crash testing of cars

of 27CRASH TESTING OF CARS

SEMINAR REPORT

On

“CRASH TESTING OF CARS”

SubmittedTo

VISVESVARAYA TECHNOLOGICAL UNIVERSITYJNANA SANGAMA, BELGAUM

In the partial fulfillment of the requirement for the award of

The Degree

BACHELORS OF ENGINEERING In

MECHANICAL ENGINEERING

By

ARJUN B.A. (USN: 1RR09ME007)

Under the Guidance

Of

ANAND A.Asst Prof, M.E.Dept

RAJARAJESWARI COLLEGE OF ENGINEERINGDEPARTMENT OF MECHANICAL ENGINEERING

KUMBALAGODU, BENGALURU – 560074.

Dept. of Mechanical Engineering, RRCE


RAJARAJESWARI COLLEGE OF ENGINEERING #14, Ramohalli, Kumbalagodu, Mysore Road, Bengaluru - 560074.

(Affiliated to Visvesvaraya Technological University & Approved by AICTE, New Delhi)

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

Certified that the seminar work entitled, “CRASH TESTING OF CARS”, is a

bonafide work carried out in the department by ARJUN B.A. bearing USN:

1RR09ME007 in the partial fulfillment of the award of Bachelors of Engineering in

Mechanical Engineering of the Visvesvaraya Technological University (VTU),

Belgaum during the academic year 2012 - 2013. It is certified that all corrections /

suggestions indicated for internal assessment have been incorporated in the report

deposited in the departmental library. The seminar report has been approved as it satisfies

the academic requirements in respect of seminar work prescribed for the said degree.

Signature of the Guide Signature of the HOD

(ANAND A.) (Dr .SHANKAR REDDY)

Signature of the Principal

(Dr. M. S. BHAGYASHEKAR)



ACKNOWLEDGEMENT

I express my deep gratitude to almighty, the supreme

guide, for bestowing his blessings upon me in my entire endeavor.

I would express my heartfelt thanks to Dr. M.S. Bhagyashekar for his continuous support

and encouragement.

I would like to my sincere thanks to Dr. R. Shankar Reddy head of department of

Mechanical Engineering for all his assistance.

I wish to express my deep sense of gratitude to associate professor Anand .A Department

of Mechanical Engineering who guided throughout the seminar.

Finally, I would also like to thank all the lecturers of Mechanical department for their

valuable suggestions.

ARJUN B.A.

(USN: 1RR09ME007)



CONTENTS

ABSTRACT 5

INTRODUCTION 6

CRASH TEST DUMMIES 7

INSTRUMENTATION 10

ABSORPTION MECHANISM OF CRASH ENERGY 11

TYPES OF CRASH TEST 13

FRONTAL CRASH TESTING 13

FRONTAL OFFSET CRASH TESTING 14

SIDE CRASH TESTING 15

POLE CRASH TEST 16

SAFETY FEATURES 17

CASE STUDY:HONDA CR-V 19

IIHS FRONTAL CRASH TEST 20

IIHS FRONTAL OFFSET CRASH TEST 20

IIHS SIDE CRASH TEST 21

CRASH TEST RATINGS OF THE CARS BY NHTSA 22

NHTSA RATINGS FOR HONDA CR-V 23

CRASH TESTING CENTERS 25

CONCLUSIONS 26

BIBLIOGRAPHY 27



ABSTRACT

Driving a car is a high in itself, but safety is important too. Choosing a

safer car is very important to help prevent crashes and accidents. While cars are

becoming safer each year and fatality rates are falling, car crashes continue to be

one of the primary causes of death and injury. Thus, a thorough crash-testing

program is critical for the car makers (Carmakers themselves crash many

vehicles each year!) and has contributed significantly to the improving safety of

cars. Finding out whether newly improved safety features will perform

efficiently in an accident is the crash-testing facility’s responsibility. The idea is

to use every part of the vehicle in some way to save the occupant rather than the

vehicle. One would be amazed at how much thought and preparation goes into

making sure that safe cars are on the roads! In this paper I try to present all

about automotive crash testing – types, ratings, infrastructure required for

conducting tests, dummies and safety improvements.



INTRODUCTION

Every year, over 80,000 people die on Indian roads; every five road

accidents leave one dead. Yet, it's just a statistic, which hardly changes our

apathy towards road safety. Yes, road safeties are an unpleasant, boring subject,

but remember, it affects us all.

In recent years, cars have got much safer. One reason is that safety is

now a selling point in new cars. Frontal collisions, offset collisions, cars hitting

another vehicle or object in the traffic environment they are all tested using cars

of different sizes. Each vehicle's overall evaluation is based on three aspects of

performance — measurements of intrusion into the occupant compartment,

injury measures from a dummy positioned in the driver seat, and analysis of

slow-motion film to assess how well the restraint system controlled dummy

movement during the test.

The different aspects of the crash testing are discussed below: -

Infrastructure:

Crash testing needs infrastructure that could best simulate the

real road conditions, and capture the details required for crash analysis. The

basic infrastructure, any crash testing facility would need are:

A crash laboratory with an advanced high-tech crash barrier.

An outdoor test track that accommodates research for different weather

conditions.

Highly advanced crash simulator

Lighting system, this can provide up to 750,000 watts of illumination

without glare to film tests in slow motion. The resulting pictures must be

clear and dramatic.

Equipment for advanced component testing.

Supercomputers that crash tests non-existing cars. A system that propels

vehicles to impact, accelerating full-size pickups up to 50 mph.



CRASH TEST DUMMIES

Meet the Drivers

Hybrid III and Euro SID II have experienced dozens of crashes first-

hand. Their role is vital: the accident simulations rely on having a driver and

passenger aboard to provide a full picture of likely injuries in a crash, although

the pedestrian safety tests use simulated limbs to chart what happens in a

collision.

What Dummies Know

Dummies provide vital clues to what happens in a crash. Our limb- by-limb

anatomy guide explains how data is sourced.

Crash Test Dummies

The dummy's job is to simulate a human being during a crash, while

collecting data that would not be possible to collect from a human occupant. The

dummies come in different sizes and they are referred to by percentile and

gender. A dummy is built from materials that mimic the physiology of the

human body. For example, it has a spine made from alternating layers of metal

discs and rubber pads.

All crash tests are conducted using the same type of dummy (Nowadays the

most commonly used is the Hybrid III)

With the help of a number of specially built rig s, studies are being conducted to

discover what happens when parts of the human body collide with parts of the interior or

exterior of a car.

Crash test dummies are carefully calibrated and then positioned in vehicles to mimic

the movement of humans and record crash forces during the tests. Each complex dummy

includes 25 to 40 sensors to record the forces on various parts of the body.

Head



The head is made of aluminum and covered in rubber 'flesh'. Inside, three

accelerometers are set at right angles, each providing data on the forces and

accelerations to which the brain would be subjected in a crash

.

Neck

Features measuring devices to detect the bending, shear and tension

forces on the neck as the head is thrown forwards and backwards during the

impact.

Arm

Neither carries any instrumentation. In a crash test, the arms fly around in

an uncontrolled way, and although serious injuries are uncommon, it is difficult

to provide worthwhile protection against them.

Chest (front impact)

Hybrid Ill's steel ribs are fitted with equipment that records deflection of

the rib cage in the frontal impact. Injuries result if forces exerted on the chest,

such as from the seat belt are too great.

Chest (side impact)

The side-impact dummy, Euro SID II, has a different chest from the others and

three ribs are instrumented to record compression of the chest and the velocity of this

compression

Abdomen

Euro SID II is equipped with sensors to record forces likely to cause abdominal

injury.

Pelvis



Euro SID II has instruments fitted in its pelvic girdle. They record lateral

forces that may result in fractures or hip-joint dislocation.

Upper Leg

In Hybrid III, this area is made up of the pelvis, femur (thigh) and knee. Load cells

in the femur provide data in frontal impacts on likely injury to all sections, including the

hip joint, which can suffer fractures and dislocations. A 'knee slider' is used to measure

forces transmitted through the dummy's knees, particularly if they strike the lower fascia.

Lower Leg

Instruments fitted inside the dummies' legs measure bending, shear, compression

and tension, allowing injury risks to the tibia (shin-bone) and fibula (connecting knee to

ankle) to be assessed.

Feet and Ankles

Assessment of injury risk in the rental impact is made by afterwards measuring

distortion and rearward movement of the driver’s foot well area.

Fig: Euro SID II Fig: Hybrid III



INSTRUMENTATION

The dummies contain following three types of instrumentation: -

1. Accelerometers: - Measure the acceleration in a particular direction. This data

can be used to determine the probability of injury. Inside the dummy's head, there is an

accelerometer that measures the acceleration in all three directions (fore-aft, up-down, left-

right). There are also accelerometers in the other parts of the body.

2. Load Sensors: - Inside the dummy are load sensors that measure the amount of

force on different body parts during a crash. The maximum load in the bone can be used to

determine the probability of it breaking.

3. Movement Sensors: - These sensors are used in the dummy's chest. They

measure how much the chest deflects during a crash.

Before the crash-test dummies are placed in the vehicle, researchers apply different

colors of paint to the parts of the dummies' bodies most likely to hit during a crash. The

paint marks in the car will indicate what part of the body hit what part of the vehicle inside

the cabin. This information helps researchers develop improvements to prevent that type

of injury in future crashes.



ABSORPTION MECHANISM OF CRASH ENERGY

Obviously the ideal crash would be no crash at all. But, let's assume you are going

to crash, and that you want the best possible chances of survival. How can all of the safety

systems come together to give you the smoothest crash possible?

Surviving a crash is all about kinetic energy. When the body of occupant is moving

(say at 35 mph), it has a certain amount of kinetic energy. After the crash, when it comes

to a complete stop, it will have zero kinetic energy. To minimize risk of injury, removing

the kinetic energy as slowly and evenly as possible is done by some of the following

safety systems in the car: -

1. As soon as car hits the barrier the seatbelt can then absorb some of your energy before

the airbag deploys.

2. Milliseconds later as the driver moves forward towards the airbag, the force in the

seatbelt holding him back would start to hurt him, so the force limiters make sure that

the force in the seatbelts doesn't get too high.

3. Next, the airbag deploys and absorbs some more of your forward motion while

protecting you from hitting anything hard.

In a crash it is desirable that most of the crash energy is absorbed and dissipated in

the deformation of components of each vehicle. For this purpose: -

Crumple Zones are vacant spaces in the front portion of the car that act as cushions,

where metal parts are supposed to deform and absorb all the kinetic energy of the

vehicle.

The engine on most cars is mounted so that in a crash, it is forced backwards and

downward so that it won't come into the cabin and injure the occupant.

Increasing the use of engine/suspension cradles allows designers to better control this

deformation and to by-pass very rigid components such as engine blocks, which are

not effective energy absorbers.

To avoid load concentrations it is important that the crash forces are spread across the

face of the deformable barrier.



In a collision between two vehicles the occupants of the heavier vehicle would

generally be better off, due to the physics of the collision. In the case of four-wheel-

drive vehicles colliding with passenger cars, however, this advantage can be

diminished by a stiff front structure.

Integrity of the passenger compartment should be maintained in the crash test. The

steering column, dash, roof, roof pillars, pedals and floor panels should not be pushed

excessively inwards, where they are more likely to injure the occupants.



TYPES OF CRASH TESTS

Simulating every accident type is impossible, which is why there are number of

standardized crash tests (which may resemble most of the crashes that may take place)

based on international classifications and industry practices are used in the development of

the vehicle. This defines a repeatable way of conducting crashes, so that improvements

can be quantified and modifications made. The four standard crash tests conducted are:

Frontal Crash Test

Offset Crash Testing

Side Impact Test

Pole Crash Test

Frontal Crash Testing :

At 35 mph (56 kph), the car runs straight into a solid concrete barrier. This is

equivalent to a car moving at 35 mph hitting another car of comparable weight moving at

35 mph. The kinetic energy involved in the frontal crash test depends on the speed and

weight of the test vehicle. Crashing the full width of a vehicle into a rigid barrier

maximizes energy absorption so that the integrity of the occupant compartment, or safety

cage, can be maintained well in all but not in very high-speed crashes. Full-width rigid-

barrier tests produce high occupant compartment decelerations, so they're especially

demanding of restraint systems (Figure.1)



Frontal Offset Crash Testing:

Fig.1

Fig. 2

In offset tests, only one side of a vehicle's front end, not the full width, hits the

barrier so that a smaller area of the structure, about 40% of the width of the front of the

vehicle on the driver's side must manage the crash energy. This means the front end on the

struck side crushes more than in a full-width test, and intrusion into the occupant

compartment is more likely.

In the offset crash test the vehicle is travels at 64kph (40mph) and

collides with a crushable aluminum barrier, which makes the forces in the test

similar to those involved in a frontal offset crash between two vehicles of the

same weight. The resulting crash forces place severe demands on the structure of

the vehicle, particularly on the driver's side. This test is also conducted by using

two vehicles of same weight, at 40mph. (Figure: 2)

The test results can be compared only among vehicles of similar weight.

The vehicle structure affects the outcome of an offset frontal crash in two main

ways: -absorption and dissipation of crash energy and integrity of the passenger

compartment. The bottom line is that full-width tests are especially demanding

of restraints but less demanding of structure, while the reverse is true in offsets.



S ide Crash Test:

Fig.3

Fig.4

In the side test a sled (of about 1,368-kg) with a deformable "bumper" runs into the

side of the test vehicle at around 31mph. The test simulates a car that is crossing an

intersection being sides wiped by a car running a red light. Side impacts can be of two

types: - perpendicular impact and angled impact (as shown in figure above).

The protection of occupants in side impacts is more important as the space between the

car’s body and the occupant is much less than with the front and rear. Side impact crash

test ratings can be compared across vehicle type and weight categories, while frontal crash

test ratings cannot. This is because the kinetic energy involved in the side impact test

depends on the weight and speed of the moving barrier, which are the same in every test.

(Figure 3)



Pole Crash Test:

A series of tests are carried out to replicate accidents involving child and adult

pedestrians where impacts occur at 40kph (25mph). Impact sites are then assessed and

rated fair, weak and poor. As with other tests, these are based on European Enhanced

Vehicle-safety Committee guidelines Accident patterns vary from country to country

within Europe, but approximately a quarter of all serious-to-fatal injuries happen in side

impact collisions. Many of these injuries occur when one car runs into the side of another.

To encourage

manufacturers to

fit head protection

devices, an

optional pole or

head protection

test may be

performed, where

such safety

features are fitted.

Side impact head

airbags help to

protect the head by

providing a

padding effect and by preventing the head from passing through the window opening. In

the test, the car tested is propelled sideways at 29kph (18mph) into a rigid pole. The pole

is relatively narrow, so there is major penetration into the side of the car.

In an impact without the head protecting airbag, a driver's head could hit the pole with

sufficient force to cause a fatal head injury. Typically a head injury criterion of 5000 is

possible, five times that which indicates the likelihood of serious brain injury.

In contrast, the head injury criterion in these new crash tests with a head protection

airbag is around 100 to 300, well below the injury reference value. A side impact airbag

with head protection makes this kind of crash survivable despite the severity



SAFETY FEATURES

1. Anti-lock Brake Systems

Prevent a car's wheels from locking during 'panic' braking and allow the driver to

maintain steering control as the car slows down. It keeps the car going straight, even after

applying brakes on a slippery surface.

2. Side Impact Bars/Side Door beams

Side impact bars are made from high strength steel tubes and are fitted into the

central portion of the door panels, thus increasing their strength. Stronger doors protect

passengers during a side impact.

3. Three - Stage Protective Bumper

It includes

Unique plastic energy absorber and reinforced steel Impact.

Energy absorber that crushes upon collision that prevents severe damage

to body.

Reinforced Impact Beam and Bracket that perform a double shock

absorbing function.

4. Roll Control

A Roll Control device in the front suspension imparts greater stability and prevents

the car from toppling over while negotiating sharp curves at high speeds.

5. Fuel Tank safety

In some cars the fuel tank is designed to stay intact even in a big accident allowing

no leaks at all. The fuel tank is also centrally located for safety and performance-keeping it

out of way in the event of an accident.



6. Seat Belts

They hold the person in an optimal position in the event of a car crash. They also

reduce the risk of collision with the steering wheel, dashboard or windshield.

7. Air Bags

Airbags are very useful in avoiding two types of accidents: rear-end and head-on

collisions. They are very important in a crash because depending on the speed at impact

and the stiffness of the object struck, front air bags inflate to prevent your head and face

from striking your car's interior, especially the dashboard, steering wheel and windshield.

In a head-on crash, sensors take less than 1/20th of a second to alert the inflators that fill

the bag. Using air bags in conjunction with automatic safety belts provides much more

protection than using either one alone. Side air bags reduce the risk of occupants hitting

the door or object that crash through it. They provide additional chest protection by

inflating instantly during many side crashes; some, also provide head protection.

8. Head Restraints

Head restraints are extensions of the car's seats that limit head movement during a

rear-impact crash, thus, reducing the probability of neck injury.

9. Collapsible Steering

The steering wheel column in a collapsible steering works in two stages to absorb

impact in the event of an air crash. This protects the driver from being trapped between the

steering wheel and seat, during a collision.

10. Non-jamming Doors

During a heavy collision the front doors are pushed over the outer skin of the rear

doors, leaving them free to open.



CASE STUDY: CRASH TEST CONDUCTED ON A

“HONDA CR-V” BY INSURANCE INSTITUTE FOR

HIGHWAY SAFETY (IIHS)

The Honda CR-V is a compact SUV, manufactured since 1995 by Honda. It was

loosely derived from the Honda Civic. The "CR-V" stands for “Compact Recreational

Vehicle". It is produced in both four-wheel drive and front-wheel drive, with availability

differing by market.

TESTED VEHICLE SPECIFICATIONS:

2013 Honda CR-V EX 4wd

Class: Small SUV

Weight: 3,512 lbs.

Wheelbase: 103 in.

Length: 178 in.

Width: 72 in.

Engine: 2.4 L 4-cylinder

Side airbags: front and rear head curtain airbags and front seat-mounted torso airbags

Rollover sensor: designed to deploy the side curtain airbags in the event of an

impending rollover

Electronic stability control

Antilock brakes

Daytime running lights



IIHS FRONTAL CRASH TEST

TEST DETAILS:

Restraints/dummy kinematics — Dummy movement was well controlled.

The driver side curtain and side torso airbags deployed during the crash.

After the dummy moved forward into the frontal airbag, it rebounded into the seat

without its head coming close to any stiff structure that could cause injury.

Injury measures — Measures taken from the dummy indicate a low risk of any

significant injuries in a crash of this severity.

OVERALL EVALUATION:

Structure/safety cage

Injury measures

Restraints/dummy kinematicsHead/neck Chest Leg/foot, left Leg/foot, right

Good Acceptable Marginal Poor

IIHS FRONTAL OFFFSET CRASH TEST

TEST DETAILS:

Driver — the dummy’s head was protected from being hit by any hard structures,

including the intruding barrier, by a side curtain airbag that deployed from the roof

and a side airbag that deployed from the seat.

The frontal airbag also deploys during the test.

OVERALL EVALUATION:



Structure/safety cage

Injury measures

Restraints/dummy kinematicsHead/neck Chest Leg/foot, left Leg/foot, right


IIHS SIDE CRASH TEST

TEST DETAILS:

Driver — Measures taken from the dummy indicate that a fracture of the pelvis

would be possible in a crash of this severity. The risk of significant injuries to

other body regions is low.

Rear passenger — Measures taken from the dummy indicate a low risk of any

significant injuries in a crash of this severity.

OVERALL EVALUATION:

Injury measures

Head protection Structure/safety cageHead/neck Torso Pelvis/leg

Driver

Rear passenger




CRASH TEST RATINGS FOR THE CARS BY NHTSA

(NATIONAL HIGHWAY AND TRANSPORT SAFETY

AUTHORITY)

In frontal crashes, the worst score on the following three criteria determines the star

rating: -

Head Injury Criteria (HIC)

Chest deceleration

Femur load

In side-impact crashes, there are three criteria:

Driver and passenger injury measures

Head protection

Structural performance


Ratings for Frontal-Impact Tests

# Of Stars Result

5 10% or lower chance of serious injury

4 11% to 20% chance of serious injury



1 46% or greater chance of serious injury


Tata Indigo has passed all the standards of full frontal and offset frontal crash tests as

well as endurance safety tests. Tata has also recently tested Indica, Sierra and Safari

successfully.

Ford's Freestyle, a midsize SUV introduced for the 2012 model year, earned the highest

rating in a 40 mph frontal test.

NHTSA ratings for the 2013 Honda CR-V EX 4wd

Other, Overall Rollover Rating:…………………………………..

Side - Pole, Side - Pole:……………………………………………

Side, Rear Seat:……………………………………………………

Overall, Overall: ………………………………………………….

Side - Pole Barrier combined,

Side - Pole Barrier combined (REAR):……………………………

Front, Overall Front:………………………………………………

Side - Pole Barrier combined,


Ratings for Side-Impact Tests

# Of Stars Result

5 5% or lower chance of serious injury




1 26% or greater chance of serious injury


Side - Pole Barrier combined (FRONT):………………………….

Front, Driver's: …………………………………………………..

Side, Front Seat:.…………………………………………………

Side - Barrier, Side - Barrier: ……………………………………

Front, Passenger's:………………………………………………..

Side, Overall Side:……………………………………………….



CRASH TESTING C ENTERS

Throughout the world there are many institutes who crash test vehicles, each

organization’s test results are generally for vehicles sold in its respective country or

region.

Insurance Institute for Highway Safety (IIHS- U.S)

http://www.hwysafety.org/vehicle_ratings/ratings.htm

NHTSA (National Highway and Transport Safety Authority New Car Assessment

Programme USA) provides individual ratings for frontal impact, side impact and

roll-over resistance out of five-stars.

Euro NCAP: Established in 1997 and now backed by five European Governments.

www.euroncap.com

New Car Assessment Japan: evaluates the safety of automobiles currently on the

Japanese market.

http://www.nasva.go.jp/english

Australian NCAP (ANCAP): Australian and New Zealand automobile clubs

supports Australian New Car Assessment Program (ANCAP).

http://www.aaa.asn.au/ancap.htm

India has centers for crash testing at the Automotive Research Association of India

(ARAI) and Society of Indian Automobile Manufacturers (SIAM) in Bangalore.

Tata Motors’s is the only carmaker in India that has a crash-test facility located at

huge plant in Pune established in 1996.

CONCLUSION



The safety deficits of cars observed in accident statistics can be alleviated if the

structures of these cars are designed and optimized for the situation they will most likely

encounter in a real world situation.

One of the prime reasons for the alarming increase in deaths due to accidents in

India is that crash testing of vehicles is not mandatory. Every carmaker emphasizes that

his make is better. But the consumer has to change his approach and consider that car,

which can best avoid injuries to him in a crash. This will force the carmakers to crash test

all the vehicles they launch and provide all the necessary information to the consumer,

and facilitate him in buying a safe car.

Crash testing leads to improvement of the safety systems. These systems again

have to be tested for their workability during a crash. Hence crash testing plays a vital role

in continuous improvement of the safety systems. Design changes in vehicles like the

crumple zones and the location of engine block have been the results of evolution of crash

testing. Therefore in future, crash testing could suggest many more design changes, which

could further minimize the probability of injury during a crash. These observations stress

that any car make would not be complete without crash testing. Thus crash testing can be

a major factor that will make driving a more secure and reliable experience.

BIBLIOGRAPHY



Paper on Offset crash tests – Observations about vehicle design and structural

performance- by Michael Paine; Vehicle Design and Research Pty Limited;

Donald McGrane Crash lab, NSW Roads and Traffic Authority; Jack Haley

NRMA Limited.

http://www.tata.com/tata_motors/articles/index.htm

http://www.nhtsa.dot.gov/cars/testing/ncap/

www.howstuffworks.com

www.aj.com

http://www.iihs.org/ratings/rating.aspx?id=586

http://www.driveandstayalive.com/info%20section/crash%20testing/aaa-

index_crash-testing-index-and-intro.htm

http://www.cars.com/honda/cr-v/2013/safety-ratings/


crash testing of cars

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