bumper is a structure attached or integrated with the front and rear end of a motor vehicle, to absorb collisions in small collisions, ideally minimizing repair costs. Invented by Briton Frederick Simms in 1901, the bumper ideally minimizes the height mismatch between the vehicle and protects the pedestrian from injury. Regulatory measures have been put in place to reduce vehicle repair costs, and have recently impacted pedestrians.
Video Bumper (car)
Construction
Bumper was originally just a rigid metal bar. The first bumper appeared in the vehicle in 1897, and was installed by Nesselsdorfer Wagenbau-Fabriksgesellschaft, a Czech carmaker. In fact, the bumper's construction is unreliable, and they fall out of the vehicle. This bumper only displays cosmetic functions. The first functional bumpers, designed to absorb impacts, emerged in 1901. Discovered and tested in England by Frederick Simms, and he obtained a patent for this invention in 1905. After that, several automakers tried to equip their vehicle with random bumpers however , the first widespread bumper application appeared in Model A by Ford in 1927. In 1968 the Pontiac GTO, General Motors gave birth to the colorful front bumper "Endura" designed to absorb low-speed impacts without permanent deformation.. It appeared in a television commercial where John DeLorean crashed into a new car with a hammer and there was no damage to it. Similar elastomer bumper is also available on the front and rear of the 1970-'71 Plymouth Barracuda, and in 1971, Renault introduced a plastic bumper (compound sheet printing) on ​​Renault 5.
The current design practice is for bumper structures in modern cars to consist of plastic coverings over reinforcing bars made of steel, aluminum, fiberglass composites, or plastics. The most modern car bumpers have been made from a combination of polycarbonate (PC) and Acrylonitrile butadiene styrene (ABS) called PC/ABS.
Maps Bumper (car)
Physics
Bumper offers protection against other vehicle components by removing the kinetic energy generated by the impact. This energy is a function of the mass of the vehicle and the velocity of the squared. Kinetic energy is equal to 1/2 mass and squared product of speed. In form of formula:
A bumper that protects vehicle components from damage at 5 miles per hour should be four times stronger than a protective bumper at 2.5 miles per hour, with concentrated energy dissipation concentrated in the extreme front and rear of the vehicle. A small increase in bumper protection can lead to weight gain and loss of fuel efficiency.
Until 1959, such stiffness was seen as beneficial to passenger safety among automotive engineers. The modern theory of vehicle accidents leads in the opposite direction, leading to progressively progressive vehicles. Truly rigid vehicles may have excellent bumper protection for vehicle components, but will offer poor passenger safety.
Pedestrian safety
Bumper is increasingly designed to reduce injury to pedestrians grabbed by cars, such as through the use of flexible bumper covers. The front bumper, in particular, has been lowered and made of a softer material, such as foam and plastic that can be destroyed, to reduce the hard impact of the foot.
High mismatch
For passenger cars, the height and placement of bumpers are legally determined under US and EU regulations. Bumpers do not protect against medium-speed collisions, because during emergency braking, the suspension changes the pitch of each vehicle, so bumpers can cut off each other when the vehicle collides. Preventing override and underride can be done with a very high bumper surface. Active suspension is another solution to maintain vehicle level.
The height of the seat from the road surface is very important in involving other protective systems. The airbag dispersal sensors usually do not trigger up contact with obstruction, and it is important that the front bumper be the first part of the vehicle to make contact in case of a frontal collision, to leave sufficient time to inflate the protective cushion.
The crush zone that absorbs energy is completely ineffective if they are physically passed; Extreme examples of this occur when the elevated platform of the tractor-trailer actually loses the front bumper of the passenger car, and the first contact is with a glass glazed from the passenger compartment.
Truck vs. car
Reduced collisions, where smaller vehicles such as passenger sedans glide under larger vehicles such as tractor-trailers often result in severe injuries or fatalities. The platform bed of a typical tractor-trailer is at the height of an adult's head sitting in a typical passenger car, and can cause severe head trauma even in medium-speed collisions. About 500 people die this way in the United States each year.
Following the death of actress Jayne Mansfield in 1967 in a car/truck accident, the US government agency NHTSA recommended the need for a rear guard, also known as "Mansfield bar", "ICC bar", or "DOT (Department of Transportation)) bumper". They should be no more than 22 inches (56 cm) from the road. The trucking industry is slow to improve this security feature, and there is no requirement to fix the damaged ICC blade in the service. However, in 1996, NHTSA increased the requirements for the prevention structure behind the truck trailer, and Transport Canada went further with more stringent requirements for buffer rear security buffers, and in July 2015 NHTSA issued a proposal to improve US performance requirements to bottom guard.
Many European countries also have needed side guards, to reduce deadly collisions where cars affect trucks from the side. Different types of side guards different from this nature are being used in Japan, US, and Canada. However, they are not needed in the United States.
SUV vs. car
A simple mismatch between the height of the SUV bumper and the side door protection of passenger cars has allowed serious injury at relatively low speeds. Unlike trucks, SUVs with bumper more than 22 inches (56 cm) from legal roads in the United States, such as vehicles with explosive fuel tanks located behind the rear axle (see Ford Pinto). In the United States, NHTSA is studying how to solve this problem in 2014.
Beyond lethal interactions, the cost of auto collision/passenger SUV repairs can also be significant due to height mismatch. This mismatch may cause the vehicle to become so damaged that it can not be operated after a low-speed crash.
Rule
In most jurisdictions, bumpers are legally required in all vehicles. Regulations for car bumper have been implemented for two reasons - to enable the car to maintain low-speed impact without damaging the vehicle's security system, and to protect pedestrians from injury. This requirement is contradictory: bumpers that withstand clashes well and minimize repair costs tend to injure more pedestrians, while pedestrian-friendly pedestrians tend to have higher repair costs.
Although vehicle bumper systems are designed to absorb low-speed collision energy and help protect the safety of cars and other expensive components located nearby, most bumpers are designed to meet only the minimum regulatory standards.
International standards
The international safety rules, originally designed as European standards under the auspices of the United Nations, have now been adopted by most countries outside North America. It determines that the car security system still has to function normally after the pendulum is straight or the barrier effect moves from 4 km/h (2.5 mph) to the front and rear, and to the front and rear corners of 2.5 km/h (1.6 mph ) at 45.5 cm (18 inches) above the ground with the vehicle loaded or lowered.
Pedestrian safety
European countries have implemented regulations to address 270,000 death problems annually in pedestrian/car accidents around the world.
Bull bar
Special bumpers, known as "bull bars" or "roo bars", protect vehicles in rural environments from collisions with large animals. However, studies have shown that the bar increases the threat of death and serious injury to pedestrians in urban environments, because the bulls are rigid and radiate all the forces of a collision into pedestrians, unlike the bumpers that absorb some of the strength and squeeze. In the European Union, sales of rigid metal bull bars that do not comply with the relevant pedestrian safety standards have been banned.
Bumper off-road
Off-road vehicles often use aftermarket off-road bumpers made of heavy metals to improve road clearance, maximize departure angle, clean larger tires and ensure additional protection from these elements. Just like the bull bars, the off-road bumper has a rigid construction and sends all the collision forces to the object it hit, which is more dangerous for pedestrians than the factory plastic bumper. The legality of the aftermarket off-road bumper varies significantly from one country to another (from state to state in the US).
United States
The United States focuses on protecting consumers from repair costs, using government law.
First standard 1971
In 1971, the US National Highway Traffic Safety Administration (NHTSA) issued the first state regulations applicable to passenger car bumpers. Federal Motor Vehicle Safety Standard No. 215 (FMVSS 215), "Exterior Protection," entered into force on September 1, 1972 - when most car manufacturers will begin producing their 1973 model vehicles. Standard prohibited functional damage to certain safety related components such as headlamps and fuel system components when the vehicle is subjected to a limiting collision test at 5 miles per hour (8 km/h) for front and 2.5 mph (4 km/h) for rear bumper system. The requirements effectively eliminate car bumper designs featuring integral automotive lighting components such as tail lights.
In October 1972, the US Congress enforced the Motor Vehicle Information and the Cost-Efficiency Act (MVICS), which required NHTSA to issue bumper standards that resulted in "cost reduction for public and consumers". Factors to consider include implementation costs and benefits, standard effects on insurance costs and legal costs, time savings and consumer discomfort, and health and safety considerations.
1973 model passenger cars sold in the US use a variety of designs. They range from non-dynamic versions with solid rubber protectors, to "recoverable" designs with telescoping shock absorbers of oil and nitrogen filled.
The standard was further tightened for a 1974 model passenger car, with high-front and rear bumper standards that could impact angles at 5-miles per hour (8 km/h) without damage to car lights, safety equipment, and engines. There is no provision in the law for consumers to 'opt-out' of this protection.
Regulatory effect on design
Cars for the US market are equipped with large, large, heavy, and protruding bumper to meet the standard 5-hour bumper applicable from 1973 to 1982. This often means the addition of the entire length of the vehicle, as well as the new front and rear designs to incorporate the bumper stronger energy absorber. Passenger cars feature flexible gap-concealing filler panels between bumper and car bodywork causing them to have a "big and concrete look". The notable exceptions of the year are the new Matador AMC coupe featuring a "free-standing" bumper with its own rubber foot protector to hide a retractable shock absorbers.
All 'domestic' cars have this feature, and imported vehicles must also be obeyed. With very few exceptions, such as Volvo 240 and Rolls-Royce Silver Shadow, foreign manufacturers only sell this feature in their mandated markets, US and Canada, so the 'break-from-world' model has a very different look.
The US bumper height requirement effectively makes some models, such as CitroÃÆ'¡n SM, suddenly ineligible to import into the United States. Unlike international safety rules, US regulations are written without provision for hydropneumatic suspension.
Standard of zero damage 1976
The requirements set out under MVICS were consolidated with the requirements of Federal Motor Vehicle Safety Standard Number 215 (FMVSS 215, "Vehicle Exterior Protection") and announced in March 1976. This new bumper standard is placed in the Federal Regulatory Rules of the United States at 49 CFR 581, Federal Motor Vehicle Safety Standard at 49CFR571. The new requirements, applicable to the 1979-model passenger car, are called "Phase I" standards. At the same time, the requirement of zero damage, "Phase II", was applied to the bumper system in 1980 and new cars. The most stringent requirements applied in the 1980 to 1982 model vehicles; 5 miles per hour (8 km/h) front and rear barrier tests and pendulum crashes are required, and no damage is allowed for outside bumper 3 / 8 inside (10 mm) dented and 3 / 4 inside (19 mm) displacement from the original position of the bumper.
All-wheel-drive "cross-over" cars like Eagle AMC are classified as multi-purpose vehicles or trucks, and are thus freed from standard passenger car bumpers.
Resilience was reduced in 1982
The newly elected Reagan administration has promised to use a cost-benefit analysis to reduce the regulatory burden on industries, which impact on this standard.
As discussed in detail under Physics , before 1959, the believer the stronger the structure, including the bumper, the safer the car. The analysis then leads to an understanding of the crumple zone, rather than rigid construction that proves lethal to passengers, because the power of the collision goes directly into the vehicle and onto the passenger.
NHTSA changed the bumper standard in May 1982, halving the front and rear impact test speeds for 1983 and new car bumpers from 5 miles per hour (8 km/h) to 2.5 miles per hour (4 km/h), and accidents at angle of test speed from 3 miles per hour (5 km/h) to 1.5 miles per hour (2 km/h). In addition, the Phase II requirement of zero damage is rolled back to the Phase I damage allowance. At the same time, the passenger car bumper height requirement of 16 to 20 inches (41-51 cm) is established for passenger cars.
NHTSA evaluated the results of its amendments in 1987, noting that it resulted in lower manufacturing costs and weight, offset by higher repair costs.
Despite these findings, consumers and insurance groups both denounced bumper standards that weakened. They presented the argument that the 1982 standard increased overall consumer costs with no allowances except to the automaker. In 1986, Consumer Union filed NHTSA to return to Phase II standards and disclose bumper power information to consumers. In 1990, NHTSA rejected the request.
Market failures are created when the consumer has no information to select an autos based on better/worse repair costs. In the United States, this gap is assisted by the Insurance Institute for Highway Safety, which diverts the vehicle to a low speed barrier test (6 mph or 9.7 km/h) and publishes repair costs. The successful car maker in this test will publish it.
For example, in 1990, the Insurance Institute for Highway Safety conducted four crash tests on three different instances of the Plymouth Horizon. The results illustrate the effect of changes to US bumper regulations (repair costs cited in 1990 US dollars):
- 1983 Horizon with 5-mph Phase-II bumper: $ 287
- 1983 Horizon with Phase-I 2.5-mph bumper: $ 918
- Horizon 1990: $ 1,476
Further reading (below) outlines Antonin Scalia's market advisor's view and Joan Claybrook's government intervention advocate on this rule.
Canada
The Canadian bumper standards, first imposed at the same time as the United States standard, are generally similar to US regulations of 8.5 km/h (5 mph). Canada reflects the US bill in the region, but does not revise it to 4 km/h (2.5 mph) based on the 1982 Cost Benefit Analysis.
Some automakers choose to provide stronger Canadian bumper specifications throughout the North American market, while others choose to provide weaker bumpers in the US market, another hurdle for importing private vehicles between the US and Canada.
In early 2009, Canadian regulations shifted to align with US Federal standards and international ECE regulations. As in the US, consumer protection groups are upset with the changes, while Canadian regulators state that a 4 km/h (2.5A mph) test speed is used worldwide and is more compatible with improved pedestrian protection in pedestrian-vehicle accidents.
See also
References
Further reading
- Viscusi, Kip (1988). "Regulatory Economics in Court: Analysis of NHTSA Decision Bumper Judge Scalia". Contemporary Laws and Problems . Retrieved July 2 2015 Claybrook's defense quotes Joan Claybrook about his tenure at NHTSA against the Government's failure comments by Supreme Court Justice Stephen Breyer, Joan. "Criticism Run Amok" (PDF) . Retrieved July 7 2015 . Ã,
Source of the article : Wikipedia
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