ELEMENT ANALYSIS OF
IC ENGINE CONNECTING ROD BY ANSYS,”
ISSN 2278 – 0149, Vol. 3, No. 3, July 2014.
7. AbhinavGautam, K Priya Ajit, “Static Stress
Analysis of Connecting Rod Using Finite Element
Approach”, e-ISSN: 2278-1684,p-ISSN: 2320-334X,
Volume 10, Issue 1 (Nov. - Dec. 2013), PP 47-51.
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