Vibration Analysis of Composite Leaf Spring for a Light

International Journal of Scientific Engineering and Technology (ISSN : 2277-1581)

Volume No.3 Issue No.7, pp : 871-875 1 July 2014

IJSET@2014 Page 871

Vibration Analysis of Composite Leaf Spring for a Light Commercial Vehicle

(TATA ACE)

Manjunath H.N1, Manjunath.K

2, T.Rangaswamy

3

1M.Tech Student, Dept. of Mechanical Engineering, Govt. Engineering College, Hassan 2

Asst.Professor, Dept. of Mechanical Engineering, Govt. Engineering College, Hassan 3Professor and Head, Dept. of Mechanical Engineering, Govt. Engineering College, Hassan

[email protected],

[email protected],

[email protected]

Abstract— Vibration analysis plays a very important role in

the design of composite leaf spring, since the failure due to

vibration is more prominent rather than material failure. In

this research work an attempt has been made to predict the

vibration behavior of leaf spring under dynamic forces and to

check the suitability of composite materials like E-

Glass/Epoxy, Graphite/Epoxy, Boron/Aluminum,

Carbon/Epoxy and Kevlar/Epoxy for light commercial vehicle

leaf spring. First the modal analysis is performed to determine

the eigen values (natural frequencies) and mode shapes (eigen

vectors), Harmonic analysis is carried out to determine the

amplitude of response and random vibration analysis is

carried out for smooth and rough road excitations using FE

solver ANSYS V10. Obtained results show that

Boron/Aluminum is best suitable composite material for leaf

spring from vibration point of view.

Keywords—leaf spring, composite, Conventional steel leaf

spring

I. Introduction

Composite materials consist of two or more physically

dissimilar and instinctively separable components called

reinforcement and matrix. These two components can be mixed

in a restricted way to achieve optimum properties, which are

superior to the properties of each individual component.

Composite materials have been widely used in automobile

industry because of its high strength and modulus to weight

ratio, low cost and flexibility in material and structure design.

The suspension leaf spring is one of the potential items for

weight reduction in automobile as it accounts for ten to twenty

percent of the unsprung weight. This helps in achieving the

vehicle with improved riding qualities. Since the strain energy

in the spring is inversely proportional to density and young’s

modulus of the material, it is always suggested that the material

for leaf spring must have low density and modulus of elasticity.

Many research have been carried out in the direction to replace

conventional steel leaf spring by composites. Ramamurti et al.

[13], (1990), have studied bus body vibration and also compared

theoretical and experimental response acceleration and stress

using random vibration concepts. Karuppaiah et al. [12] (2002),

have conducted vibration analysis of a light passenger vehicle

using a half car rigid body model and a finite element model.

The power spectral densities of acceleration of road sections

measured were fed as input load and the dynamic response of

the vehicle was computed in frequency domain using finite

element models and random vibration concept. Manjunath [14]

(2002) has carried out random vibration analysis of a bus body

structure using FEM. Rangaswamy et al. [15] (2005), have

proposed a design methodology for drive shaft of passenger

vehicles by considering torsional transmission capability,

bending natural frequency and buckling torque as design

constraints and number of plys, stacking sequence and thickness

of the play as design variables. Shiva Shankar and Vijayarangan

[5] (2006) have designed, fabricated (hand- lay up technique)

and tested of a single leaf with variable thickness and width for

constant cross sectional area of unidirectional glass fiber

reinforced plastic (GFRP). Senthil Kumar and Vijayarangan [6]

(2007) have carried out design and experimental fatigue

analysis of composite multi leaf spring using data analysis.

Patunkar and Dolas [8] (2011) have carried out modeling and

analysis of composite mono GFRP leaf spring. Shishay [1]

(2012) has designed and simulated a single E-glass/Epoxy leaf

spring for light weight three wheeler vehicles. Ranjeet et al. [2]

(2012) have carried out stress analysis of mono composite leaf

spring under the dynamic load conditions. Anuraag and

VenkataSivaram [7] (2012) have modeled and analyzed two &

five layered composite leaf spring to predict the behavior under

static, dynamic & shock loads. Vijaya Lakshmi and

Satyanarayana [10] (2012) have compared the steel and

composite leaf spring for load carrying capacity, stiffness and

weight savings point of view. Sailaja et al. [3] (2013) have

modeled and analyzed a master leaf spring made up of carbon

fibre, boron fibre and conventional steel with respect to weight

and strength. Digambar et al. [4] (2013) have analyzed steel leaf

springs made of SUP 10 & EN 45. Ghodake and Patil [9] (2013)

have presented the design and analyzed the composite leaf

spring made of glass fibre reinforced polymer. From the

literature survey it is observed that the vibration analysis of

mono composite leaf spring and the performance characteristics

with respect to random vibration has not been done to check the

suitability of leaf spring for automotive suspension application.

II. Leaf Spring Specifications of TATA ACE

In this research work TATA ACE mono composite leaf

spring with constant width and constant thickness with uniform

cross section is considered and is as shown in Figure1. The

design parameters such as spring length, spring thickness,

spring width and camber are kept to be the same in both steel

and composite leaf springs. The specifications of leaf spring are

shown in table 1. The material properties of 55Si2Mn90 steel

are shown in table 2.



IJSET@2014 Page 872

Figure 1 2D drawing of TATA ACE Master Leaf Spring

Table 1 Leaf Spring Specifications of TATA ACE Total Length (L) 930 mm

Length of leaf spring from Eye to Eye 754 mm

Thickness (t) 8 mm

Width (b) 60 mm

Load (W) given on leaf spring 1000 N

Table 2 Material Properties of 55Si2Mn90 Steel [5] 1 Ultimate tensile strength Su (Mpa) 1962

2 Yield tensile strength Su (Mpa) 1470

3 Modulus of elasticity E (Gpa) 210

4 Poisson ratio 0.3

III. Design Requirements of Composite Leaf

Spring

The objective for the optimum design of the composite leaf

spring is the minimization of weight, this objective function is

constrained by the functional requirements of the leaf spring,

which is,

Fundamental natural frequency in bending : maxcrt NN Thus

together with constraints from the functional requirements, the

objective function is optimized by varying the design variables

so that functionally sound, minimum weight leaf spring is

realized. Material

properties of different composites are listed in the table 3.

Table 3 Material Properties of different Composite Materials

[11]

Material

Properties

E-Glass/

Epoxy

Graphite/

Epoxy

Boron/

Aluminum

Carbon

/ Epoxy

Kevlar/

Epoxy

E11 (MPa) 34000 142600 215000 142000 80000

E22 (MPa) 6530 9600 14410 9810 5500

G12 (MPa) 2433 600 5720 657 220

G22 (MPa) 1698 310 4590 377 180

V12 0.217 0.25 0.19 0.3 0.34

V23 0.366 0.35 0.29 0.34 0.65

IV. Finite Element Analysis of Steel and

Composite Leaf Spring

A. Modal Analysis

Modal analysis is a technique used to obtain Eigen

value and Eigen vectors under forced free vibration. The first two

bending frequency modes of Steel, E-Glass/Epoxy,

Graphite/Epoxy, Boron/Aluminum, Carbon/Epoxy and

Kevlar/Epoxy leaf springs are as shown in Figures 2 to 7

respectively.

Figure 2 First and Second Bending Frequency modes of Steel

Leaf Spring

Figure 3 First and Second Bending Frequency modes of E-

Glass/Epoxy Leaf Spring

Figure 4 First and Second Bending Frequency modes of

Graphite/Epoxy Leaf Spring


Boron/Aluminum Leaf Spring


Carbon/Epoxy Leaf Spring



IJSET@2014 Page 873


Kevlar/Epoxy Leaf Spring

B. Harmonic Analysis Harmonic response analysis is a technique used to

determine the steady-state response of a linear structure to

loads that vary harmonically with time. The harmonic

response of Steel, E-Glass/Epoxy, Graphite/Epoxy,

Boron/Aluminum, Carbon/Epoxy and Kevlar/Epoxy leaf

springs are as shown in Figures 8to 10 respectively.

Figure 8 Harmonic responses of Steel and E-Glass/Epoxy Leaf

Springs

Figure 9 Harmonic responses of Graphite/Epoxy and

Boron/Aluminum Leaf Springs

Figure 10 Harmonic responses of Carbon/Epoxy and

Kevlar/Epoxy Leaf Springs

C. Random Vibration Analysis An automobile moving on smooth or rough road is

subjected to random base excitation. The road profiles

measured for some portions of smooth and rough road for

vehicle moving with speed of 30 km/hr is given in Figure

11[12]. Initially the road profiles are measured in time

domain and converted in to frequency domain (power spectral

density) using fast Fourier transformer as shown in Figure

12[12].

Figure 11 Smooth and Rough Road Profiles [12]

Figure 12 Smooth and Rough Road Profiles Acceleration

PSD[12]

The displacement and von mises stress distributions of Steel, E-

Glass/Epoxy, Graphite/Epoxy, Boron/Aluminum,

Carbon/Epoxy and Kevlar/Epoxy leaf springs for both smooth

and rough excitations are as shown in Figures 13 to 24

respectively.

Figure 13 Displacement contour and Von Mises Stress

Distribution of Steel Leaf Spring for Smooth Excitation


Distribution of E-Glass/Epoxy Leaf Spring for Smooth

Excitation


Distribution of Graphite/Epoxy Leaf Spring for Smooth

Excitation



IJSET@2014 Page 874


Distribution of Boron/Aluminum Leaf Spring for Smooth

Excitation


Distribution of Carbon/Epoxy Leaf Spring for Smooth

Excitation


Distribution of Kevlar/Epoxy Leaf Spring for Smooth

Excitation


Distribution of Steel Leaf Spring for Rough Excitation


Distribution of E-Glass/Epoxy Leaf Spring for Rough

Excitation


Distribution of Graphite/Epoxy Leaf Spring for Rough

Excitation


Distribution of Boron/Aluminum Leaf Spring for Rough

Excitation


Distribution of Carbon/Epoxy Leaf Spring for Rough Excitation


Distribution of Kevlar/Epoxy Leaf Spring for Rough Excitation

VI. Result and Discussion

A. Modal Analysis of Steel and Composite Leaf

Springs The results obtained from analysis for steel and various

composite leaf springs are tabulated in table 4 respectively.

From table 4, it is observed that Boron/Aluminum posses high

natural frequency compared to other materials.

Table 4 Natural Frequencies of various Leaf Springs

Material

Natural Frequencies in Hz

Mode 1 Mode 2

Steel 22.912 100.81

E-Glass/Epoxy 14.694 59.612

Graphite/Epoxy 21.067 67.085

Boron/Aluminum 39.836 147.17

Carbon/Epoxy 21.610 69.158

Kevlar/Epoxy 9.4525 29.520

B. Harmonic Analysis of Steel and Composite

Leaf Springs

The response for steel and composite leaf springs at

their corresponding resonance frequencies are tabulated in

table 5. It is observed that E-glass/Epoxy and Kevlar/Epoxy

are having more amplitude of response when compared to all

other materials. The Steel and Boron/Aluminum are having

less amplitude of response compared to other materials.



IJSET@2014 Page 875

Table 5 Harmonic Analysis Results for various Leaf Springs

Material Frequency (Hz) Amplitude

(mm)

Steel 23.509 0.88


Graphite/Epoxy 21.528 5




C. Random Vibration Analysis of Steel and

Composite Leaf Springs

The results obtained for steel and composite leaf

springs for both smooth and rough road excitations are

tabulated in the tables 6 and 7 respectively. FEA solver results

shows that the deflection and von mises stress for

Boron/Aluminum leaf spring is comparatively less than other

leaf springs, hence vibration capacity is more in composite

leaf spring than conventional steel leaf spring.

Table 6 Random Vibration Analysis results of various Leaf

Springs for Smooth Road Excitation

Material Maximum

Deflection

(mm)

Maximum

Von Mises

Stress (MPa)

Steel 2.035 21.891





Kevlar/Epoxy 7 6.131

Table 7 Random Vibration Analysis results of various Leaf

Springs for Rough Road Excitation

Material Maximum

Deflection

(mm)

Maximum

Von Mises

Stress (MPa)

Steel 2.843 31.356






VII. Conclusion

In this research work, eigen value, harmonic and

random vibration analysis for steel and various composite leaf

springs is carried out using ANSYS 10. From the obtained

results it can be concluded that,

1. Boron/Aluminum high natural frequency compared to

other materials.

2. E-Glass/Epoxy and Kevlar/Epoxy are having high

amplitude of response than other materials. And also

3. Steel and Boron/Aluminum have minimum amplitude

of response.

4. Boron/Aluminum has minimum deflection and von

mises stress compared to other materials

Boron/Aluminum possesses more vibration capacity than

conventional steel leaf spring. And also it has good performance

characteristics as compared with other materials with similar

design specifications.

References

i. Shishay Amare Gebremeskel “Design, Simulation, and Prototyping of Single Composite Leaf Spring for Light Weight Vehicle” Global Journal of

Researches in Engineering (A) Vol. 12, Issue 7, Version 1.0, 2012, pp. 21-30.

ii. Ranjeet Mithari, Amar Patil, Prof. E. N. Aitavade “Analysis of Composite Leaf Spring by Using Analytical and FEA” ISSN 0975-5462

International Journal of Engineering Science and Technology Vol. 4 No. 12,

Dec 2012, pp. 4809-4814. iii. N.Anu Radha, C.Sailaja, S.Prasad Kumar, U.Chandra Shekar Reddy

and Dr. A.Siva Kumar “Stress Analysis and Material Optimization of Master

Leaf Spring” ISSN 2319 – 4847 International Journal of Application or Innovation in Engineering and Management Vol. 2, Issue 10, 2013, pp. 324-

329.

iv. Zoman Digambar B, Jadhav Mahesh V, R R Kharde and Y R Kharde “FEA Analysis of Master Leaf Spring” ISSN 2319-2240 International Journal

of Mechanical Engineering (IJME) Vol. 2, Issue 1, Feb 2013, pp. 51-58.

v. Gulur Siddaramanna Shiva Shankar, Sambagam vijayarangan “Mono Composite Leaf Spring for Light Weight Vehicle – Design,End Joint

Analysis and Testing” ISSN 1392–1320 MATERIALS SCIENCE

(MEDŽIAGOTYRA). Vol. 12, No. 3, 2006, pp. 220-225. vi. Mouleeswaaran Senthil Kumar, Sabapathy Vijayarangan

“Analytical and Experimental Studies on Fatigue Life Prediction of Steel and

Composite Multi-leaf Spring for Light Passenger Vehicles Using Life Data Analysis” ISSN 1392–1320 MATERIALS SCIENCE Vol. 13, No. 2, 2007.

vii. K.A. SaiAnuraag, BitraguntaVenkataSivaram “Comparison of Static,

Dynamic & Shock Analysis for Two & Five Layered Composite Leaf Spring” ISSN 2248-9622 International Journal of Engineering Research and

Applications (IJERA) Vol. 2, Issue 5, September- October 2012, pp.692-697.

viii. M. M. Patunkar, D. R. Dolas “Modelling and Analysis of Composite Leaf Spring under the Static Load Condition by using FEA” International

Journal of Mechanical and Industrial Engineering, Vol.1, Issue 1, 2011.

ix. Ghodake A. P., Patil K.N. “Analysis of Steel and Composite Leaf Spring for Vehicle” IOSR Journal of Mechanical and Civil Engineering

(IOSR-JMCE) e-ISSN: 2278-1684 Vol.5, Issue 4 (Jan. - Feb. 2013), pp. 68-76.

x. B.Vijaya Lakshmi I. Satyanarayana “Static and Dynamic analysis on Composite Leaf Spring in Heavy Vehicle” International Journal of Advanced

Engineering Research and Studies (IJAERS) ISSN 2249–8974, Vol.II, Issue I,

Oct-Dec.2012, pp.80-84. xi. B. Raghu Kumar, R. Vijaya Prakash and N. Ramesh “Static Analysis

of Mono Leaf Spring with different Composite Materials” ISSN 2141-2383

Journal of Mechanical Engineering Research Vol. 5(2), 2013, pp. 32-37. xii. Karuppaiah N, Sujatha C, and Ramamurti V, “Numerical Analysis of

Vibration Response in a Light Passenger Vehicle”, IMAC-XX, Vol.4753, 2002.

xiii. Ramamurti V and Sujatha C, “Bus Vibration Study-Theoretical response analysis and experimental verification”, International Journal of

Vehicle Design, Vol. 11(4/5), 1990, pp 401-409. xiv. Manjunath K, “Random Vibration Analysis of a bus structure using

FEM”, Submitted to VTU in partial fulfillment of Master of Technology, 2002-

2003. xv. Rangaswamy T and Vijayarangan S, “Optimal Sizing and Stacking

Sequence of Composite Drive Shafts”, Journal of Materials science, Vol.11,

No.2, 2005, pp. 133-139.

Documents

Vibration Analysis of Composite Leaf Spring for a Light