FATIGUE ANALYSIS OF AN AUTOMOBILE WHEEL RIM

FATIGUE ANALYSIS OF AN AUTOMOBILE WHEEL RIM

Sayed Noamanul Haque1 & Krupal Pawar2

M.Tech (Design), Research Scholar, Sandip University, Nashik1

Assistant Professor, Sandip University, Nashik2

Abstract: Automotive wheel is very critical component in the vehicle which has to meet the strict

requirements of driving safety. It is very vital for durability assessment of mechanical components early in the

design phase. Traditionally, this has been performed mainly with prototype tests like dynamic cornering fatigue

test, radial fatigue test etc. But it is difficult to understand fatigue failure mechanisms various loading

conditions. The new designed wheel is tested in the lab for its fatigue life through an accelerated fatigue test

before the actual production starts. However, a physical prototype test time takes at least 7 days and an

average design period is 6 months or more depending on the requirement, it is very time consuming process. At

the same time, because steel wheel is designed for variation in style and has very complex shape, it is difficult to

assess fatigue life by using analytical methods. Every wheel have to pass Dynamic cornering fatigue test. In this

paper we are studying Fatigue analysis of an Automobile rim using FEA software on DCFT, the data which will

be used to optimize the wheel on weight or mass base criteria with different materials. Here we have used

Aluminum alloy and Magnesium alloy to replace the steel wheels.

Keywords: Automobile wheel Rim, Dynamic Cornering Fatigue Test, FEA software.

1. INTRODUCTION

Wheel producers are using new materials and manufacturing technologies in order to

improve the wheel’s aesthetic appearance and design. Steel wheels are widely used for

wheels due to their excellent properties, such as lightweight, good forge ability, high wear

resistance and mechanical strength. Ensuring the reliability and safety of automobile wheel

rim is very important [1]. Analysis of the rims consists of numerically analyzing the stress

levels that rims experience during operating conditions. The load bearing capacity of the

bolt pattern will be evaluated for conditions of severe loading. The finite element (FE)

method is implemented for all automobile wheel rim analysis. The reliability of FEA

approach is based on their previous experience in fatigue analysis studies .The magnitude

of the static load and pressure contributes to increasing the stresses on the rim components.

The traditional fatigue test of wheel depend on the radial and cornering fatigue tests cannot

simulate the real stress state of wheel well. In this paper, a new method is proposed to

calculate the fatigue life of commercial vehicle wheel, in which the finite element model of

biaxial wheel fatigue test rig is established based on the standard so fEUWAES3.23 and

SAEJ2562, and the simulation of biaxial wheel test and fatigue life estimation considering

the effects of tire and wheel camber is performed by applying the whole load spectrum

specified inES3.23 to the wheel.[1]The (FEM) results of a pavement structure are wont to

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calculate how stress state at the layer interface varies during the passage of a wheel over the

surface on road and to qualify the reasonability of existing dynamic tests wont to

characterize interface shear behaviour. FEM are compared with stress undergone by

specimens tested with the foremost common devices like guillotine or inclined. the

important stress state may only be reproduced with a device that can independently manage

normal pressure and shear [2]. The proposed a computational methodology to simulate

wheel dynamic cornering fatigue test and estimate its’ multi-axial fatigue life. The strain

states of wheel are basically biaxial tensile and compression normal stresses during the

prototype test, which indicates that the fatigue crack may occur first in the circumferential

direction of steel wheel [9].

In this paper it is very vital for durability assessment of mechanical components early in the

design phase. Traditionally, this has been performed mainly with prototype tests like

dynamic cornering fatigue test, radial fatigue test etc. But it is difficult to understand

fatigue failure mechanisms various loading conditions. The new designed wheel is tested in

the lab for its fatigue life through an accelerated fatigue test before the actual production

starts. In this paper we are studying Fatigue analysis of an Automobile rim using FEA

software on DCFT, the data which will be used to optimize the wheel on weight or mass

base criteria with different materials. Here we have used Aluminum alloy and Magnesium

alloy to replace the steel wheels.

2.OBJECTIVE

The main objective of the work is to replace heavy steel wheel by light alloy wheel. For

this we are using FEA method. Two designs are available and two materials are available.

Aluminum alloy and Magnesium alloy. The Rim must pass Dynamic Cornering Fatigue

Test.

3.METHODOLOGY

Before starting analysis it is to understand current process. Literature review was dispensed

to understand with past work dispensed in field stress analysis of Wheel Rim. To validate

the solution following methodology was adopted.

1. Experimental Method 2.Finite Element Method 3.Comparison of above two

methods

According to standards Rim should pass following tests:

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1. Dynamic Cornering Fatigue Test.

4. PARAMETERS

4.1Number of Designs

1.Design No.1-D01

2.Design No.2-D02

4.2 Maximum Bending Moment

Bending Moment is calculated as follows:

The bending moment is calculated as follows

B.M=FRd+FLR (1)

= FRd+µFRR (2)

Where,

FR=Radial force acting on the wheel=1150 Kg

d=wheel offset=0.252

µ=Coefficient of friction between ground and tire=0.7

R=Maximum allowable Radius of statically loaded tire mounted on the wheel=0.250 m

B.M=488.75 Kgm =4795.64 Nm =4800 Nm.

4.3Materials Used

1. Aluminum Alloy-M1

2. Magnesium Alloy-M2

4.4 Conditions of Moments Applied

1. Moment Applied on Hub Bolt Region- C1

2. Moment Applied on Complete Hub - C2

4.5 Experimentation Plan

Compounding all parameters Experiment Plan is designed as follows:

For Each level of experiment 4 samples will be tested. Therefore total samples

checked will be = No. of experiments X Samples= 8X4=32 samples to be tested and

Moment applied will be 4800 Nm.

Table No. 1.1 Experimentation Plan

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Sr.

No.

Design No. Material Condition

1 D1 M1 C1

2 D2 M1 C1

3 D1 M2 C1

4 D2 M2 C1

5 D1 M1 C2

6 D2 M1 C2

7 D1 M2 C2

8 D2 M2 C2

5. CORNERING FATIGUE TEST

For the aim of validation the physical known as cornering fatigue test is dispensed

and discussed below.

5.1Dynamic Cornering Fatigue Test Setup for Experimentation

The DCFT is a standard wheel test, which applies cornering loads to the auto rim.

Fig 5.1 shows the test setup in where the testing rim is mounted on the rotating

table, the moment applying arm is fixed to the wheel external mounting plate with

the bolts and a moment is applied at the end of the moment arm by the

moment/force actuator and bearing, thus applying a rotating bending moment to the

wheel. If the rim passes the DCFT, it's an good chance of passing all other

remaining fatigue tests.

Figure No. 1.1 Basic Dynamic Cornering Fatigue Test System

6. FINITE ELEMENT ANALYSIS OF WHEEL RIM

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6.1Step by Step Analysis

6.1.1 Geometric Modeling

Figure 1.2 Geometric Model Design 1

This modeling is done in CATIA software and saved as ‘STEP’ format and

imported to ANSYS for further analysis.

6.1.2 Wheel Meshing

Figure.No.1.3 Meshing of Design 2

6.1.3 Loads and Boundary Conditions

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The applications of moments are at 2 geometries:

1. Mounting Area

2. Rim Hub

and as in actual test rim is fixed we will fix to Wheel Rim Structure.

Figure 1.4 Fixed Support Design 1

MOMENT APPLIED

Figure 1.5 Moments Applied Case 1 Design 1

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Figure No. 1.6 Moment Applied Case 2 Design 2

For optimization Purpose we will select these parameters and check the best

combination for Dynamic cornering fatigue test.

Sample Result Plots: Experiment No.1

Figure No. 1.7 Equivalent Stress

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Figure No. 1.8 Equivalent Strain

Figure No. 1.9 Total Deformation

7. RESULT AND DISCUSSIONFROM FEA PLOTS

Table No.1.2 Safe Test Chart

Exp. No. Eq. Stress(X 108 Pa) Eq. Strain Total Def. (m) Remark

1 1.55 0.00164 0.000303 SAFE

2 2.06 0.00291 0.000338 SAFE

3 1.157 0.00260 0.000480 SAFE

4 2.049 0.00457 0.000533 FAIL

5 1.182 0.00168 0.000304 SAFE

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6 2.049 0.00290 0.000300 SAFE

7 1.180 0.00265 0.000480 SAFE

8 2.040 0.00455 0.000534 FAIL

Table No. 1.3 Outcome from Finite Element Analysis

From above analysis it is clear that Experiment no.4 have Maximum equivalent stress 2.049

X108 also Experiment No.8 have Maximum equivalent stress 2.040 X108 which is greater

than Tensile Strength of Magnesium 1.93X108 so these two combination Fails under given

boundary conditions. Whereas experiments 1, 2, 3,5,6,7 are safe. It is clear that experiment

number 4 and 8 are associated with design number 2 is unsafe. Also Design 1 is safe with

both materials therefore design 1 is checked with AL alloy and Mg alloy on weight or mass

basis. Mg alloy rim have less weight which is the optimize level.

8. CONCLUSION

A Multi-objective analysis concept is carried out to optimize the weight of the Rim. Also to

determine whether the moment is applied at mounting holes or at Hub also. Work is carried

out in steps by step manner. We found that:

1. Design 1 is suitable for the vehicle considered.

2. Design 2 has some issues related to strength and moment carrying capacity.

3. Magnesium alloy is suitable with Design 1 & It’s weighs only 6.39 Kgs.

4. Earlier rim weighs was 15.3 Kgs.

5. So reduction in mass is 15.3-6.39 =8.91 Kg.

Expt. No Design

No. Material

Mass

(Kg.) Case Remark

1 D1 Al Alloy 9.84 C1


3 D1 Mg Alloy 6.39 C1 OPTIMIZE LEVEL



7 D1 Mg Alloy 6.39 C2 OPTIMIZE LEVEL

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Acknowledgement

I am very thankful to Dr.K.P.Pawar, Assistant Professor, Sandip University, Nashik for their guidance and Prof. Dr. A.Gangele, Head of Mechanical Engineering, School of Engineering & Technology, Sandip University, Nashik for their technical support.

REFERENCES

[1] Wan, X., Shan, Y., Liu, X., Wang, H., & Wang, J. (2016). Simulation of biaxial wheel test and fatigue life estimation considering the influence of tire and wheel camber. Advances in Engineering Software, 92, 57-64.

[2] D’Andrea, A., &Tozzo, C. (2016). Interface stress state in the most common shear tests. Construction and Building Materials, 107, 341-355.

[3] Irastorza-Landa, A., Van Swygenhoven, H., Van Petegem, S., Grilli, N., Bollhalder, A., Brandstetter, S., &Grolimund, D. (2016). Following dislocation patterning during fatigue. ActaMaterialia, 112, 184-193.

[4] Song, W., Woods, J. L., Davis, R. T., Offutt, J. K., Bellis, E. P., Handler, E. S., ... & Stone, T. W. (2015). Failure analysis and simulation evaluation of an AL 6061 alloy wheel hub. Journal of Failure Analysis and Prevention, 15(4), 521-533.

[5] Nejad, R. M., Farhangdoost, K., &Shariati, M. (2015). Numerical study on fatigue crack growth in railway wheels under the influence of residual stresses. Engineering Failure Analysis, 52, 75-89.

[6] Fang, G., Gao, W. R., & Zhang, X. G. (2015). Finite element simulation and experiment verification of rolling forming for the truck wheel rim. International Journal of Precision Engineering and Manufacturing, 16(7), 1509-1515.

[7] Li, Z., DiCecco, S., Altenhof, W., Thomas, M., Banting, R., & Hu, H. (2014). Stress and fatigue life analyses of a five-piece rim and the proposed optimization with a two-piece rim. Journal of Terramechanics, 52, 31-45.

[8] Weishaupt, E. R., Stevenson, M. E., & Sprague, J. K. (2014). Overload Fracture of Cast Aluminum Wheel. Journal of Failure Analysis and Prevention, 14(6), 702-706.

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FATIGUE ANALYSIS OF AN AUTOMOBILE WHEEL RIM