Wednesday 30 March 2011

Even dummies wear seat belt

video about crash test dummies that control the world and use human as a crash subject. this video to show us that even a crash test dummies wear a seat belt. fasten ur seat belt and enjoy this video..

Friday 25 March 2011

Roof Strength Evaluations

Rollover evaluations

Small cars

To measure roof strength, a metal plate is pushed against one corner of a vehicle's roof at a constant speed. The maximum force sustained by the roof before 5 inches of crush is compared to the vehicle's weight to find the strength-to-weight ratio. This is a good assessment of vehicle structural protection in rollover crashes.

Each model is rated based on our measured curb weight of a vehicle with typical engine, transmission, and equipment options. However, when the same model is available in a configuration over 10% heavier than the typically equipped vehicle, a separate rating is assigned.


Good Good   Acceptable Acceptable   Marginal Marginal   Poor Poor   |   Vehicles are listed in order of performance

Model Overall rating Curb weight (lb) Peak force (lb) Strength-to-weight ratio
Nissan Cube
2009-11 models
Good 2,833 20,569 7.26 









Scion xB
2008-11 models
Good 3,078 21,041 6.84
Scion tC
2011 models
Good 3,123 17,738 5.68
Mazda 3 sedan
2011 models mfg. after Dec. 2010
Good 2,922 15,541 5.32
Volkswagen Golf
2010-11 models
Volkswagen Rabbit
2006-09 models
Volkswagen GTI
2010-11 models
Good 3,042 15,970 5.25
Toyota Corolla
2009-11 models
Good 2,749 14,006 5.09
Mazda 3 hatchback
2011 models mfg. after Dec. 2010
Good 3,023 15,380 5.09
Chevrolet Cruze
2011 models
Good 3,143 15,944 5.07
Mini Cooper Countryman
2011 models
Good 2,984 14,829 4.97
Subaru Impreza wagon
2008-11 models
Good 3,132 14,485 4.62
Kia Forte
2010-11 models mfg. after Oct. 2009
Good 2,859 13,084 4.58
Subaru Impreza sedan
2008-11 models
Good 3,125 14,069 4.50
Honda Civic 4-door
2006-11 models
Good 2,760 12,532 4.48
Kia Soul
2010-11 models
Good 2,886 12,489 4.33
Mitsubishi Lancer
2008-11 models
Good 2,984 12,863 4.31
Rating does not apply to 4-wheel drive models. Rating of these models is Acceptable.
Honda Insight
2010-11 models
Acceptable 2,700 8,970 3.32

Sunday 20 March 2011

Side impact crash testing/ratings criteria

Today's passenger vehicles are more crashworthy than they used to be, especially in frontal crashes. As occupant protection in frontal crashes improves, the relative importance of protection in side impacts increases. From the early 1980s until 2000, driver death rates per million cars registered decreased 47 percent. Most of this improvement was in frontal crashes, in which driver death rates decreased 52 percent. In contrast, the decrease in side impacts was only 24 percent.


In crashes with another passenger vehicle, 51 percent of driver deaths in recent model cars during 2000-01 occurred in side impacts, up from 31 percent in 1980-81. During the same time, the proportion of deaths in frontal impacts declined from 61 percent to 43 percent.

These changes are attributable to two effects. There have been significant improvements in frontal crash protection — standard airbags, improved structural designs, and higher belt use rates, for example. At the same time, growing sales of SUVs and pickups have exacerbated height mismatches among passenger vehicles, thereby increasing the risks to occupants of many vehicles struck in the side. In crashes between cars and other passenger vehicles during 2000-01, almost 60 percent of the driver deaths in the cars struck on the driver side were hit by SUVs or pickups — up from about 30 percent during 1980-81.

Since 1997 the federal New Car Assessment Program, which compares crashworthiness among new passenger vehicles, has included side impacts. In these tests, an impactor with a deformable front end representing the front of a car is used to strike the sides of the vehicles being assessed. This moving deformable barrier was developed in the early 1980s, when cars represented most of the vehicles on the road. The height of the barrier's front end is below the heads of the dummies that measure injury risks in the side-struck vehicles. These federal tests don't assess the risks of head injury from impacts with vehicles like SUVs and pickups.

The changed vehicle mix and high risks to occupants of side-struck vehicles when the striking vehicles are SUVs or pickups led the Institute to modify the moving deformable barrier used in the federal test so the front end represents the geometry of a typical SUV or pickup. The result is a barrier that's higher off the ground, taller, and contoured.

Before initiating this side impact crashworthiness evaluation program in 2003, the Institute conducted extensive developmental tests. These included tests comparing the results from side impacts with barriers versus side impacts with SUVs or pickups.

The test configuration resulting from this research is a 31 mph (50 km/h) perpendicular impact into the driver side of a passenger vehicle. The moving deformable barrier that strikes the test vehicle weighs 3,300 pounds (1,500 kg) and has a front end shaped to simulate the typical front end of a pickup or SUV. In each side-struck vehicle are two instrumented SID-IIs dummies representing a small (5th percentile) female or a 12-year-old adolescent. These dummies are positioned in the driver seat and the rear seat behind the driver.

This is the first US consumer information test program to use a dummy that represents small females. There are two reasons for this choice. One is that data from serious real-world side impacts indicate that women are more likely than men to suffer serious head injuries. The other reason is that the head of the smaller SID-IIs driver dummy is in the window area where people's heads are more vulnerable to being struck by the front end of a striking vehicle in a real-world side impact.

The Institute's side impact test is severe. Given the designs of today's vehicles, it's unlikely that people in real-world crashes as severe as this test would emerge uninjured. But with good side impact protection, people should be able to survive crashes of this severity without serious injuries.

NOTE: 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. In contrast, the kinetic energy involved in the frontal crash test depends on the speed and weight of the test vehicle.


Ratings criteria

Overall evaluation (side):
The three factors evaluated in the Institute's side impact test — driver and passenger injury measures, head protection, and structural performance — determine each vehicle's overall side crashworthiness evaluation. The order in which vehicles are listed depends on performance in frontal offset crash tests as well as side impact tests. Ideally vehicles should be good performers in both test configurations — a double good. Head restraint and bumper evaluations influence the rankings of vehicles with otherwise similar overall crashworthiness performance.

Guidelines for rating injury measures

Injury measures:
Obtained from two SID-IIs dummies, one in the driver seat and the other in the rear seat behind the driver, injury measures are used to determine the likelihood that a driver and/or passenger would have sustained significant injury to various body regions. Measures are recorded from the head, neck, chest, abdomen, pelvis, and femur. These injury measures, especially from the head/neck and torso (chest and abdomen), are major components of each vehicle's overall evaluation.

Head protection:
To supplement head injury measures, the movements and contacts of the dummies' heads during the crash are evaluated. This assessment is more important for seating positions without head protection airbags, which (assuming they perform as intended) should prevent injurious head contacts. Very high head injury measures typically are recorded when the moving deformable barrier hits the dummy's head during impact. However, a "near miss" or a grazing contact also indicates a potential risk of serious injury in a real-world crash. This is because small differences in occupants' heights or in their seating positions compared with the test dummies could result in a hard contact and high risk of serious head injury. In the rear seat, the potential for serious injury is influenced by whether the seating position puts occupants' heads in proximity to areas designed with padding or something else to reduce impact forces versus areas with hard or unprotected structures. Analysis of the movement and contact points of the dummies' heads during the side impact crash test is used to assess this aspect of protection.

Structure/safety cage:
Structural performance is based on measurements indicating the amount of intrusion into the occupant compartment around the B-pillar (between the doors). This assessment indicates how well a vehicles side structure resisted intrusion into the driver and rear-seat passenger space. Some intrusion into the occupant compartment is inevitable in serious side impacts. Any intrusion that does occur should be uniform both horizontally and vertically and shouldn't seriously compromise the driver and passenger space. Less intrusion helps assure that other occupants of sizes and in seating positions different from the dummies also would have lower injury risk.

Test verification

Verification ratings are based on 31 mph side crash tests conducted by manufacturers for vehicles meeting requirements established by the Institute. Manufacturers supply information on basic vehicle and test parameters, measurements of B-pillar intrusion into the occupant compartment, injury data recorded on dummies representing small females in the driver and rear passenger seats, and video of the tests. Institute engineers review this information and rate vehicles based on the same evaluation parameters used for the Institute's side test. To ensure manufacturers' good faith participation, the Institute conducts audit tests.

Only redesigned vehicles with immediate predecessors that earned the top rating of good in previous Institute tests are eligible for verification ratings. Substantially redesigned vehicles with significant changes in size, weight, or body style aren't eligible. The Institute will continue to test these vehicles.

Verification assures that automakers still pay attention to side crash protection as they redesign their vehicles and introduce new ones. This approach is possible because of manufacturers' actions since we introduced the side crash test program. They have incorporated side crash test performance plus government-required and other consumer information crash testing into their guidelines. They routinely conduct their own side tests during the design process. In recognition of this, the verification approach goes a step beyond an Institute policy in place since the beginning of the side test program. Manufacturers always have been asked to confirm whether the Institute's ratings could be carried over from one model year to the next. Based on this information, the Institute has been carrying over ratings for vehicles with no significant design changes.

When the Institute began evaluating side crashworthiness by vehicle group beginning in 2003, only about 1 of 5 vehicles tested earned good ratings. Nearly all of the others were rated poor. Since then, the Institute’s side tests have prompted huge improvements in occupant protection in side impacts. Manufacturers have responded to this testing program by changing the designs of their vehicles to improve side crashworthiness and equipping their vehicles with side airbags. Now most current passenger vehicle designs with side airbags earn good ratings based on Institute tests.

The Institute's test primarily assesses how well a vehicle's side structure prevents intrusion into the occupant compartment, or safety cage and, for vehicles with side airbags, how well the head, torso, and pelvis are protected by the airbags. If the occupant space remains largely intact, then the side impact restraint systems can control the motion of the crash test dummy and help keep injury measures low. But if there's significant deformation of the safety cage and intrusion into the compartment, then the restraint systems are less likely to keep the measures low. Newer vehicles have much stronger occupant compartments, in large part because of the steps automakers have taken to earn good ratings in the Institute's side crash tests, and side airbags have become standard equipment in most passenger vehicles since these tests began. Side crash test verification will ensure these gains are maintained.

Monday 14 March 2011

Procedures for rating roof strength(3)

More than 10,000 people a year are killed in rollovers. The best way to prevent the deaths is to keep vehicles from rolling over in the first place. Electronic stability control is significantly reducing rollovers, especially fatal single-vehicle ones. When vehicles do roll, side curtain airbags help protect the people inside, and belt use is essential. However, for these safety technologies to be most effective, the roof must be able to maintain the occupant survival space when it hits the ground during a rollover. Stronger roofs crush less, reducing the risk that people will be injured by contact with the roof itself. Stronger roofs also can prevent occupants, especially those who aren't using safety belts, from being ejected through windows, windshields, or doors that have broken or opened because the roof has deformed.
In the Institute's roof strength test, a metal plate is pushed against 1 side of a roof at a constant speed. To earn a good rating, the roof must withstand a force of 4 times the vehicle's weight before reaching 5 inches of crush. This is called a strength-to-weight ratio. For an acceptable rating, the minimum required strength-to-weight ratio is 3.25. A marginal rating value is 2.5. Anything lower than that is poor.
The Institute's test method is the same one that has been used for testing under the federal roof strength regulation since 1973, but with much higher requirements. Vehicles only need a strength-to-weight ratio of 1.5 to meet the federal regulation. While the actual roof strengths of vehicles may surpass this minimum level by a large amount, this information has not been available to consumers. Institute research has found that a vehicle with a roof strength-to-weight ratio of 4.0 has an estimated 50 percent reduction in the risk of serious and fatal injury in single-vehicle rollover crashes compared with the minimum level of 1.5.
Video roof strength test

Sample data comparing test result for vehicles rated good and poor

Monday 7 March 2011

Frontal offset crash test details Ratings criteria Crash test verification(2)

Nowday's passenger vehicles are designed to be more safety than they used to be. Still, about 10,000 passenger vehicle occupants die in crashes on Malaysian roads each year. About half of the deaths occur in frontal crashes.

Since 1970s, the federal New Car Assessment Program has compared frontal crashworthiness among new passenger vehicles. This program, which involves 40 mph crash tests into a full-width rigid barrier, has been highly successful in providing consumers with comparative crashworthiness information. It also has been a major contributor to the crashworthiness improvements that characterize recent passenger vehicle models. 
Full-width and offset tests complement each other. For Frontal Crash Test, 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 very high-speed crashes. Full-width rigid-barrier tests produce high occupant compartment decelerations, so they're especially demanding of restraint systems. 

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 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. 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.
 Video Overhead view of frontal offset test

The Institute began frontal offset crash testing in 1995. In the Institute's 40 mph offset test, 40 percent of the total width of each vehicle strikes a barrier on the driver side. The barrier's deformable face is made of aluminum honeycomb, which makes the forces in the test similar to those involved in a frontal offset crash between two vehicles of the same weight, each going just less than 40 mph. Test results can be compared only among vehicles of similar weight. Like full-width crash test results, the results of offset tests cannot be used to compare vehicle performance across weight classes. This is because the kinetic energy involved in the frontal test depends on the speed and weight of the test vehicle, and the crash is more severe for heavier vehicles. Given equivalent frontal ratings for heavier and lighter vehicles, the heavier vehicle typically will offer better protection in real-world crashes.


Rating Criteria
Overall evaluation (frontal): The three factors evaluated in the frontal offset crash test 
— structural performance, injury measures, and restraints/dummy kinematics
— determine each vehicle's overall frontal offset crashworthiness evaluation. The order in which vehicles are listed depends on performance in side impact tests as well as frontal offset crash tests. Ideally vehicles should be good performers in both test configurations 
— a double good. Head restraint and bumper evaluations influence the rankings of vehicles with otherwise similar overall crashworthiness performance.
  
Structure/safety cage: Structural performance is based on measurements indicating the amount and pattern of intrusion into the occupant compartment during the offset test. This assessment indicates how well the front-end crush zone managed the crash energy and how well the safety cage limited intrusion into the driver space. Intrusion is measured at 9 places in the driver seating area by comparing the precrash and postcrash positions of these 9 points. (The steering wheel intrusion is split into upward and rearward components to obtain a total of 10 measurements.) Larger intrusion numbers indicate more collapse of the safety cage. For more information about how these measurements are made and compared, 
 
and

Injury measures: Obtained from a 50th percentile male Hybrid III dummy in the driver seat, injury measures are used to determine the likelihood that a driver would have sustained injury to various body regions. The measures recorded from the head, neck, chest, legs, and feet of the dummy indicate the level of stress/strain on that part of the body. Thus, greater numbers mean bigger stresses/strains and a greater risk of injury. For more information about how these measurements are made and compared,
 and

Restraints/dummy kinematics (movement): Significant injury risk can result from undesirable dummy kinematics — for example, partial ejection from the occupant compartment — in the absence of high injury measures. This aspect of performance involves how safety belts, airbags, steering columns, head restraints, and other aspects of restraint systems interact to control dummy movement. For more information about how these measurements and judgments are made and compared,
Guidelines for rating restraints and dummy kinematics
Test verification
Verification ratings are based on 40 mph frontal offset crash tests conducted by manufacturers for vehicles meeting requirements established by the Institute. Manufacturers supply information on basic vehicle and test parameters, measurements of intrusion into the occupant compartment, injury data recorded on a dummy representing an average-size man in the driver seat, and video of the tests. Institute engineers review this information and rate vehicles based on the same evaluation parameters used for the Institute's frontal offset test. To ensure manufacturers' good faith participation, the Institute is conducting audit tests.

from my point of view this Frontal offset crash tests conducted by the Institute since 1995 have prompted huge improvements in how vehicles protect people in frontal crashes.Then manufacturers responded by changing the designs of their vehicles to improve frontal crashworthiness. The result has been a turnaround in the frontal ratings. Now virtually every current passenger vehicle design the Institute has evaluated earns good ratings.

Tuesday 22 February 2011

Vehicle Crash Tests (1).

A crash test is a type of damaging test procedure that is performed on  motor vehicles to make sure they meet the required safety standards and  demonstrate the effects on the vehicle and occupants in potential crash  incidences. Crash testing includes frontal-impact, offset, rollover, side-impact, roadside hardware, and old against new crash tests.

 
There are 6 types in crash tests:



  • Frontal Impact Test
 
Ford Falcon Frontal ANCAP Crash Test



  • Offset Test

Toyota Seinna Offset Frontal Crash Test


 

  • Side-Impact Test


  BMW Side-Impact Crash Test


  • Rollover Crash Test 

Volvo XC90 Rollover Crash Test


  • Road Side Hardware Crash Tests
Roadside hardware crash tests and used to make sure crash obstructions  and crash padding will protect the occupants of a vehicle from hazards  on the road.
These tests also make sure roadside equipment including signs,  guardrails, light poles do not create an excessive risk to vehicle  passengers.


 

  • Old Versus New
Old against new tests assess the impact of old and larger vehicles  versus new and smaller vehicles or two different styles of the same  model to display the improved crash effect of model advancements. 


Data

example of data in crash test

Crash tests are conducted under rigorous scientific and safety standard. Each crash test is very expensive so the maximum amount of data must be extracted from each test. Usually, this requires the use of high-speed data-acquisition, at least one triaxial accelerometer and a crash test dummy, but often includes more.