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Technical Paper

The Translational Energy Criteria: A Validation Study for Non-Fracture Head Impacts

1997-11-12
973337
The development of the Translations Energy Criteria (TEC) has been underway for the last fifteen years. This criteria addresses brain contusion and skull fracture in the Anterior-Posterior (A-P), Left-Right (L-R), and Superior-Inferior (S-I) directions. The object of this strudy was to evaluate the ability of the TEC to predict non-fracture type injuries to the brain in the L-R and A-P directions up to the level of “serious.” Six unembalmed human cadavers were subjected to one head impact each. Tests one through three were frontal impacts, performed at 1.6, 3.9 and 6.7 m/s respectively. Tests four through six were lateral impacts, performed at 1.9, 3.8 and 6.1 m/s respectively. The impactor weighed 9.05 kg and was fitted with either a rigid or padded surface. The brain was repressurized and the head instrumented with two tri-axial linear accelerometer arrays and one angular velocity transducer. Two high speed motion picture views (1000 frames per second) were taken for each test.
Technical Paper

Biomechanical Analysis of Tractor Induced Head Injury

1994-09-01
941726
Head injury is a serious threat to lives of people working around farm machinery. The consequence of head injuries are costly, paralytic, and often fatal. Clinical and biomechanical data on head injuries are reviewed and their application in the analysis of head injury risk associated with farm tractor discussed. A significant proportion of tractor-related injuries and deaths to adults, as well as children, is due directly or indirectly to head injury. An improved injury reporting program and biomechanical studies of human response to tractor rollover, runover, and falls, are needed to understand mechanisms of the associated head injury.
Technical Paper

Spinal Cord Injuries to Children in Real World Accidents

1993-11-01
933100
In the last twelve years, the overwhelming effectiveness of restraining children in the United States, Canada and Europe has been proven in reducing death and injury in automobile accidents. Despite the proven benefits of restraining children, one type of injury has not been prevented. This paper is an analysis of stretch injuries to the spinal cord in the upper thoracic or cervical spine. This paper discusses, in general, spinal cord injuries from a biomechanical point of view. The relationship between various loading conditions and the resulting types of spinal cord injuries is discussed. This paper also examines seven real world automobile accidents. Information for each case includes: vehicles involved, type of roadway, crash Delta-V, occupant direction of motion, restraint type, injuries to occupants, and anthropometry of child with spinal cord injury. A description and location of each spinal cord injury that occurred at the time of the accident is discussed.
Technical Paper

Abdominal Trauma-Review, Response, and Criteria

1985-04-01
851720
As an aid to designing an abdominal insert for anthropomorphic dummies, a study of abdominal trauma factors has been made. Questions regarding human impact response and tolerance were answered within the framework of primate scaling. Results of subhuman primate impacts and primate anthropometry were combined to produce injury criteria for frontal and lateral abdominal impacts. Impact response for the frontal and lateral directions was also defined for humans. The primate impact data used in the study was obtained in the early 1970's in laboratory tests utilizing a specially designed “air gun”. This test set up emphasizes reproducibility and control. Human lateral abdominal impact data first published by Walfisch et al., in 1980 were reanalyzed and used to check the primate scaling. Significant differences in impact injury tolerances for various abdominal locations were noted and detailed.
Technical Paper

Biomechanical Evaluation of Steering Wheel Design

1982-02-01
820478
In a crash, impact against the steering assembly can be a major cause of serious and fatal injury to drivers. But the interrelationship between injury protection and factors of surface area, configuration, padding, relative position of the spokes, and number and stiffness of spokes and rim is not clear. This paper reports a series of high-G sled tests conducted with anesthetized animal subjects in 30 mph impacts at 30 G peaks. A total of eight tests were conducted, five utilizing pig subjects, one a female chimpanzee, one an anthropomorphic dummy, and one test with no subject. Instrumentation included closed circuit TV, a tri-axial load cell mounted between the steering wheel and column, seat belt load measurement, six Photo-Sonics 1000 fps motion picture cameras, and poloroid photography. Medical monitoring pre, during and post-impact was followed by gross and microscopic tissue examination.
Technical Paper

Biomechanical Analysis of Swimming Pool Neck Injuries

1979-02-01
790137
This paper presents an analysis of 67 neck injuries incurred in diving and sliding accidents in swimming pools. The accidents were investigated to establish the appropriate medical and mechanical factors involved. A mathematical model was developed to allow the prediction of the trajectory and velocity of the subjects prior to their injury. Nine of the accidents were selected for real life simulation. The simulation included the selection of test subjects of similar physical build to the accident victims who then performed the maneuvers leading to the injury, but in deeper water. High speed movies (200 frames per second) were taken, above and below the water, to measure the motion. A frame by frame analysis provided data to determine the trajectory and velocity profiles of the test subject. The maneuvers studied included diving from the pool edge, diving from various board types and sliding down various sliding board configurations.
Technical Paper

Crashworthiness Analysis of Field Investigation of Business Aircraft Accidents

1979-02-01
790587
Business and executive aviation represent a combined total of over 40% of the general aviation fleet, but (1977) accounted for only 8.37% of all general aviation accidents recorded. During the period 1964-1977 some 7,351 aircraft engaged in business flying, and 883 in corporate/executive operations, were involved in accidents reported by the NTSB. These accidents were reviewed utilizing the University of Michigan Computerized Accident Files to provide an overall view of the incidence and nature of business/executive aircraft accidents relative to occupant crash injuries. In addition more detailed case studies of selected accidents investigated including a Lear Jet 25B, Cessna 421, Beech Volpar Model 18, and Ted Smith Aerostar 601, are provided to illustrate specific types of crashworthiness, occupant protection, or post-crash emergency egress findings applicable to business/executive operations. Post-crash fire was reported in 29 cases (16.3%) during the 3-year period (1975-1977).
Technical Paper

General Aviation Crash Survivability

1978-02-01
780017
Statistics indicate that during the past decade (1967-1976) the number of general aviation aircraft involved in an accident is equivalent to at least 38% of the total U.S. production during that period. Estimates that an aircraft will be involved in an accident over a 20 year life range are as high as 60-70%. Recognition of this probability has led to crashworthiness and occupant survivability “packaging” design concepts as offering the most realistic approach to reduction of serious and fatal injuries when an accident occurs. This paper reviews and illustrates current general aviation aircraft accident experience relative to occupant impact injury and damage indexes, and provides new data relative to current-generation aircraft.
Technical Paper

Protection of Child Occupants in Automobile Crashes

1978-02-01
780904
Detailed investigations of automobile crashes in which children under 10 years old were passengers were carried out. The purpose of this study was to investigate the injury patterns of restrained and unrestrained children and to assess the performance of child restraint systems in real world crashes. Crashes which occurred mainly in Washtenaw and Oakland counties of the state of Michigan were surveyed. A total of 348 vehicle crashes involving 494 children less than 10 years old were identified. Forty eight crashes involving 63 children were selected for in-depth investigation. 37% of the children in the investigated cases were restrained by an adult lap belt or a child restraint. It was found that only 4.7% of the children in the overall sample were restrained. Both adult seat belts and child restraints (when used) were found to be effective in reducing injuries in crashes. Head and facial injuries were found to be the most common form of injury to children.
Technical Paper

Study of Human Impact Tolerance Using Investigations and Simulations of Free-Falls

1977-02-01
770915
A study of free-fall accidents and resulting injuries was conducted to determine how useful these types of data could be in establishing human injury tolerance limits. “Tolerance” was examined primarily for children at two levels - reversible injury and threat to survival. The specific objectives were to investigate specific free-falls in sufficient depth to permit biomedical or mathematical reconstruction of the fall, simulate selected free-falls to estimate impact response, and compare predicted responses with observed injuries as a means of estimating human tolerance levels. From more than 2100 reported free-falls, 110 were investigated on-site. Seven head-first and three feet-first falls were then simulated using the MVMA 2-D Crash Victim Simulator. Newspaper reports of free-falls showed that males fell six times as often as females and most often while at work. Children fell from windows and balconies more often than from any other hazard.
Technical Paper

Civil Aircraft Restraint Systems: State-of-the-Art Evaluation of Standards, Experimental Data, and Accident Experience

1977-02-01
770154
The importance of crashworthiness and the role of restraint systems in occupant impact protection in U.S. civil aircraft design is being increasingly recognized. Current estimates of the number of fatalities which could be prevented annually in survivable accidents range from 33 to 94%. This study reviews the development of existing Federal Aviation Administration restraint system standards from the first requirement for safety belts in the Air Commerce Regulations of 1926 to present 14 CFR 1.1. The FAA and industry standards are critically evaluated for Parts 23 (small airplanes), 25 (air transports), 27 (rotorcraft), and 29 (transport category rotorcraft). State-of-the-art developments, including an overview of previous accident experience, results of experimental studies, comparison with other standards, and primary data sources are provided.
Technical Paper

Performance Evaluation of Child Dummies and Baboons in Child Restraint Systems in a Systematized Crash Environment

1975-02-01
751153
A three-part program was undertaken to establish an appropriate means of evaluating child restraints in automobile crashes. A standard seat was designed to provide a reproducible test base on which to evaluate child restraint systems in dynamic testing. Developmental and evaluation data are presented, including child restraint performance tests. Results showed the standard seat to be a durable, repeatable, and economical test platform which provides a realistic base for evaluation of child restraint systems. Commercially available three- and six-year-old child dummies were evaluated for their anthropometric measurements and dynamic response characteristics in pendulum impact tests and simulated crashes in representative automobile-child seat restraint environments. Simulated crashes included 20 and 30 mph frontal and 20 mph side impacts on automobile and specially designed bench seats. Two types of child seats, the G. M.
Technical Paper

Crashworthiness Investigation of General Aviation Accidents

1975-02-01
750537
General aviation accident investigations can provide valuable data to the design engineer concerning the crash performance of current models and can indicate needed improvements for occupant protection in future aircraft. Current statistics and the historical background of major investigations during the past 65 years are provided. A five-year study of general aviation accidents occurring in the State of Michigan is used as a basis to illustrate recent findings relative to occupant injury mechanisms, relative crash protection, and crashworthiness performance of current models of aircraft. Results indicate that the degree of structural damage may not relate to the degree of occupant injury when the cabin area remains relatively intact. A primary requirement is documented for adequate upper-torso restraint for all occupants, and the excellent crash performance of such a system is described.
Technical Paper

Occupant Injury Assessment Criteria

1975-02-01
750914
This paper is a brief review of the complex subject of human injury mechanisms and impact tolerance. Automotive accident-related injury patterns are briefly described and the status of knowledge in the biomechanics of trauma of the head, neck, chest, abdomen and extremities is discussed.
Technical Paper

Occupant Impact Injury Tolerances for Aircraft Crashworthiness Design

1971-02-01
710406
Human impact injury and survival tolerance levels for various crash conditions are presented on the basis of currently available biomedical and biomechanical knowledge. Consideration of physical factors influencing trauma-including body orientation, restraint system, magnitude, distribution, and time duration of deceleration-are summarized, as well as tabulations and sources of data for both whole body and regional impact tolerances. These biological data concerning human impact tolerances are provided as guidelines for improved engineering design of general aviation crashworthiness.
Technical Paper

Door Crashworthiness Criteria

1971-02-01
710864
A study of the biomechanical factors concerned with the design of side structures and doors for crashworthiness has been made. Questions regarding optimum stiffness, location of reinforcing members, effect of armrests, and padding have been answered within the framework of injury criteria models. Results of animal studies, cadaver studies, and anthropometric dummies have been combined to produce injury criteria for lateral impacts to the head, thorax, and abdomen. Impacts were applied utilizing a specially designed “air gun” in a laboratory environment emphasizing reproducibility and control. Full-scale crash simulations were performed on an impact sled to verify the results of the more specialized tests and analyses. Scaled models of current production doors were used in the animal series. Scaling relationships for various species of animals have been developed and extrapolated to man. Significant differences in right and left side tolerances to impact were noted and detailed.
Technical Paper

Bioengineering of Impact Survival in Business Aircraft

1969-02-01
690335
Aircraft used for business (executive corporate transportation or personal business) and utility purposes now represent about one-third of the total United States aircraft inventory. Data from accident investigation of business aircraft involved in survivable accidents indicate serious injuries and fatality to the occupants occur most frequently as a result of the unprotected head and neck or chest flailing in contact with aircraft controls, instrument panel, or structure. Improvement of current aircraft to provide increased occupant safety and survival during crash impacts is both necessary and feasible. Design considerations include folding seat back locks to prevent collapse, increased seat tie-down to structure, instrument panels and glare shields designed to absorb energy through structural design and padding, stronger seat structure, lateral protection, design and packaging of knobs and projections to minimize injury in contact, and installation of upper torso restraint.
Technical Paper

Impact Injury to the Pregnant Female and Fetus in Lap Belt Restraint

1966-02-01
660801
Although it has been well established that the lap (seat) belt offers considerable protection against injury or death in crash environments, there has long been controversy over the injury potential to the pregnant female. This question is of importance in consideration of restraint and seat protective environments for both aircraft and automotive vehicles. Most of the 4 million pregnant women per year in the United States travel by automobile, with a large number traveling by Commercial Civil Aircraft or the Military Air Transport Service. Thus a sizeable population is involved. This combined study by the Civil Aeromedical Institute, F. A. A., 6571st Aeromedical Research Laboratory, Holloman AFB, and the University of Oklahoma School of Medicine, has been concerned with the clinical, experimental, and applied aspects.
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