Design and Finite Element Analysis of Knuckle Joint

Using CATIA and ANSYS Workbench

Anupam Raj Jha1, Rakesh Jaiswal2, Anush Karki3, Ankit Basnet4, Pawan
Jaiswal5, Saurav Rajgadia 6, Debayan Das7, Rabindra Nath Barman8
1,2,3,4,5,6,7
B.Tech. Students, 8Assistant Professor, Mechanical Engineering,
National Institute of Technology Durgapur, Durgapur, West Bengal, India

International Journal of Research in Mechanical Engineering

Volume 4, Issue 3, May - June, 2016, pp. 01-05
ISSN Online: 2347-5188 Print: 2347-8772, DOA: 07052016
© IASTER 2016, www.iaster.com

ABSTRACT

Knuckle joint is used to connect two rods whose axes either coincide or intersect and lie in one plane.
It is used to transmit axial tensile force and permits limited angular movement between rods, about
the axis of the pin. As the rods are subjects to tensile force, yield strength is the criterion for the
selection of material for the rods. The pin is subjected to shear stress and bending stress. Therefore,
strength is criterion for material selection for the pin. The objective of this paper is to design and
analyse the structural deformations in a Knuckle joint. Here the Knuckle joint is designed by using
CATIA V5 and analysis is done by ANSYS workbench 14.5.

Keywords: ANSYS, CATIA V5, EN8D, FEA (Finite Element Analysis), Knuckle Joint.

1. INTRODUCTION

A Knuckle joint connects two rods under tensile loads. The basic design of a knuckle joint is simple
and it can be easily assembled and disassembled when required. Typical applications of knuckle joints
are: joints between the links of a suspension bridge, valve mechanism of a reciprocating engine,
fulcrum for the levers, etc. It is unsuitable to connect two rotating shafts which transmit torque. [1][2]
Knuckle joint has mainly three components: Eye, fork and pin as shown in the Fig 1. Eye is formed on
one of the rods and fork is formed on the other. Eye fits inside the fork and the pin is passed through
both the fork and the eye. This pin is secured in its place by means of split-pin. Screwed connections
often play an important part in the transmission of load through machine assemblies. In large circuit
breakers they are subjected intermittently to high impulsive loads transmitted through large-scale
linkages. The material used for the joint is usually steel or wrought iron. [3][4][5].

Fig 1: Eye, Fork and Pin of a Knuckle Joint

International Journal of Research in Mechanical Engineering (O) 2347-5188
ISSN
Volume-4, Issue-3, May-June, 2016, www.iaster.com (P) 2347-8772

The paper presents a FE analysis of the knuckle joint

assembly. The required solid model based on the real life
application and dimension is modelled in CATIA V5.
The model is then discretized and meshed. Analysis is
done in ANSYS workbench after suitable constraints
and load conditions are applied to it. [6]

Fig 2: 3-D Model of a Knuckle Joint

1.1 Material and its Properties

EN8D is a medium carbon and medium tensile steel

used mainly for axles, spindles, studs, automotive and general engineering components. It is suitable
for heat treatment where extra strength is required. It is medium high carbon steel that can be
strengthened by heat treating after forming. Machinability and weldability are fair. Typical uses
include machine, plow and carriage bolts, cylinder head studs, machine parts etc. It is also used for U
bolts, concrete re-enforcing rods, forgings and non critical springs. [7].

Table 1.1.1 (Material Data: EN8D)

Ultimate Tensile Strength 965 Mpa
Tensile Yield Strength 862 Mpa
Poisson’s Ratio 0.28
Elastic Modulus 200Gpa
Young’s Modulus 3.e+005
Bulk Modulus 2.727e+005 Mpa
Shear Modulus 1.1719e+005

2. OBJECTIVE

The objective of this paper is to design a knuckle joint made of EN8D using CATIA V5 and carry out
the finite element analysis (FEA) on the prepared model using ANSYS 14.5 and determine the values
of stress-strain and deformation.

3. DESIGN OF KNUCKLE JOINT

I. Calculation of Permissible Stress
σt N/mm2

σc N/mm2

N/mm2

Fig 3: Typical Cross-Section of a Knuckle Join

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International Journal of Research in Mechanical Engineering (O) 2347-5188
ISSN
Volume-4, Issue-3, May-June, 2016, www.iaster.com (P) 2347-8772

3.1 Notations

D = diameter of each rod (mm)

D1 = enlarged diameter of each rod (mm)
d = diameter of knuckle pin (mm)
d0 = outside diameter of eye or fork (mm)
a = thickness of each eye of fork (mm)
b = thickness of eye end of rod
d1 = diameter of pin head (mm)
II. Calculation of Dimensions
Step 1: Diameter of rod

Step 2: Enlarged diameter of rods (D1)

D1
Step 3: Dimensions of a and b.

Step 4: Diameter of Pin.

Also,

Hence, d = 32 mm
Step 5: Dimensions of d0 and d1
d0
d1
Step 6: Check for stress in eye
σt N/mm2

Hence, σt < 165.4 N/mm2

σc N/mm2
σc < 165.4 N/mm2
N/mm2
< 82.7 N/mm2
Step 7: Check for stress in fork
σt N/mm2
σt < 165.4 N/mm2
σc N/mm2
N/mm2
< 82.7 N/mm2
It is observed that stresses are within limits.

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International Journal of Research in Mechanical Engineering (O) 2347-5188
ISSN
Volume-4, Issue-3, May-June, 2016, www.iaster.com (P) 2347-8772

4. MESHING

CATIA and ANSYS workbench software are used for the Finite Element Analysis of the Knuckle joint.
At first the Knuckle Joint is designed in CATIA software and then the file is saved as IGES format and
imported in the ANSYS workbench software. The next step was to mesh the model as shown in the fig
4, the 10 node tetrahedral element are used as shown in the fig 5.The finite element was generated using
the tetrahedral element of size 1mm.We have divided the part into 2447 element with 4782 nodes. The
reason for choosing this huge number of element was to make our part very complex which enables us
to gain more authentic results based on the high technique of fatigue life calculation.

Fig 4: Mesh Model of Knuckle Joint Fig 5: Meshing Type: Tetrahedral

4.1 Finite Element Method (FEM)

The Finite element method (FEM) is a numerical technique for finding the approximate solutions to
boundary value problems for partial differential equations. It uses subdivision of a whole problem domain
into simpler part, called finite elements and solve the problem by minimizing an associated error function.

4.2 FEA Procedure in ANSYS

Any analysis which is performed by using the Finite element analysis can be divided into the
following steps:
I. Discretization
II. Selection of the displacement model.
III. Deriving element stiffness matrices.
IV. Assembly of overall equations/ matrices.
V. Solution for unknown displacement
VI. Computations for the strains/stresses.

5. ANALYSIS OF KNUCKLE JOINT

Fig 6: Total Deformation Fig 7: Equivalent Elastic Strain

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International Journal of Research in Mechanical Engineering (O) 2347-5188
ISSN
Volume-4, Issue-3, May-June, 2016, www.iaster.com (P) 2347-8772

Fig 8: Equivalent Stress Fig 9: Maximum Shear Stress Fig 10: Maximum Principal Stress

5.1 Results
Table 5.1.1
Parameters Max. Min.
Total Deformation (mm) 0.036056 0
Equivalent Elastic Strain (mm) 0.00053155 1.3167e-15
Equivalent Stress (MPa) 158.79 8.7362e-11
Shear Stress (MPa) 81.744 5.0227e-11
Principal Stress (MPa) 173.32 -9.0991

6. CONCLUSION
This paper, not only deals with the design of a Knuckle Joint but also the stress strain effect applied to
it. In design, the Knuckle Joint is taken to have maximum weight possible with the ability to
withstand high stress and strain. It is found that the stress-strain formed in the EN8D material was
much lower than that compared to Cast Iron or Mild Steel. The maximum stress and strain values are
found to be 158.79 MPa and 0.00053155 mm.

REFERENCES

[1] Design of Machine Elements by VB Bhandari, ISBN: 978-0-07-068179-8, pp 94-100

[2] Nishant Vaibhav Saxenaand Dr. Rohit Rajvaidya, “Study and Analysis of Knuckle Joint with
Replacement of Material by using Teflon”, ISSN: 2248-9622, Vol 5, Issue 3, (part-4) March
2015, pp 67-72.
[3] K.L. Narayan, P Kannaiah, V Venkata Reddy, Machine Drawing, Published by New Age
International (P) Ltd., ISBN (13): 978-81-224-2518-5, pp 113
[4] Shaik. John Bhasha and Hari Sankar Vanka, “Modelling and Analysis of Knuckle Joint”,
(IJMETMR) ISSN: 2348-4845, Volume No: 2 (2015), Issue No: 11 (November).
[5] Kawaljit Singh Randhawa, “Advantage of Knuckle Joint in Pneumatic Press”, Intl. J. of
Research in Mechanical Engineering, Vol.3, Issue 4, pp.43-50.
[6] Gupta, R.S. Khurmi, J.K, A Textbook of Machine Design, Ram Nagar, New Delhi: Eurasia
Publishing House. ISBN 81-219-25371 (2008).
[7] Dinesh Shinde and Kanak Kalita,“FE Analysis of Knuckle Joint Pin Used in Tractor Trailer”,
(ARPN Journal) ISSN 1819-6608, Vol. 10, No. 5, March 2015.
[8] http://saajsteel com/?page_id=1780