Design and Structural Analysis of Steering Knuckle for An Electric All-Terrain Vehicle – E Baja

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Design and Structural Analysis of Steering Knuckle for An Electric All-Terrain Vehicle – E Baja

1. Jukanti Sandeep Reddy , 2. S Sai Dheeraj , 3. S Upendar Reddy

Department of Mechanical Engineering, Hindustan institute of Technology and sciences Chennai, India 603103

Abstract:- Steering knuckle is a component which is used as a connection between the wheels , suspension and braking system and also helps the wheels of the vehicle to turned in the required direction. The reason for this research paper is to design a knuckle which has low weight so that vehicle unsprung mass can be reduced. Design is an important factor in product development cycle.By the decrease of the unsprung mass of the vehicle the riding characteristics of the vehicle can be improved.The strength and durability of the component is maintained by the usage of the ligt weight aluminium T6 7075 rather than the grey cast iron and mild steel. This study involve two steps.First step is to design the component and second step is to do the finite element analysis to find the stresses induced and to know the deformation of the component. The design is done with the help of the Catia V5 and the analysis is done with the help of Ansys work bench 15.0.

Key Words : Steering knuckle, All terain vehicle, FEA, Bump ,Cornering, Braking, Al-7075-T6

INTRODUCTION

Steering knuckle is one of the important component in the vehicle which is used to provide the front wheels to turn in the requried direction. Knuckle converts the linear motion of the tie rod to angular motion of the stub axle.Knuckle is used to join the components like brake caliper , tie rods ,upper and lower ball joints.Knuckle design can be done into two types based up on the type suspension we are using either the mach-person struct or the double wish bone suspension. A steering knuckle is designed in a such a way that it can be capable to with stand the forces and torqes acting on it due to bumps ,braking,acceleration,and steering action.To obtain the good riding chracteristics of a vehicle the unsprung mass of the vehicle should to be reduced.Nearly 90 % of the unsprung mass contains the wheel assembly. So our goal is to design a knuckle which has a weight as low as possible.For the design of knuckle we have to maily consider parameters like king pin inclination, caster angle and the distance between the upper and lower ball joints.As atv vehicle runs on the bumpy roads good factor of safety is required for the knuckle component to withstand those conditions

RESEARCH PROCEDURE

1 . Study of knuckle to know the different parameters affecting it

1 . Study of knuckle to know the different parameters affecting it

2 . Slection of material

2 . Slection of material

3 . Designing the components

3 . Designing the components

4 . Meshing the model

4 . Meshing the model

5 . Applying the various loads acting on the component

5 . Applying the various loads acting on the component

6 . Stress analysis

6 . Stress analysis

7 . Optimization

7 . Optimization

8 . Results

8 . Results

PROPERTIES OF GREY CAST IRON,MILD STEEL AND ALUMINIUM 7075 T6

  1. MILD STEEL

    PYSICAL PROPERTIES

    QUANTITY

    VALUE

    UNIT

    Density

    7.87

    g/cm3

    MECHANICAL PROPERTIES

    QUANTITY

    VALUE

    UNIT

    Tensile strength, Ultimate

    370

    Mpa

    Tensile strength,yield

    370

    Mpa

    Youngs modulus

    205

    Gpa

    Poisson ratio

    0.290

  2. Cast Iron

    PHYSICAL PROPERTIES

    QUQNTITY

    VALUE

    UNIT

    Density

    7.87

    g/cm3

    MECHANICAL PROPERTIES

    QUQNTITY

    VALUE

    UNIT

    Tensile strength, Ultimate

    520-570

    Mpa

    Tensile strength,yield

    540

    Mpa

    Youngs modulus

    200

    Gpa

    Poisson ratio

    0.291

  3. ALUMINIUM 7075 T6

ELEMENT

Cu

Mn

Si

Cr

Mg

Ti

Zn

Al

% WEIHT

1.2-2

Max 0.3

0.4 Max

0.18-0.28

2.1-2.9

0.2 MAX

5.1-6.1

87.1-914

PHYSICAL PROPERTIES

Properties

VALUE

UNIT

Density

2.81

g/cm3

Tensile strength, Ultimate

115

Mpa

Hardness (HB500)

30

60

Elastic modulus

70-80

Gpa

Poisson ratio

0.33

Load calculations:

Total weight of the vehicle : 380kg

Weight on front portion of the vehicle=50%=190kg. Weight on the rear portion of the vehicle=50%=190kg. Weight on the one wheel=(190/2)=95kg.

Loading types:

Bump condition =3G=(3*9.81*95)=2795.85N. Cornering condition=3G=(3*9.81*95)=2795.85N.

Breaking force=1.5G=(1.5*9.81*95)=1397.92

Force acting on each brake mount=(1397.92/2)=698.96N Distance from knuckle centre to brake mount=95mm

Moment acting on each mount=(brake force per mount *perpendicular distance)

=(698.96*95)=66401.43N-mm

Moment acting on upper brake mounting point=66401.43N-mm Moment acting on lower brake mounting point=66401.43N-mm

LOADING CONDITIONS

In the design of the knuckle the upper and lower A arm mounting points and the steering arm are fixed .Bump load is given along the Y axis, cornering force is given along the Z axis and the braking force is applied on X axis on the brake mounting points

M0DELLING

In this research paper the model is prepared using the catia v5 software . After designing the model the file is saved in IGS format and then it is imported to ansys for analysis the model by applying the various loads . By the help of the ansys software the structial analysis is done and results were obtained differently for the three different materials . Then by comparing the results obtained for different materials , the materials which has low weight and good factor of safety is selected and with this material the knuckle model is manufacture

MESH MODEL

The errors in the geometry is corrected and the model is meshed . The type of mesh selected is fine mesh

  1. ALUMINIUM T6 7075

    fig:1 mesh model of the knuckle

    The following figures shows the stress destribution and the total deformation of the AL T6 7075 material

    fig :2 Equivalent stess distribution fig:3 Total deformation

    1. Maximum stress distribution :160.96 Mpa

    2. Maximum total deformation :4.582 mm 3 Total ultimate tenile strength :572 Mpa

2 Mild steel

The following figures shows the stress destribution and the total deformation of the mild steel material

fig:4 Equivalent stess distribution

  1. Maximum stress distribution :164.87 Mpa

  2. Maximum total deformation :0.17716 mm 3 Total ultimate tensile strength :460 Mpa

    fig:5 Total deformation

  3. Cast iron

The following figures shows the stress destribution and the total deformation of the cast iron material

fig:6 Equivalent stess distribution fig:7 Total deformation

  1. Maximum stress distribution :164.28 Mpa

  2. Maximum total deformation :0.32259 mm 3 Total ultimate tensile strength : 240 Mpa

    The factor of safety of all the three materials are calulated Factor of safety = ultimate tensile strength /working stresses 1 . For aluminium T6 7075 = 572/160.96 =3.5

    2 . For mild steel = 460/164.87 =2.7

    3 . For cast iron = 240/164.28 =1.4

    RESULT

    CONCLUSION

    From the above analysis report when compared to all three materials aluminium T6 7075 material has the higher factor of safety . when compared to the weight al T6 7075 material has low weight than cast iron and mild steel . So we prefer to the aluminium T6 material for the manufacturing of the steering knuckle

    REFERENCES

    1. A text book of Machine Design by Khurmi and Gupta

    2. A text book of Design of Machine Element by V.B. Bhandari, Tata McGraw Hill Education Pvt Ltd.

    3. Kulkarni, V. R. and Tambe, A. G.,(2013): Optimization and Finite Element Analysis of Steering Knuckle, Altair Technology Conference.

    4. Viraj R. Kulkarni and Amey G. Tambe, Optimization and Finite Element Analysis of Steering Knuckle, Altair technology conference 2013

    5. P. Tagade, Anil R. Sahu and H. C. Kutarmare : Optimization and Finite Element Analysis of Steering Knuckle ;International Journal of Computer Applications (0975 8887)

    6. B. Bolles, Advanced Race Car Chassis Technology vol. HP1562: HP Trade, 2010.

    7. Gillespie, Thomas d; Fundamentals of vehicle dynamics, Warren dale, pa: society of automotive engineers Inc., year 1999

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