Global journal 72

www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016

ISSN: - 2349–283X

ANALYSIS OF STEEL LEAF SPRING OF LIGHT PASSENGER VEHICLE USING FEM DevendraSingh (AssistantProfessor) Department of Mechanical Engineering SRMUniversity,NCRCampus,Ghaziabad-201204India E-mail: devendrasingh@teachers.org ABSTRACT: The leaf spring used in automobile light passenger vehicle is analyzed using ANSYS 12.1.The finite element result showing stresses and deflection verified with existing analytical solutions. In the present work steel leaf spring is modeled in solid works 2009 and finally analysis is carried out using ANSYS 12.1 to predict the von-misses stresses and maximum deflection under the static condition.

Keywords: leaf spring, Finite element Method, Stress analysis

1. INTRODUCTION: Leaf springs are crucial suspension used on light passenger vehicle necessary to minimize the vertical vibrations impacts and bumps due to road irregularities and to create the comfort ride. Leaf springs are widely

design that is stressed and analyzed for specific results.

The leaf spring is analyzed for static strength and deflection using 3-Dfinite element analysis. The general purpose finite element software ANSYS is used for present study. The variation of bending stress and deflection values are predicted.

used for automobile and rail road suspensions. The leaf

2.DESIGN CALCULATION OF LEAF SPRING

spring should absorb the vertical vibrations and impacts

Consider the Leaf Spring is Cantilever Beam. So the Load acting on the each assembly of the Leaf Spring is acted on the two ends of the Leaf Spring. Load acted on the Leaf Spring is divided by the two because of consideration of the Cantilever Beam.

due to road irregularities by means of vibrations in the spring deflection so, that the potential energy is stored in spring as strain energy and released slowly so increasing the energy storing capabilities of a leaf spring and ensure a more compliant suspension system. The

Material of Leaf Spring:- 50Cr1V23,

amount of elastic energy that can be stored by a leaf

Composition of material is 0.45%C, 0.1-0.3% Si, 0.6-

spring volume unit [6] is given by Eq. (1).

0.9%Mn and 0.9-1.2%Cr.

S=1/2 * σ2/E

Basic Requirement:-Maximum capacity: - 2850 Kg.

----------------------- (1)

Where σ is the maximum allowable stress induced into the spring and E is the modulus of elasticity, both in the longitudinal direction. Considering that the dominant loading on leaf spring is vertical force. Three dimensional finite element analysis of the leaf spring consists of a computer model or

:- 2850 x 9.81 :- 27958.5N Material of the Leaf Spring is 50Cr1V23.

Properties of the Material are as under:-

© Virtu and Foi. Betterment of Humanity

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www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016 Tensile Strength ( σt ) :- 190 – 240 Kgf/mm2

ISSN: - 2349–283X Length of the Leaf Spring are as under:L6:- [ {( 2 x L1 ) / ( n – 1 )} x 1 ] + l (ineffective length)

:- 1900 – 2400 N/mm2

:- [ {( 2 x 575 ) / ( 6 – 1 )} x 1 ] + 110.00

Yield Strength ( σy ) :- 180 Kgf/mm2

:- 340.00mm

:- 1800 N/mm2

Similarly,

Modulus of Elasticity ( E ) :- 200000 N/mm2

L5

BHN :- 500 – 580 HB with hardened and tempered

L4

By considering the factor of safety for the safety purpose

L3

of the Leaf Spring 1.5 for automobile leaf spring. So the allowable stress for the Leaf Spring is as under:-

L2

:570.00mm :800.00mm :1030.00mm :- 1260mm

But first and second Leaf Spring are Full Length leaves.

Tensile Strength ( σt ) :- 1900 / 1.5

And first length leave is known as a Master leaves.

:- 1266.66 N/mm2 Yield Strength ( σy )

Length of the Master Leaves calculated is as under:Length of Master Leave: - 2 x L1 + π x ( t + d ) x 2

:- 1800 /1.5

:- 1260 + π x ( 7.5 + 30.00 ) x 2

: - 1200 N/mm2

:- 1496.00N/mm2

Bending stress generated in the Leaf Spring are as under:-

1. MODELLING AND STATIC FEM ANALYSIS OF LEAF SPRING

σb :- ( 6x W x L ) / ( n x b x t2 )

MODELLING OF LEAF SPRING

σb :- ( 6 x 6989.625 x 575.00 ) / ( 6 x 60.00 x 7.52 ) σb :- 1190.825 N/mm2 So, the stress generated in the Leaf Spring is lower then the Allowable Design Stress. So Design is safe.

Modelling of Leaf Spring is performed in Solid works 2009.

Procedure of Modelling Leaf Spring is as follows:There is different procedure available for modelling of leaf spring. Here we utilize divisional method of generation of Parabolic Leaf Spring.

Deflection generated in the Assembly of Leaf Spring are as under :y :- (6 x W x L3) / (n x E x b x t3) y :- ( 6 x 6989.625 x 5753 ) / ( 6x200000 x 60 x 7.53) y :112.49mm

1) Create below sketch with the help of Leaf Spring length and Camber. Divide Leaf Spring length and camber into equal division and draw a spline which passes through intersection of Camber and length division which shows as under.

Calculation of the Length of Leaves are as under :Ineffective length of the Leaf Spring ( l ) :- 110.00mm © Virtu and Foi. Betterment of Humanity

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www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016

ISSN: - 2349–283X

2) Extrude above sketch to Leaf Spring Width to create one leaf.

4) Assign Material to Six Leaves of Leaf Spring.

3) Same way Create Six Leafs for generating Leaf Spring of Cruiser.

5) Define Contact between leaves of Leaf Spring.

Contact Type:- No Separation

STATIC FEA ANALYSIS OF LEAF SPRING 1) After Creating Solid Model of Steel Leaf Spring in SOLIDWORKS 2009. Save that model in *.IGES format.

2) Import above 3D Model in ANSYS Workbench Static Structural Module for Static FEM Analysis.

3) Create Leaf Spring Material 50Cr1V23 © Virtu and Foi. Betterment of Humanity

6)

Create meshing of Leaf Spring.

Type of Meshing: - 3D

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www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016

ISSN: - 2349–283X

Type of Elements:- Brick

Define Force

Number of Nodes:- 3517

9) Get Results

Number of Elements:- 403

7)

Apply Boundary Condition

Define Fixed Support.

9 10) Result of Analysis Von-Mises Stresses Contour Maximum Deflection Contour

8)

Run Analysis.

4) RESULTS, DISCUSSION AND CONCLUSION The project illustrates the importance of analytical and Microanalysis. FEM analysis is done in ANSYS12.1 and project shows the importance of static analysis. Below Table Shows that Static FE Analysis Fairly matches with the Analytical results with but it also shows that Static FE Analytical Results underestimate the results.

For the optimization of Leaf Spring, Accurate prediction of stresses and deflection is necessary © Virtu and Foi. Betterment of Humanity

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www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016

ISSN: - 2349–283X Acknowledgement

RESULT TABLE

Analytical Results

Static Percentage Analysis FE Variation Results

VonMisses Stresses

1190.825

1140.2

4.251254382

Maximum Deflection

112.49

109.32

2.818028269

I would like to thank Asst. Prof Pramod Patel and Asst.

Prof Ashish Kumar for their valuable guidance and supporting this research

References 1) Rajendra, I., Vijayarangan, S.Optimum design of a composite leaf spring using Genetic algorithms Int.Jr.of computer and structures 79 2001:pp.1121-1129.

2) Rajendra,I.,Vijayarangan, S.Optimum design and analysis of composite leaf spring journal of institute of engineers India 82 2002:pp180-187.

3) Senthil Kumar and vijayarangan,”Analytical and experimental studies on fatigue life prediction of steel leaf spring and composite leaf spring using life data analysis ”ISSN 1392 1320 material science Vil.13 No.2 2007 4) SAE Design manual for leaf spring.

5) Ansys 12.1 for FEA Analysis 6) Textbook of machine design by R.S. Khurmi and J.K. Gupta.

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