COVER PAGE
1
Table of Contents
Contents
Table of Contents........................................................................................................................................2
List of Figures...............................................................................................................................................3
List of Tables................................................................................................................................................4
Abstract.......................................................................................................................................................5
INTRODUCTION...........................................................................................................................................6
Methodology...............................................................................................................................................7
3.1 Material Selection..............................................................................................................................7
3.2 Connecting Rod Manufacturing Process............................................................................................7
3.3 Function of a Connecting Rod............................................................................................................8
3.4 FEA Simulation of a Connecting Rod..................................................................................................8
3.4.1 3D CAD Modelling.......................................................................................................................8
3.4.2 Geometry Meshing.....................................................................................................................8
3.4.3 Static Structural Analysis.............................................................................................................9
RESULT AND DISCUSSION..........................................................................................................................10
4.1 FEA Simulation results Visualization................................................................................................10
4.1 FEA Simulation results Graphs.........................................................................................................15
4.2 FEA Simulation Results Discussion...................................................................................................15
4.3 Connecting Rod Design Optimization..............................................................................................15
Conclusion.................................................................................................................................................17
Reference..................................................................................................................................................18
APPENDIX..................................................................................................................................................19
3D CAD Modeling Process.....................................................................................................................19
2
List of Figures
Figure 3. 1: 3D CAD model in SOLIDWORKS........................................................................................10
Figure 3. 2 : Connecting rod mesh in ANSYS model................................................................................10
Figure 4. 1: Directional deformation (X)...................................................................................................12
Figure 4. 2: Equivalent elastic strain..........................................................................................................12
Figure 4. 3: Equivalent stress.....................................................................................................................13
Figure 4. 4: Maximum principal elastic strain...........................................................................................13
Figure 4. 5: Maximum Principal Stress.....................................................................................................14
Figure 4. 6: Maximum Shear Elastic Strain...............................................................................................14
Figure 4. 7: Maximum Shear Stress...........................................................................................................15
Figure 4. 8: Normal Elastic Strain.............................................................................................................15
Figure 4. 9: Normal Stress.........................................................................................................................16
Figure 4. 10: Shear Elastic Strain..............................................................................................................16
Figure 4. 11: Shear Stress..........................................................................................................................17
Figure 4. 12: Total Deformation................................................................................................................17
3
List of Tables
Table 4. 1: Static Structural Simulation Results........................................................................................18
4
Abstract
The field of engineering design (mostly in the automotive engineering world) has placed
essential interest and focus on product or automotive part performance by engaging a well-
structured stress analysis (by simulation) product optimization. This paper work is involves
simulation, analysis and optimization of a connecting rod. The real life loading scenario is
applied in the simulation to study and investigate the behavior of the connecting rod under a
specific subjected loading. Finite element method was engaged to perform the dynamic structural
simulation and analysis using ANSYS workbench as a software package for FEA simulation.
Meanwhile, engineering material selection process was done to investigate and approve a
standard material for the connecting rod as to serve the connecting rod a long service life and
allows a good performance while in operation in an internal combustion engine. Also, the
industrial manufacturing process of the connecting rod is discussed and the automotive
component (the connecting rod) functions in an internal combustion engine are stated.
INTRODUCTION
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An internal combustion engine is generally known to convert or transform chemical energy into
mechanical energy. This could be achieved by reciprocating movement of the engine’s piston.
This IC engine contains a number of mechanical components whereby some are static and others
are dynamic in motion. Some of the mechanical components are crank shaft, piston, cylinder,
gudgeon pin, crank case, ring, valves and connecting rod. The engine connecting rod is included
among the most essential mechanical parts of an internal combustion engine. It primarily
functions in the process of piston reciprocating motion to convert the chemical energy to thermal
energy and to mechanical drivable energy.
At design stage of a connecting rod, sufficient material strength is required to be considered so as
to withstand the loading which could be mechanical loading, thermal loading, and even
vibrational load while the weight of the connecting rod material is still kept at optimal amount.
That is the amount of material used is optimized for cost of production reason. The recent
industrial design of connecting rod for internal combustion engine uses SAE1141 carbon steel as
the production material.
The technology or the science of finite element analysis in the field of engineering can be traced
to a Russian-Canadian scientist known by name as Alexander Pavlovich Hrennikoff. He
presented his finite element analysis discovery in the year 1941. In the year 1942, a German-
American mathematician called Richard Courant also presented his successful work on finite
element analysis. Both Alexander Pavlovich Hrennikoff and Richard Courant demonstrated the
concept of mesh (which means discretization of a component domain) to provide a collection of
sub-domain. Each mesh will then have element and nodes that made it up. Now, in the industry
of product design, finite element analysis (FEA) becomes the solution to analysis stress using
mathematical model approach. Finite element analysis becomes an essential simulation
techniques in automotive, mechanical, structural and aerospace engineering industries. Modern
development of finite element analysis (FEA) now engages the use of electronic computer
system to develop FEA program from mathematical models. The program is written to import
3D CAD model or geometry, select material with its mechanical properties for the geometry,
perform meshing (that is discretization of the geometry domain into sub-domain having elements
and nodes), input boundary conditions, run simulation and visualize the FEA results. In
summary, there are three basic grouped steps which are: pre-processing, processing and post
processing. There are some industrial some developed to accurately perform FEA simulation.
Examples of such software include: ANSYS workbench, SOLIDWORKS simulation, ABAQUS,
NISA, NASTRAN, STAAD-Pro and many more. Among the mentioned finite element analysis
software program, ANSYS will be the point of interest in this paper.
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Methodology
3.1 Material Selection
Connecting rod functions primarily in transmitting mechanical load from piston to the crankshaft in a
reciprocating motion at piston and rotary motion at crankshaft engine. While in motion it’s always under
a high inertia forces, bending forces and axial forces. All these force as a result of high speed. In the
design of a connecting rod, aim is to minimize stress and optimize the material of production. Research
shows that there are three basic materials used in connecting rod production which is aluminum alloy,
steel and titanium. Aluminum material is considered to produce a connecting rod due to its light weight,
higher strength ratio, low cost and high shocking absorbing capacity. Steel also with its properties link:
stability, durability, high tensile strength, grain structure and heat treatment. Also, titanium is expensive
for production of connecting rod, it’s denser, it has high deformation (or elongation) and has fatigue
property. Among all these properties, steel is better for its mechanical properties for an average
connecting rod.
3.2 Connecting Rod Manufacturing Process
A SAE1141 carbon steel connecting rod passes through three major manufacturing processes. The
processes are (1) hot forging (2) heat treatment and (3) machining.
Hot Forging process is the basic first stage of manufacturing or producing connecting rod for an internal
combustion engine. This process of manufacturing is suitable for a steel connecting rod. Hot forging
process consists of some major processing steps which include: producing slug by mean of shaping and
rolling of billet. The billet is always treated first before introduced to the shape rolling process. The billet
treatment happens with a high but suitable temperature. Other forging steps are close die forging of slug,
forging flash cut-off which simply means trimming and punching.
Heat treatment is another manufacturing process of producing steel connecting rod. The heat treatment is
always performed after the processing stage of rough forging. This process is always engaged to alter the
mechanical properties of the steel material of the connecting rod like achieving pearlitic or ferrite pearlitic
structure. Heat treatment process also functions for hardening the SAE1141 carbon steel material of the
connecting rod used in internal combustion engine which is followed by annealing process. High
mechanical properties could be archived by engaging hardening process as such to obtain a martensitic
structure. If the heat treatment process is done while the recently forged SAE1141 carbon steel
connecting rod is still hot, a controlled cooling operation will be used so as to get pearlitic or ferrite
pearlitic structure or to get bainitic structure.
Machining process works on trueing the side faces of the connecting rod and boring of the two ends.
Drilling of holes so as for the connecting rod to receive fixing bolts for the two separated parts at the big
end is also engaged
3.3 Function of a Connecting Rod
As an automotive engine component, a connecting rod functions as a mechanical linkage between the
crankshaft and the piston to transmit power. Another basic function of a connecting rod inside an internal
combustion engine is to deliver lubricating oil to the gudgeon pin and the engine cylinder wall
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3.4 FEA Simulation of a Connecting Rod
3.4.1 3D CAD Modelling
The 3D model of the connecting rod shown in Figure 3.1was modelled using SOLIDWORKS 2D and 3D
modelling environment and saved as a STEP 203 file for ease exporting of the model to ANSYS
Workbench for the transient structural analysis. The primary aims of this analysis is to investigate the
magnitude of dynamic physical loading on the connecting rod, concentration of stress, distribution of
stresses and strain over the model and the effects of these physical and mechanical or material
phenomenon.
Figure 3. 1: 3D CAD model in SOLIDWORKS
3.4.2 Geometry Meshing
Tetrahedral meshing operation was performed in ANSYS workbench. A mesh of 160639 elements and
302094 numbers of nodes was generated. Mechanical APDL solver preference was used with each
element size of 5mm. The discretized (or meshed) model is as shown in figure 3.2.
Figure 3. 2 : Connecting rod mesh in ANSYS model.
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3.4.3 Static Structural Analysis
Static structural analysis was performed to investigate the stress distribution along the connecting rod.
Assumption were made to ease the simulation process since the analysis is not a rigid body simulation
(where the assembly of the connecting rod with its neighboring parts which are piston, crankshaft etc. are
linked). First, the face from the connecting rod that should link with a face from crankshaft was assumed
to be fixed while the force causing pressure was input to the connecting rod face linked to the gudgeon
pin. Two force components were applied. The first force component is in the perpendicular direction to
the gas pressure direction and it’s of magnitude 330N. The second force component was made in parallel
with the direction of the gas pressure direction and it’s of magnitude 1676.9N. Gravitational effect of
−2
9.81 m s was applied in the simulation set-up so as to include the effect of gravity as a force
component.
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RESULT AND DISCUSSION
4.1 FEA Simulation results Visualization
Figure 4. 1: Directional deformation (X)
Figure 4. 2: Equivalent elastic strain
Figure 4. 3: Equivalent stress
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Figure 4. 4: Maximum principal elastic strain
Figure 4. 5: Maximum Principal Stress
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Figure 4. 6: Maximum Shear Elastic Strain
Figure 4. 7: Maximum Shear Stress
12
Figure 4. 8: Normal Elastic Strain
Figure 4. 9: Normal Stress
13
Figure 4. 10: Shear Elastic Strain
Figure 4. 11: Shear Stress
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Figure 4. 12: Total Deformation
4.1 FEA Simulation results Graphs
Figure 4. 13 Directional deformation of the connecting rod.
Figure 4. 14 Shear stress of the connecting rod
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Figure 4. 15 Normal stress of the connecting rod
Figure 4. 16 Maximum shear stress of the connecting rod
Figure 4. 17 Total velocity of the connecting rod
Table 4. 1: Static Structural Simulation Results.
S/No Parameters Unit Minimum Maximum Average
1 Directional deformation (X) m -2.6151e-005 1.1931e-005 -2.383e-006
2 Equivalent elastic strain 6.7079e-011 2.1224e-004 3.789e-005
3 Equivalent stress Pa 2.8375 4.3051e+007 7.636e+006
4 Maximum principal elastic strain -1.3192e-007 1.3356e-004 1.8491e-005
5 Maximum principal stress Pa -3.5541e+006 3.0359e+007 1.9553e+006
6 Maximum shear elastic strain Pa 1.9965e-011 2.8744e-004 5.0437e-005
7 Maximum shear stress Pa 1.5588 2.2442e+007 3.9379e+006
8 Normal elastic strain -7.4969e-005 1.0653e-004 5.791e-006
9 Normal stress Pa -1.6575e+007 2.529e+007 -27798
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10 Shear elastic strain -2.336e-004 1.7533e-004 1.1009e-005
11 Shear stress Pa -1.8239e+007 1.3689e+007 8.5958e+005
12 Total deformation m 0. 9.6422e-005 2.414e-005
4.2 FEA Simulation Results Discussion
Table 4.1 shows the Simulated parameters which are known as the results and displaces there
essential required value. The minimum value, maximum value and average values of the stress,
strain and deformation are all well stated in there SI unit.
4.3 Connecting Rod Design Optimization
From Table 4.1, the minimum, maximum and average simulated values of stress, strain and deformation
are shown and figure 4.1 to figure 4.12 show the visualization. The connecting rod was design and
simulation by assuming a factor of safety of 1. From material database for cast steel the tensile yield
strength is around 0.25GPa, compressive yield strength is approximately 0.25GPa, tensile ultimate
strength 0.25GPa and compressive ultimate strength of 0GPa. ANSYS workbench static structural
analysis tool produced table of maximum shear stress as shown in Table 4.1. The maximum shear stress is
13689000 Pa which is 0.013689 GPa. Since the tensile ultimate strength is 0.25GPa, it can now be said
that SAE1141 carbon steel material used to design the connecting rod with the static loading of
F X =330 N and F y =1696.7 N is safe to use since the maximum shear stress of 0.013689 GPa is less
than 0.25GPa tensile yield strength.
For the purpose of factor of safety, if a Factor of safety of 4 is suggested for the design, then the tensile
ultimate strength of the connecting rod SAE1141 carbon steel material thereby becomes 2.98836MPa. It
is obvious the new maximum shear stresses the structure could undergo is still far lesser than the tensile
yield strength. Therefore, the SAE1141 carbon steel material used for the steel stair would never fail
while in operation.
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CONCLUSION
The essential of stress analysis in the field of automotive engineering in respect to its mechanical parts
(both the static parts and the driving parts) has been established in this work. This establishment was with
an objective to run a stress analysis to investigate stress distribution in a connecting rod member and
perform a product optimization to approve a standard method of designing a better connecting rod. Finite
element analysis (or finite element method) was engaged to run a static structural analysis assuming the
connecting rod is loaded as an instance of motion (that is a static position). ANSYS workbench was used
as computer simulation program software to perform importing connecting rod geometry, selecting
material having required mechanical properties, meshing, boundary condition set-up and post-processing.
Reference
18
[1] 1NIKHIL U.THAKARE, 2NITIN D. BHUSALE, 3RAHUL P.SHINDE, 4MAHESH M.PATIL, "FINITE ELEMENT
ANALYSIS OF CONNECTING ROD USING ANSYS," International Journal of Advances in Science
Engineering and Technology, vol. 3, no. 2, pp. 82-85, April 2015.
[2] Prasanta Kumar Samal, Murali B, Abhilash, Tajmul Pasha, "Finite Element Analysis of Connecting Rod
of IC Engine," 2015.
[3] M. et, Finite Element Analysis of a connecting rod in ANSYS: An overview, IOP, 2020.
[4] R A Savanoo, Abhishek Patil, Rakesh Patil,Amit Rodagi, FINITE ELEMENT ANALYSIS OF IC ENGINE
CONNECTING ROD BY ANSYS, 2014.
[5] AbhinavGautam, K Priya Ajit, "Static Stress Analysis of Connecting Rod Using Finite Element
Approach," vol. 10, no. 1, pp. 48-50, 2013.
APPENDIX
3D CAD Modeling Process
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