impact analysis of automobile bumper by using ansys work...

Impact Analysis of Automobile Bumper by using ANSYS Work

Bench

Ch. Raghu Babu1, Dr. Suresh J S2 1, PG Scholar, Department of Mechanical Engineering

2 Professor and HOD, Department of Mechanical Engineering

Ramachandra College of engineering, Eluru, West Godavari (Dist), AP, India. [email protected]

Abstract

Now a day’s bumper is used in vehicle which directly connected to chassis of vehicle. So that

when accidents are happened the force that transfer to other parts of vehicle through linkage.

There are no other supports to absorb that impact forces. So there is a design need to absorb

impact forces. For that reason here designed a new bumper system by Stiffeners. Stiffeners are

used to minimize the impact of accidents and it will resists or absorbs impact forces. The

objective of present study is to design and optimization of Automobile Bumper to avoid crashes

and for the safety of passengers and pedestrians so for many Authors have worked on

Automobile Bumper crash analysis and very few of them have focused on optimization of the

strength and weight. In our study we are on focused on impact analysis of automobile bumper

with high strength to weight ratio materials by using Ansys Workbench.

In this project, the new bumper system is designed using CREO and structural analysis is

done in ANSYS Workbench. For structural analysis of the bumper, here we made impact

analysis on existing (Maruti Alto) bumper with standard structure and honey comb structure at 9

different speeds such as 10km/hrto 90km/hr with 10Km/hr Intervalsby comparing with ABS

Plastic (Existed) to improve the overall performance of bumper.

Keywords- Bumper, Impact Forces, Stiffeners, CREO, ANSYS, Structural Analysis, ABS Plastic

1. INTRODUCTION

1.1 Bumper

A bumper is a structure attached to or integrated with the front and rear ends of a motor

vehicle, to absorb impact in a minor collision, ideally minimizing repair costs. Bumpers also

have two safety functions: minimizing height mismatches between vehicles, and protecting

pedestrians from injury. British inventor Frederick Simms invented bumpers in 1901.

Science, Technology and Development

Volume IX Issue VII JULY 2020

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mailto:[email protected]

1.2History

Every day Car accidents are happening. Most troublesome situations are occurred to the

drivers that they can avoid such. The statistics shows that ten thousand dead and hundreds of

thousands to million wounded each year. Hence, improvement in the safety of automobiles is

prerequisite to decrease the numbers of accidents. Automotive bumper system is one of the key

systems in passenger cars. Bumper systems are designed to prevent or reduce physical damage to

the front or rear ends of passenger motor vehicles in collision condition. It protects the hood,

trunk, grill, fuel, exhaust and cooling system as well as safety related equipment such as parking

lights, headlamps and taillights, etc. A good design of car bumper must provide safety for

passengers and should have low weight. The function of automotive bumpers has changed

considerably over the past 70 years. The later performance is achieved by a combination of

careful design, material selection to obtain a particular balance of stiffness, strength and energy

absorption. Stiffness and Energy absorption are essential criterion. Stiffness is important because

vehicle design consideration limits the packaging space for the bumper design to deform under

load and Energy absorption is important because bumper must limit the amount of the impact

force transmitted to the surrounding rails and vehicle frame. Automotive bumper plays a very

important role in absorbing impact energy (original purpose of safety) and styling stand

point/aesthetic purpose. Now a day, automotive industry concentrates on optimization of weight

and safety.

Fig.-1 Chrome plated front bumper on a 1958 Ford Taunus

In 1971, the US National Highway Traffic Safety Administration (NHTSA) issued the

country's first regulation applicable to passenger car bumpers. Federal Motor Vehicle Safety

Standard No. 215 (FMVSS 215), "Exterior Protection," took effect on 1 September 1972— when

most automakers would begin producing their model year 1973 vehicles.



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1.3 Types of Bumpers

Standard Bumper

Deep Drop Bumper

Roll Pan Bumper

Step Bumper

Tube Bumper

1.3.1 Standard Bumper

Standard bumper is a structure attached to or integrated with the front and rear ends of a

motor vehicle, to absorb impact in a minor collision, ideally minimizing repair costs....Bumpers

ideally minimize height mismatches between vehicles and protect pedestrians from injury.

1.3.2 Deep Drop Bumper

This type of bumper is typically found on older trucks and is usually chrome plated. Deep

drop bumpers have a heavy-duty towing capacity and a lower ball height than a step bumper.

The drop from the bottom of the frame is usually 10 or 12 inches.

1.3.3 Roll Pan Bumper

Roll pan bumpers are typically found on custom compact trucks. The trailer hitches

available will sit in the middle, behind the bumper.

1.3.4 Step Bumper

This type of bumper is typically found on trucks, vans and SUVs. The small cut-out in

the centre looks like a step. This bumper also has holes for hitch balls and can be used to tow

lightweight trailers.

1.3.5 Tube Bumper: This type of bumper is typically found on jeeps.

Vehicle damageability would be improved in both these situations with taller front and

rear bumper beams. Real world claims data also show a significant number or crashes in which

damage is limited to the vehicle corners. Vehicle bumpers should prevent or limit much of the

damage sustained in these minor crashes. However, many vehicles do not have bumper

reinforcement beams that extend laterally much beyond the frame rails, leaving expensive

vehicle components such as headlamps and fenders (wings) unprotected.



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1. Geometry – vehicle bumpers need to be positioned at common heights from the

ground and extend laterally to the corners in order to properly engage other vehicles in low speed

crashes.

2. Stability – vehicle bumpers need to be tall and wide enough to remain engaged with

the bumpers of other vehicles despite vehicle motion due to loading, braking, etc.

1.4 Physics

Bumpers offer protection to other vehicle components by dissipating the kinetic energy

generated by an impact. This energy is a function of vehicle mass and velocity squared. The

kinetic energy is equal to 1/2 the product of the mass and the square of the speed. In formula

form:

𝐸𝑘 =1

2𝑀𝑣2

A bumper that protects vehicle components from damage at 5 miles per hour must be four times

stronger than a bumper that protects at 2.5 miles per hour, with the collision energy dissipation

concentrated at the extreme front and rear of the vehicle. Small increases in bumper protection

can lead to weight gain and loss of fuel efficiency.

2.LITERATURE REVIEW

[1]MAREK MAzuRKIEwrcz (1987), discussed on, In the United States, Federal

regulation FMVSS 215 (General guide for substantiation of compliance with FMVSS 214 and

215 CFR 581: Bumper Standard, pp. 9-81) requires that impact data of the front and rear

bumpers of cars be furnished for each make of vehicle. In this paper, the crash data of two

bumper beams are analysed by simulated computer models using the ABAQUS (Hibbitt,

Karlsson and Sorensen, Inc., Providence, RI, Version 4-S-171B) program. The salient feature of

the automatic time increment &ion scheme is used. Inelastic large deformation is considered.

Although sectional properties of the two beams and the initial impact condition are the same, the

technique used in selecting convergent tolerant is quite different due to the differences in

configuration. With due consideration good convergence can be achieved in less than 100 time

increments. Economically this compares very favourably to the actual testing during the initial

development process. The merits of crash simulation study are twofold: (I) providing economical



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evaluation of bumper capability; and (ii) serving to establish methods for comparing one bumper

to another for initial development purposes.

[2] Pradeep Kumar Uddandapu (2013), discussed on, Bumper is one of the main parts

which are used as protection for passengers from front and rear collision. The aim of this study

was to analyse and study the structure and material employed for car bumper in one of the car

manufacturer. In this study, the most important variables like material, structures, shapes and

impact conditions are studied for analysis of the bumper beam in order to improve the

crashworthiness during collision. The simulation of a bumper is characterized by impact

modelling using Pro/Engineer, impact analysis is done by SOILD WORKS according to the

speed that is 13.3 m sec-1 (48 km h-1) given in order to analyse the results. This speed is

according to regulations of Federal Motor Vehicle Safety Standards, FMVSS 208- Occupant

Crash Protection whereby the purpose and scope of this standard specifies requirements to afford

impact protection for passengers. In this research, analysis is done for speed according to

regulations and also by changing the speeds. Simulation using Finite Element Analysis software,

which is SOILD WORKS, was conducted. The material used for bumper is CARBON FIBER-

REINFORCED POLY-ETHER-IMIDE PEI and ABS Plastic.

[3] A.T. Beyene (2014), discussed on, Automobile bumper subsystem is the frontal and

rear structure of the vehicle that has the purpose of energy absorption during low velocity

impact. The main component of this subsystem is the transverse bumper beam, generally made

by steel. Design of vehicle subsystem for lightweight and for safety seems to lead the designer

toward opposite directions. Quite interesting solutions can be obtained with the use of composite

Materials. This paper is analysing some possible alternative solutions for the particular case of

the front and rear bumper.

[4]Bhavesh A. Bohra (2014), discussed on, an automobile's bumper is the front-most or

rear-most part, designed to allow the car to sustain an impact without damage to the vehicle's

safety systems. They are not capable of reducing injury to vehicle occupants in high-speed

impact. In this paper, review of the most important variables like material, structures, shapes and

impact conditions are studied for analysis of the bumper beam in order to improve the

crashworthiness during collision. More emphasis is given on selection of bumper material.



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3. MODELING AND ANALYSIS OF BUMPER

1. Study the literature related to bumper design and its performance improvement by referring

to books, journal papers and related manuals.

2. Obtaining design data of existing bumper model.

3.3D modelling of bumper model in ANSYS Workbench.

4. Selection of bumper material in accordance with design.

5. Theoretical calculation of impact force on bumper system as well as by using Ansys

Workbench

6. Analysis of part being designed using ANSYS Workbench

7. Calculation of Von- Moises stress and displacement and comparing the results obtained.

CREO

Creo Elements is a software application within the CAID/CAD/CAM/CAE category. Creo

Elements is a parametric, feature-based modelling architecture incorporated into a single

database philosophy with rule-based design capabilities. It provides in-depth control of complex

geometry, as exemplified by the trajpar parameter. The capabilities of the product can be split

into the three main headings of Engineering Design, Analysis and Manufacturing. This data is

then documented in a standard 2D production drawing or the 3D drawing standard ASME

Y14.41-2003.

Fig. - 3. Assembly of Bumper Fig. -4 Assembly of Bumper (Honeycomb structure)

Introduction about ANSYS15.0

Ansys Aim

ANSYS AIM demonstrates the vision of ANSYS 3D Multi physics Simulation in ANSYS

Workbench. In part, ANSYS AIM offers:

• An integrated single window display for end-to-end simulation, including geometry, meshing,

solution, post-processing and design point evaluation.



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• A guided simulation process through the use of templates and task-based windows.

• A common look-and-feel for fluid, structural, and thermal physics simulation technologies.

• Bi-directional CAD geometry access and integrated geometry preparation including reference

frames, model configuration, and suppression.

• Engineering topology creation for flow volume extraction.

• Automatic meshing based on engineering intent for fluid, structural, and thermal physics.

• A customizable user interface to select, create, and navigate operations.

• Consistent scripting and journaling throughout the simulation process.

• Full use of expressions for all model inputs.

• Ease of use actuated by pervasive reuse of data, parameterization.

• Results exploration combined with quantitative post-processing.

• Context-sensitive help and supporting documentation.

In addition to the ANSYS AIM documentation set, you can also reference the Workbench

Scripting Guide for information on using the journaling and scripting capabilities within ANSYS

AIM.

Deformations and von-mises stress diagrams



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Analytical Method

We considered Maruti Suzuki Alto Car Bumper for design

Mass of car =730kg

Mass of four passengers = 300kg i.e., 75kg each

Total Mass = 730 +300; m = 1030kg

F=m * a

Here, F – Net Force in N; m - Mass in Kg

a - Acceleration in m/s2

a = 𝒗−𝒖

𝒕

v- Final velocity (m/s); u- initial velocity (m/s); t- time (s)

Assumptions

1. Initial Velocity = 0 m/s

2. Time = 1 s



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For V = 10kmph

V = 10* 5

18

v = 2.77m/s

a =𝒗−𝒖

𝒕

a = 2.77−0

1

= 2.77 m/s

F=m*a

F=1030* 2.77

=2853N

For V = 20kmph

V = 20 * 5

18

v = 5.5 m/s

a =𝒗−𝒖

𝒕

a = 5.5−0

1

= 5.5m/s

F=m*a

F=1030* 5.5

F=5665 N

For V = 30Kmph

V = 30*5

18

V = 8.3 m/s

a = 𝒗−𝒖

𝒕

a = 8.3−0

1

= 8.3 m/s

F = m*a

F = 1030*8.3

F = 8549 N

For V = 40Kmph

V = 40*5

18

V = 11.1 m/s

a = 𝒗−𝒖

𝒕

a = 11.1−0

1

= 11.1 m/s

F = m*a

F = 1030*11.1

F = 11433 N

For v = 50Kmph

V = 50*5

18

V = 13.88 m/s

a = 𝒗−𝒖

𝒕

a = 13.88−0

1

= 13.88 m/s

F = m*a

F = 1030*13.88

F = 14296.4 N

For V = 60Kmph

V = 60*5

18

V = 16.66 m/s

a = 𝒗−𝒖

𝒕

a = 16.66−0

1

= 16.66 m/s

F = m*a



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F = 1030*16.66

F = 17159.8 N

For V = 70Kmph

V = 70*5

18

V = 19.44 m/s

a = 𝒗−𝒖

𝒕

a = 19.44−0

1

= 19.44 m/s

F = m*a

F = 1030*19.44

F = 20023.2

For V = 80Kmph

V = 80*5

18

V=22.22 m/s

a = 𝒗−𝒖

𝒕

a = 22.22−0

1

= 22.22 m/s

F = m*a

F = 1030*22.22

F = 22886.6 N

For V = 90Kmph

V = 90*5

18

V = 25 m/s

a = 𝒗−𝒖

𝒕

a = 25−0

1

= 25 m/s

F = m*a

F = 1030*25

F = 25750 N

4. RESULTS AND DISSCUSSION

Bumper with ABS Plastic at different speeds

Table-4.1 Bumper with ABS Plastic at different speeds

SNo. Cross Section Total

Deformation(mm) Von Mises Stresses(MPa)

SPEED

1

Existing Bumper 155.81 247.86 90KMPH

Honeycomb

Bumper

142.45 223.23

2


Honeycomb

Bumper

126.63 198.44

3


Honeycomb

Bumper

110.80 173.63

4


Honeycomb

Bumper

94.96 148.82

5


Honeycomb

Bumper

79.14 124.03



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6


Honeycomb

Bumper

63.31 99.21

7


Honeycomb

Bumper

47.48 74.41

8


Honeycomb

Bumper

31.65 49.60

9


Honeycomb

Bumper

15.82 24.80

5. CONCLUSIONS

1. The impact analysis is done at different speeds i.e.10kmph, 20kmph, 30kmph, 40kmph,

50kmph, 60kmph, 70mph, 80kmph & 90kmph for a bumper model for ABS plastic material with

existing model and honey comb model.

2. From the results, it is concluded that the honey comb model is having more strength i.e. less

deformation at different speeds than existing model.

REFERENCES

[1]MAREK MAzuRKIEwrcz and YEI LUNG TIEN, “CRASH SIMULATION OF

BUMPERS”, Vol 26. No. 5. pp. 141-741. 1987.

[2] Pradeep Kumar Uddandapu,“Impact Analysis on Car Bumper by varying speeds using

Materials ABS Plastic and Poly Ether Imide by Finite Element Analysis software Solid works”,

Vol.3, Issue.1, Jan-Feb. 2013 pp-391-395.

[3] A.T. Beyenea, E.G. Korichob, G. Belingardib, B. Martoranac, “Design and manufacturing

issues in the development of lightweight solution for a vehicle frontal bumper”, Procedia

Engineering 88 (2014) 77 – 84.

[4] Bhavesh A. Bohra, Prof. D. B.Pawar,”Comparative analysis of frontal car bumper during

impact”,Volume 3, Issue 12, December 2014.

[5] S Jeyanthi and J Janci Rani,“High velocity Impact Analysis of the Thermoplastic Bumpers in

Automobiles”,Vol. 73, January 2014, pp. 66-68 .

[6] Alen John, Nidhi M.B, “Modeling and Analysis of an Automotive Bumper Used for a Low

Passenger Vehicle”, Volume 15 Number 7 – Sep 2014.



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[7] KUSEKAR SAMBHAJI KASHINATH, CHUNGE ABHIJIT BALASAHEB, “REVIEW OF

DESIGN & ANALYSIS OF BUMPER BEAM IN LOW SPEED FRONTAL CRASHES”,

Volume- 2, Issue- 2, Feb.-2014.

[8] E. S. Roopesh, L. Bhaskara Rao,“Design and Analysis of an Automotive Frontal Bumper

Beam for Low-Speed Crashes”,Vol. 2 Issue 5, May – 2015.

[9] Anurag Dubey, Kumar Gautam Jha,“Technological Properties and Processing Technologies

of Composite Material: Design and Manufacturing of Composites”,Volume 29 Number 4 -

November 2015.

[10] R.Ranjithkumar, J.P.Ramesh,“MODELLING AND ANALYSIS OF A CAR BUMPER

USING VARIOUS MATERIALS BY FEA SOFTWARE”,April 2015.

[11] Rizul Kumar, Pranav Jain and Hemant Chouhan,“Low Velocity Impact Analysis on Bumper

Reinforcement Sections”,Volume 2, Number 2; April-June, 2015 pp. 76-78.

[12] Suresh Doddi, Dr. Maruthi B H, Dr. K. Channakeshavalu, Chandru.B.T,“Experimental-

Numerical Modal and Impact Analysis of Car Bumper”,Vol. 4 Issue 06, June-2015.



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