FEM analysis of connecting rod of IC engine

1. Finite Element Analysis of
Connecting Rod of IC Engine
Sachin Shishodia
2020PCD6210

2. ABSTRACT
INTRODUCTION
DEVELOPMENT OF 3D CAD MODEL
INITIAL TESTING : Load analysis
ANALYSIS IN ANSYS : STRESS DISTRIBUTION &
DEFORMATION
STEPS TO FOLLOW
OPTIMIZATION AIM
WHAT TO OPTIMIZE
RESULTS & CONCLUSION

3.  Development of simple 3D CAD model taking the
detailed dimensions.
 The finite element analysis were performed using Ansys.
 Based on the gas pressure variation in the cylinder of an
IC engine, the piston forces were calculated for critical
positions.
 By comparing the induced stress result with the yield
strength of the material, the component was redesigned.
 The induced maximum stress is almost half of the yield
strength of the material. Hence there is an opportunity
to optimize the size of connecting rod to save some mass
ultimately to increase the vehicle fuel efficiency.
 The optimized connecting rod is 11.3% lighter than the
original design.
Abstract

4. • Connecting rod is the
intermediate member
connecting the piston and the
crankshaft of the IC engine.
The piston is the input
reciprocating element and the
crankshaft is the output
rotating element. Therefore
the connecting rod is playing
the vital role in transmitting
the thrust of piston to torque
of crankshaft.
Introduction

5. • The cross-section of the shank may be
rectangular, circular, I-section or H-section.
Generally circular section is used for low speed
engines while I-section is preferred for high
speed engines.
• The Finite Element Analyses (FEA) were carried
out for different load cases and finally saved
some material by iterative intuitive
optimization.
• The calculation of piston forces for different
crank angles and corresponding axial and
normal forces on the connecting rod.

6. INITIAL TESTING : Load Analysis

7. CRANK
ANGLE
PISTON
FORCE
AXIAL AND
NORMAL
FORCE
TENSILE
STRESS
COMPRESSIVE
STRESS
CY. GAS
PRESSURE
DISPLACEMENT
0 degree 8KN 8KN &
0KN
17.55MPa 38.82MPa 18 bar 0.0095 mm
30 degree 16.56KN 16.2KN &
3.17KN
134.3MPa 227.3 MPa 37.3bar 0.304 mm
90 degree 3.5KN 3.26KN &
1.36KN
68.75 MPa 86.47 MPa 8bar 0.136 mm
CONFIGURATIONS OF ENGINE
CONNECTING ROD
PARTICULARS DIMENSIONS
Crank Length 48.5mm
Length of connecting rod 120mm
Piston diameter 75mm
Mass of connecting rod 0.592kg
Maximum gas pressure 37.29bar

8. The cast steel (AISI 1045) was
considered as the connecting rod
material
MATERIAL YIELD STRENGTH ULTIMATE STRENGTH
AISI 449.32MPa 648.03MPa

9. • At the crank angle of 30 where the cylinder
pressure is maximum of 37.3 bar, is the critical
one. In this case the induced maximum stress
is almost half of the yield strength of the
material. Hence there is an opportunity to
optimize the size of connecting rod to save
some mass ultimately to increase the vehicle
fuel efficiency.
OPTIMIZATION AIM

10. The fillet region near big end of the
connecting rod is experiencing
maximum stress.
The thicknesses of both web and flanges
have been reduced by 4 mm in two
iterations.
The mass of the connecting rod is
reduced from 0.592 kg to 0.532 kg.
WHAT TO OPTIMIZE

11. DEVELOPMENT OF 3D CAD MODEL
CAD Model is prepared using CREO Parametric or CATIA
The modified CAD model was prepared, meshed into
tetrahedron elements, the loads and boundary conditions were
applied and then FE analysis was carried out for the critical load
case only.

13. Importing .prt file created in CREO in ANSYS
Workbench after converting it in to .stp format

14. MESH GENERATION
Type of Meshing : Triangular
Number of Elements : 13354
Number of nodes: 21960

16. ANALYSIS IN ANSYS : STRESS DISTRIBUTION &
DEFORMATION

18. • By iterative optimization, the mass of the connecting
rod is reduced from 0.592 kg to 0.532 kg. The
induced maximum tensile and compressive stresses
are 152.1 MPa and 274.2 MPa. Which are well below
the yield strength of the material.
• The final optimized connecting rod is 11.3% lighter
than the original design. The maximum stress
induced is 224.2 MPa which is also well below the
yield strength of the material.
Results & Conclusion
MAXIMUM COMPRESSIVE
STRESS INDUCED :
224.2MPa
YIELD STRENGTH OF
MATERIAL :
449.32 MPa

19. • Mr. J.D.Ramani, Prof. S. Shukla, Dr. P. K. Sharma,
FE-Analysis of Connecting Rod of I.C.Engine by
Using Ansys for Material Optimization, Int.
Journal of Engineering Research and Applications
www.ijera.com ISSN : 2248-9622
• Finite Element Analysis of Connecting Rod of IC
Engine By Prasanta Kumar Samal , Murali B ,
Abhilash , Tajmul Pasha , National Institute of
Engineering, Mysore
REFERENCE