Crash tests are performed to ensure vehicle safety standards. There are several types of collision tests including frontal impact tests where the vehicle impacts a wall, moderate and small overlap tests where only part of the vehicle impacts an object, and side impact tests. Noise, vibration, and harshness tests evaluate vehicle noise and vibration both objectively and subjectively. Rollover tests examine vehicle stability in the event of a rollover crash. Wind tunnel tests study vehicle aerodynamics and were initially developed for aircraft but are now widely used for automotive research using both models and full-scale vehicles.

1. • Topic :
1. Collision Test :
A crash test is a form of destructive testing usually performed in
order to ensure safe design standards in crashworthiness and crash
compatibility for various modes of transportation (see automobile
safety) or related systems and components.
Crash testing helps develop safety systems and inform consumers,
which takes some of that risk away. While smashing cars into walls or
each other may seem wasteful, the data these tests yield is invaluable.

2. • Types of collision Test :
1. Frontal-impact test :
Vehicles usually impact a solid concrete wall at
a specified speed, but these can also be vehicle impacting vehicle tests.
2. Moderate Overlap tests :
In which only part of the front of the car
impacts with a barrier (vehicle). These Are important, as impact
forces(approximately) remain the same as with a frontal impact test, but
a smaller Fraction of the car is required to absorb all of the force

3. 3. Small Overlap tests :
This is where only a small portion of the car’s
structure strikes an object such as a pole Or a tree, or if a car were to
clip another car.

4. 4. Side-impact :
These forms of accidents have a very significant
likelihood of fatality, as cars do not Have a significant crumple zone to
absorb the impact forces before an occupant is injured.

5. 1. NVH Test :
Noise, vibration, and harshness (NVH), also known as noise
and vibration (N&V), is the study and Modification of the noise and vibration
characteristics of vehicles, particularly cars and trucks. While noise and
Vibration can be readily measured, harshness is a subjective quality, and is
measured either via “jury” evaluations, Or with analytical tools that can
provide results reflecting human subjective impressions.
In some cases the NVH engineer is asked to change the sound quality, by
adding or subtracting particular Harmonics, rather than making the vehicle
quieter.

6. • Tools/Instruments :
Typical instrumentation used to measure NVH
include microphones, accelerometers and force gauges, or load Cells.
Many NVH facilities will have semi-anechoic chambers, and rolling
road dynamometers. Typically signals Are recorded direct to hard disk
via an analogy-to-digital converter.
In the past magnetic or DAT tape recorders Were used. The integrity of
the signal chain is very important, typically each of the instruments used
are fully Calibrated in a lab once per year, and any given setup is
calibrated as a whole once per day.

7. NVH Test picture

8. 3.Roll Over Test :
A rollover is a type of vehicle crash in which a vehicle
tips over onto its side or roof. Rollovers have a Higher fatality rate than
other types of vehicle collisions.
Vehicle rollovers are divided into two categories: tripped and
unstripped. Tripped rollovers are caused by Forces from an external
object, such as a curb or a collision with another vehicle. Unstripped
crashes are the result Of steering input, speed, and friction with the
ground.

9. • The most common type of tripped rollover occurs
when a vehicle is sliding sideways, and the tires
strike A curb, dig into soft ground, or a similar event
occurs that results in a sudden increase in lateral
force. The physics Are similar to cornering
rollovers. In a 2003 report, this was the most
common mechanism, accounting for 71% Of single-
vehicle rollovers.

10. 4.Wind Tunnel Test :
For those of you that don’t already know this, wind
tunnel testing were initially aimed at conducting Aerodynamic research
mostly involving aircrafts. The first enclosed wind tunnel for
aeronautical purposes was Designed and operated in 1871 by Francis
Herbert Wenham from the Aeronautical Society of Great Britain,
Delivering many fundamental discoveries. However, wind tunnel testing
was only applied to automobiles almost One century later, after years of
using computer simulations instead of real-life procedures.

11. • Types of wind tunnel Testing :
1. Model Scale Testing : Depending on the size of the vehicle and the
limitations of the test facility models typically lie between 30% - 60%.
Model scale testing is ideal for rapid evaluation of the influence of
different body styles and features on the vehicle’s aerodynamics.

12. 2. The First : It wasn’t until 1960 that the first dedicated automotive
wind tunnel was inaugurated by the specialists at MIRA, opening its
doors for vehicle aerodynamics research. Since then, MIRA’s
aerodynamicists have been investigating the use of computers to
predict the aerodynamic performance of different vehicle shapes
initially with in-house developed empirically based codes.

13. 3.The Largest : Put into operation in 1980, the GM Aerodynamic
Laboratory is the largest wind tunnel in the world dedicated to
automotive use (the only bigger tunnels are used by the aerospace
industry). This wind tunnel features a 4,500 hp fan that can create
winds up to 138 miles per hour.