The aim of this project to design, simulate and analyze the deformations of a slider crank mechanism’s bodies as a rigid body system and with a flexible connecting rod

1. 1
Design, Simulation and
Deformation Analysis
of a Planar Slider Crank
Mechanism.
NAME:VIJAY ANAND VELMURUGAN
UIN: 678608544

2. 2
 Scope of the Project
The aim of this project to design, simulate and analyze the deformations of a slider crank
mechanism’s bodies as a rigid body system and with a flexible connecting rod. This system
consists of 4 bodies:
1. Ground (body 1)
2. Crankshaft (body 2)
3. Connecting Rod (body3)
4. Slider Block (body 4)
The mechanism consists of 4 mechanical joints:
1. The crankshaft is connected to the ground by a revolute joint at A.
2. The connecting rod is connected to the crankshaft by a revolute joint at B.
3. The slider block is connected to the connecting rod by a revolute joint at C.
4. The slider block is connected to the ground by the prismatic joint at 4.
The following assumptions were made in this project:
1. The body coordinate systems are attached to the body mass centers.
2. Both the crankshaft and connecting rod are assumed to be in the horizontal position at the
initial configuration.
3. The initial velocities are the velocities that correspond to the specified angular velocity of
the crankshaft.
4. The slider block is assumed to have zero mass and the effect of gravity is neglected for all
bodies.

3. 3
The table below shows the dimensions considered for modelling of slider crank mechanism:
 Simulation of Slider Block Mechanism as a rigid body system:
1. Displacement study of Crankshaft:
SL.NO COMPONENT
CROSS
SECTIONAL
DIAMETER
(m)
LENGTH
(m)
MASS
DENSITY
(Kg/m3)
MODULUS
OF
ELASTICITY
(N/m2)
SIMPLE
VELOCITY
CONSTRAINT
(rad/s)
1 Ground 0 0 - - -
2 Crank Shaft 6.35 x 10-3 0.1524 7.89 x 103 2.0684 x 1011 -
3 Connecting Rod 6.35 x 10-3 0.3048 7.89 x 103 2.0684 x 1011 124
4 Slider Block 0 0 - - -

4. 4
2. Displacement study of connecting rod:

5. 5
 Developing FE mesh for the connecting rod using two-dimensional beam element
and floating frame of reference. The FE mesh consists of 4 elements.
 Body reference and co-ordinates of FE mesh of connecting rod. The center of
mass of connecting rod is selected as body reference.
 Distribution of masses across 5 nodes.
 Element Connectivity table.
 Element properties.

6. 6
 Formulas used to calculate element properties.
Property Formula
Mass
ῤπ/4xd2 l
Area π/4xd2
Second moment of Inertia π/4xr4

7. 7
Table below shows modal frequencies and shapes
SL.NO FREQUENCY MODAL SHAPE DESCRIPTION
1. 137.27 Hz Bending
2. 551.11 Hz Bending
3. 1257.69 Hz Bending
4. 2437.13 Hz Bending
5. 3873.81 Hz Bending
6. 4240.94 Hz Axial

8. 8
 Developing flexible multibody systemmodel as a slider crank mechanism.
 Ground Constraint.
 Revolute joint constraints
 Prismatic joint constraints
 Simple velocity constraint on crankshaft

9. 9
 Transverse deformation of midpoint of connecting rod with 3 modes
 Transverse deformation of midpoint of connecting rod with 6 modes.
 Observations:
An important observation is that the transverse deformation of midpoint of
connecting rod is independent of the number of modes selected.

10. 10
 Comparison of displacement of slider blocks-
Flexible body analysis Rigid body analysis

11. 11
APPENDIX