1. design and optimization of a composite drive shaft for an automobile

2. Description of the Problem :
The weight reduction of the drive shaft can have a certain role in the general weight reduction of the vehicle and is a highly desirable goal,
if it can be achieved without increase in cost and decrease in quality and reliability.
It is possible to achieve design of composite drive shaft with less weight to increase the first natural frequency of the shaft and to decrease the bending stresses using various stacking sequences.
By doing the same, maximize the torque transmission and torsional buckling capabilities are also maximized.

3. Aim
This work deals with the replacement of a conventional steel drive shaft with
E-Glass/ Epoxy and
High Strength Carbon/Epoxy

4. Optimum Design Using Genetic Algorithm
The purpose of using Genetic Algorithm is to minimize the weight of the shaft, which is subjected to the constraints such as
torque transmission,
torsional buckling capacities and
fundamental lateral natural frequency.
The design parameters to be optimized are,
Ply thickness
Number of plies required
Stacking sequence of Laminate

5. Composite material
Composites consist of two or more materials or material phases that are combined to produce a material that has superior properties to those of its individual constituents.
The constituents are combined at a macroscopic level and or not soluble in each other.
The individual constituents retain those properties
Advanced composite materials are widely used
- High specific strength
- High specific modulus

6. Purpose and functions of drive shaft
Transfer torque
– engine to rear wheels
– push vehicle forward and reverse
Smooth , uninterrupted flow of power to axles
Transmit torque to the differential gear box
During operation-transmit max low gear torque
Rotate at very fast speeds required
Operate through constantly changing angles b/w transmission, the differential, the axels
Length of the drive must also be capable of changing while transmitting torque

7. DEMERITS IF A CONVENTIONAL DRIVE SHAFT
Less- specific modulus
strength
damping capacity
corrosion resistance
Increased weight
Manufactured in two pieces (increase bending natural frequency )

8. Merits of composite drive shafts
High – specific modulus
strength
corrosion resistance
damping capacity
Decreased weight (one piece)
Reduction in fuel consumption
Greater torque capacity
Lower fatigue life

9. Design of a steel drive shaft

10. Design specifications and requirements
SNO
NAME
UNIT
VALUE 1
Ultimate torque
N-m
3500 2
Max. Speed of Shaft
rpm
6500 3
Length of Shaft mm
1250

11. Mechanical properties of Steel (SM45C)
MEHCHANICAL PROPERTIES
UNITS
STEEL
Young’s Modulus
GPa
207.0
Shear Modulus
Gpa
80.0
Poisson’s Ratio
---
0.3
Density
Kg/
7600
Yield Strength
MPa
370
Shear Strength

12. Torque Transmission capacity of the Drive Shaft

13. Torsional Buckling Capacity of the Drive Shaft
If the value > 5.5 Long shaft
Else it is short shaft
CRITICAL STRESS :
For long shaft
For short and medium shafts

14. The relation between torsional buckling capacity and critical stress is given by

15. Lateral or Bending Vibration using Timoshenko Beam Theory

16. Design of a composite drive shaft

17. Selection of Material properties of e-glass/epoxy and hs carbon/epoxy
SNO
UNIT
E-GLASS/EPOXY
HS CARBON/EPOXY 1
Gpa
50.0
134.0 2
12.0
7.0 3
5.6
5.8 4 -
0.3 5
MPa
800.0
880.0 6
40.0
60.0 7
72.0
97.0 8
Kg/
2000.0
1600.0

18. Torque Transmission Capacity of the Shaft
Lateral or Bending Vibration
Timoshenko Beam Theory

19. DESIGN OPTIMIZATION
Objective Function: The objective for the optimum design of the composite drive shaft is the minimization of weight
Design Variables
Number of plies
Thickness of the ply
Stacking Sequence
The limiting values

20. Design Constraints Torque transmission capacity of the shaft
Bucking torque capacity of the shaft
Lateral fundamental natural frequency
The constraint equations if
= otherwise
= otherwise
= otherwise
C =

21. The constrained optimization can be converted to unconstrained optimization by modifying the objective function as

22. RESULTS AND CONCLUSIONS the ga results are shown
PARAMETERS
STEEL
E-GLASS/EPOXY
HS CARBON/EPOXY 90 L
1250
3.318
0.2431
0.1661
Optimum no. of layers 1 30 22
t(mm)
7.293
2.5542
Optimum stacking sequence -
[46/-64/-15/-13/39/-84/-28/20/ ]
[83/-18/-89/78/-20/-62/-78/71/ ]
Weight(kg)
8.604
4.05
1.12
Weight saving (%)
41.077
85.9

23. GA RESULTS OF E-GLASS/EPOXY DRIVE SHAFT

26. GA RESULTS OF HS CARBON/EPOXY DRIVE SHAFT:

29. CONCLUSIONS
The E-Glass/ Epoxy and HS Carbon/Epoxy composite drive shafts have been designed to replace the steel drive shaft of an automobile
A one-piece composite drive shaft for rear wheel drive automobile has been designed optimally by using Genetic Algorithm with the objective of minimization of weight of the shaft.
The weight savings of the E-Glass/ Epoxy and HS Carbon/Epoxy shafts were equal to % and 85.9% of the weight of steel shaft respectively

30. thank you