Crash test dummy
A crash test dummy, or simply dummy, is a full-scale anthropomorphic test device that simulates the dimensions, weight proportions and articulation of the human body during a traffic collision. Dummies are used by researchers, automobile and aircraft manufacturers to predict the injuries a person might sustain in a crash. Modern dummies are usually instrumented to record data such as velocity of impact, crushing force, bending, folding, or torque of the body, and deceleration rates during a collision.
Prior to the development of crash test dummies, automobile companies tested using human cadavers, animals and live volunteers. Cadavers have been used to modify different parts of a car, such as the seatbelt. This type of testing may provide more realistic test results than using a dummy, but it raises ethical dilemmas because human cadavers and animals are not able to consent to research studies. Animal testing is not prevalent today. Computational models of the human body are increasingly being used in the industry and research to complement the use of dummies as virtual tools.
There is a constant need for new testing because each new vehicle has a different design, and as technology changes ATDs must be developed to accurately test safety and efficacy.
History
On August 31, 1869, Mary Ward became the first recorded victim of an automobile accident; the car involved was steam-powered. Ward, of Parsonstown, Ireland, was thrown out of a motor vehicle and killed. Thirty years later, on September 13, 1899, Henry Bliss became North America's first motor vehicle fatality when hit while stepping off a New York City trolley.The need for a means of analyzing and mitigating the effects of motor vehicle accidents on humans was felt soon after commercial production of automobiles began in the late 1890s, and by the 1930s, when the automobile became a common part of daily life and the number of motor vehicle deaths were rising. Death rates had surpassed 15.6 fatalities per 100 million vehicle-miles continue to climb..
In 1930 cars had dashboards of rigid metal, non-collapsible steering columns, and protruding knobs, buttons, and levers. Without seat belts, passengers in a frontal collision could be hurled against the interior of the automobile or through the windshield. The vehicle body itself was rigid, and impact forces were transmitted directly to the vehicle occupants. As late as the 1950s, car manufacturers were on public record as saying that vehicle accidents simply could not be made survivable because the forces in a crash were too great.
Cadaver testing
's Wayne State University was the first to begin serious work on collecting data on the effects of high-speed collisions on the human body. In the late 1930s there was no reliable data on how the human body responds to the sudden, violent forces acting on it in an automobile accident. Furthermore, no effective tools existed to measure such responses.Biomechanics was a field barely in its infancy. It was therefore necessary to employ two types of test subjects in order to develop initial data sets.
The first test subjects were human cadavers. They were used to obtain fundamental information about the human body's ability to withstand the crushing and tearing forces typically experienced in a high-speed accident. To such an end, steel ball bearings were dropped on skulls, and bodies were dumped down unused elevator shafts onto steel plates. Cadavers fitted with crude accelerometers were strapped into automobiles and subjected to head-on collisions and vehicle rollovers.
Albert King's 1995 Journal of Trauma article, "Humanitarian Benefits of Cadaver Research on Injury Prevention", clearly states the value in human lives saved as a result of cadaver research. King's calculations indicate that as a result of design changes implemented up to 1987, cadaver research since saved 8,500 lives annually. He notes that for every cadaver used, each year 61 people survive due to wearing seat belts, 147 live due to air bags, and 68 survive windshield impact.
However, work with cadavers presented almost as many problems as it resolved. Not only were there the moral and ethical issues related to working with the dead, but there were also research concerns. The majority of cadavers available were older adult males who had died non-violent deaths; they did not represent a demographic cross-section of accident victims. Deceased accident victims could not be employed because any data that might be collected from such experimental subjects would be compromised by the cadaver's previous injuries. Since no two cadavers are the same, and since any specific part of a cadaver could only be used once, it was extremely difficult to achieve reliable comparison data. In addition, child cadavers were not only difficult to obtain, but both legal and public opinion made them effectively unusable. Moreover, as crash testing became more routine, suitable cadavers became increasingly scarce. As a result, biometric data were limited in extent and skewed toward the older males.
Very little attention has been paid to obesity and car crash studies, and it is hard to obtain an obese dummy for the experiment. Instead, human cadavers were used. Body weight is a vital factor when it comes to automobile accidents, and body mass is distributed differently in an obese person versus a non-obese person. At the University of Michigan, obese cadavers were tested and compared to non-obese cadavers, and they found that the obese cadavers had more injuries in their lower extremities. The researchers also suggested that an obese person could be protected by their fat almost causing a "cushioning effect."
The use of NDTs or Neutral Density Targets were implemented inside cadavers' brains to focus on the impact and separation of the brain and skull. NDTs provided detailed observations and allowed researchers to look at a specific area of the brain after the crash stimulation. It also helped to establish and develop the Finite Element model, initially developed to measure neck injuries for three-year-olds. A real child's neck was interpreted and incorporated into the FE model. FE models of the human head have become increasingly more important to the study of head injury.
Volunteer testing
Some researchers took it upon themselves to serve as crash test dummies. In 1954, USAF Colonel John Paul Stapp was propelled to over 1000 km/h on a rocket sled and stopped in 1.4 seconds. Lawrence Patrick, then a professor at Wayne State University, endured some 400 rides on a rocket sled in order to test the effects of rapid deceleration on the human body. He and his students allowed themselves to be hit in the chest with heavy metal pendulums, impacted in the face by pneumatically driven rotary hammers, and sprayed with shattered glass to simulate window implosion. While admitting that it made him "a little sore", Patrick has said that the research he and his students conducted was seminal in developing mathematical models against which further research could be compared. While data from live testing was valuable, human subjects could not withstand tests that exceeded a certain degree of physical injury. To gather information about the causes and prevention of injuries and fatalities would require a different kind of test subject.Animal testing
By the mid-1950s, the bulk of the information cadaver testing could provide had been collected. It was also necessary to collect data on accident survivability, research for which cadavers were woefully inadequate. In concert with the shortage of cadavers, this need forced researchers to seek other models. A description by Mary Roach of the Eighth Stapp Car Crash and Field Demonstration Conference shows the direction in which research had begun to move. "We saw chimpanzees riding rocket sleds, a bear on an impact swing...We observed a pig, anesthetized and placed in a sitting position on the swing in the harness, crashed into a deep-dish steering wheel at about 10 mph."One important research objective that could not be achieved with either cadavers or live humans was a means of reducing the injuries caused by impalement on the steering column. By 1964, over a million fatalities resulting from steering wheel impact had been recorded, a significant percentage of all fatalities; the introduction by General Motors in the early 1960s of the collapsible steering column reduced the risk of steering-wheel death by fifty percent.
Pigs were used for steering wheel impacts and other cabin collisions because they have an internal structure similar to humans, and can be easily placed correctly via sitting upright in the vehicle. The ability to sit upright was an important requirement for test animals so that another common fatal injury among human victims, decapitation, could be studied. Additionally, it was important for researchers to be able to determine to what extent cabin design needed to be modified to ensure optimal survival circumstances. For instance, a dashboard with too little padding or padding that was too stiff or too soft would not significantly reduce head injury over a dash with no padding at all. While knobs, levers, and buttons are essential in the operation of a vehicle, it was essential to determine which design modifications would best ensure that these elements did not tear or puncture victims in a crash. Rear-view mirror impact is a significant occurrence in a frontal collision: How should a mirror be built so that it is rigid enough to perform its task, yet of low injury risk if struck?
While work with cadavers had aroused some opposition, primarily from religious institutions, it was grudgingly accepted because the dead, being dead, felt no pain, and the indignity of their situations was directly related to easing the pain of the living. Animal research, on the other hand, aroused much greater passion. Animal rights groups such as the American Society for the Prevention of Cruelty to Animals were vehement in their protest, and while researchers such as Patrick supported animal testing because of its ability to produce reliable, applicable data, there was nonetheless a strong ethical unease about this process. Researchers at the University of Virginia have to call the cadaver's family and tell them what they are using their loved one for, after getting consent from the family. This seems to lessen ethical dilemmas in contrast to animal testing, because there is no sufficient way to get consent to use an animal.
Although animal test data were still more easily obtained than cadaver data, the anatomical differences between animals and people and the difficulty of employing adequate internal instrumentation limited their usefulness. Animal testing is no longer practiced by any of the major automobile makers; General Motors discontinued live testing in 1993 and other manufacturers followed suit shortly thereafter.
In 1980, animals such as bears and pigs were tested in car crash simulations. This led to moral dilemmas and was not the first time that animals were used in car crashes. In 1978, The University of Michigan Highway Safety Research Institute used baboons as a substitute for human test subjects in car crashes. Although there was the objection of animal cruelty that arose, there was also the controversy of how they are similar to humans and can be used as a sufficient testing substitution for us. The researchers did not end up stopping the use of baboons because of moral objections, but instead stopped because they had collected sufficient data. The moral inputs from other people and organizations were inconsistent, which caused implications when deciding to ban healthy animals from research testing. The animals were put under anesthesia, so there was no pain put upon them, but the aftereffects cannot justify this. General Motors used animals for testing, and also suggested that they put the animals under anesthesia and then would kill the animals after completing the testing.
Although the University of Michigan Highway Safety Research Institute did get bad publicity, it was suggested that this is not the reason why they stopped using baboons. The University of Michigan's mission was to create safer cars for human use. In order to reach this goal, research and testing is inevitable. The cruelty and the moral dilemmas of animal testing did not trump researchers still using them as subjects. They reasoned that biomechanics data are needed for an experiment like this, which will lead to safer cars. Years later, animal testing ceased and instead an instrumented dummy was created as a replacement. In 1978, animals were their only subjects that could be a reliable substitution for the human being. The disadvantage, though, to using an instrumented dummy or a human cadaver, is that the tissue is not alive and will not elicit the same response as a live animal. By 1991, the use of animals in vehicle collision tests was in decline because of advances in computers and technology. It is difficult to use cadavers instead of animals because of human rights, and it is difficult to obtain permission from the families of the deceased. Consent for a research and testing can occur only if the person responsible for giving consent is mentally competent and comprehends the research and testing procedures fully.