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Technical Paper

Injuries to Child in Automobile Collisions

Forty-six automobile collisions with 82 child occupants have been studied. Emphasis was placed on the mechanism of injury production and child collision kinematics. A number of case examples illustrate these injury patterns. Also included are example cases of the effects of collisions in pregnancy and cases of restrained children. Childhood growth characteristics as they affect injury patterns and restraint systems are discussed in detail. An analysis of current types of restraint systems is included and recommendations are made. Collision and comfort-convenience requirements of an “ideal” restraint system are listed.
Technical Paper

Facial Impact Response — A Comparison of the Hybrid III Dummy and Human Cadaver

Results indicate the need for a redesigned Hybrid III face capable of accurate force and acceleration measurements. New instrumentation and methods for facial fracture detection were developed, including the application of acoustic emissions. Force/ deflection information for the human cadaver head and the Hybrid III ATD were generated for the frontal, zygomatic, and maxillary regions.
Technical Paper

Interaction of Human Cadaver and Hybrid III Subjects with a Steering Assembly

Nineteen sled impact tests were conducted simulating a frontal collision exposure for an unrestrained driver. The deceleration sled buck configuration utilized the passenger compartment of a late model compact passenger vehicle, a rigid driver's seat, and a custom fabricated energy-absorbing steering column and wheel assembly. Sled impact velocities ranged from 24.1 to 42.6 km/hr. The purpose of the study was to investigate the kinematic and kinetic interaction of the driver and the energy-absorbing steering assembly and their relationship to the thoracic/abdominal injuries produced. The similarities and differences between human cadaver and anthropomorphic dummy subjects were quantified.
Technical Paper

Tolerance and Properties of Superficial Soft Tissues In Situ

Utilizing unembalmed cadaver test subjects, a series of tests was carried out to characterize quantitatively the resistance of the skin, the soft underlying tissue of the scalp, and certain other typical areas of the body to impact loading. The impacts were delivered by the use of an instrumented free-fall device similar to that previously employed for facial bone fracture experiments. In one group of tests, metal and glass edges were affixed to the impacting device to produce localized trauma under conditions which were standardized with respect to variables affecting the degree of the injury. In the second group of experiments, specimens of skin, together with underlying tissue of uniform thickness, were subjected to compressive impact between the parallel surfaces of the impacting weight and a heavy metal platen. From these latter experiments the force-time histories, coefficient of restitution, and hysteresis loops of load versus deflection were obtained for the specimens.
Technical Paper

Applications of Experimental Head Injury Research*

The types and mechanisms of head injury are reviewed, and then the findings of a UCLA study on the electrophysiology of primate concussion is presented. It was found that g loadings, as measured by a triaxial accelerometer attached to the skull of an impacted monkey, correlated well with severity of concussion. Deep and superficial cerebral electrodes were implanted to monitor electroencephalographic and impedance changes after concussion. Resistance dropped and capacitance rose in the impedance electrodes in direct proportion to the severity of concussion. Deep electroencephalographic recordings showed a high amplitude low frequency charfge in the reticular formation areas after impact. Superficial electroencephalographic recordings did not correlate with clinical states. Applications of these data are presented as they relate to the prevention and treatment of head injury.
Technical Paper

Impact Tolerance of the Skull and Face

Forces necessary for fracture under localized loading have been obtained experimentally for a number of regions of the head. Three of these, the frontal, temporoparietal, and zygomatic, have been studied in sufficient detail to establish that the tolerances are relatively independent of impulse duration, in contrast with the tolerance of the brain to closed-skull injury. Significantly lower average strength has been found for the female bone structure. Other regions reported upon more briefly are mandible, maxilla, and the laryngotracheal cartilages of the neck. Pressure distribution has been measured over the impact area, which has been 1 sq in. in these tests, and the relationship between applied force as measured and as predicted from a head accelerometer is examined.
Technical Paper

Impact Tolerance and Response of the Human Thorax

At the 1970 SAE International Automobile Safety Conference, the first experimental chest impact results from a new, continuing biomechanics research program were presented and compared with earlier studies performed elsewhere by one of the authors using a different technique. In this paper, additional work from the current program is documented. The general objective remains unchanged: To provide improved quantification of injury tolerance and thoracic mechanical response (force-time, deflection-time, and force-deflection relationships) for blunt sternal impact to the human cadaver. Fourteen additional unembalmed specimens of both sexes (ranging in age from 19-81 years, in weight from 117-180 lb, and in stature from 5 ft 1-1/2 in to 6 ft) have been exposed to midsternal, blunt impacts using a horizontal, elastic-cord propelled striker mass. Impact velocities were higher than those of the previous work, ranging from 14-32 mph.
Technical Paper

Injuries in Underride-Override Collisions - A Clinical Study

Automobiles damaged in collisions in which the main vehicle structure has been underridden or overridden were studied, as well as injuries to occupants of the automobiles. The parameters that affect injuries are listed and discussed, as are the effects of these parameters for each case example. Recommendations are made for modifications of passenger cars, trucks, trailers, and highway furniture to mitigate the severity of injury in underride-override collisions.
Technical Paper

Lower Extremity Injuries of Front Seat Occupants

A study was made of 290 collisions containing 464 front seat car occupants. Of the 405 injured occupants, 141 received their lower extremity injuries against the instrument panel. The occupant’s most serious injury was related to car model year, age of occupant, vehicle weight, and estimated impact speed. Statistically, a regression analysis shows a very strong correlation of these variables and collision injury. It is significant that the number of lower extremity injuries drops steeply for vehicles from 1957 through 1967. Rear seat occupant injuries were not considered in this paper.
Technical Paper

Injuries to Rear Seat Occupants in Automobile Collisions

A study was made of 54 collisions resulting in injuries to rear-seat occupants unrestrained by seatbelts. It was determined that children (who represent a disproportionate percentage of rear-seat occupants) tend to become airborne and to incur severe injuries against the windshield, miror, dashboard and header. Adults tend to injure the face and head against the front seat and to sustain typical leg fractures from trapping their feet under the front seat. The occupants seated at the outside edges of the rear seat sustain dangerous injuries from metal ashtrays and window crank handles out of proportion to the severity of the collision. All unrestrained rear-seat occupants add to the injuries of front-seat occupants by hurtling into them. Terminology to describe the types and severity of collisions is offered to facilitate medical and engineering evaluation of injuries. Recommendations are made for design changes to lessen hazards.
Technical Paper

Injury in Non-Fatal Accidents*

The research paper presented here is the result of an investigation by a medical-engineering team. The study applies techniques of experimental automobile-collision injury analysis to human injuries resulting from accidental collisions. The accident characteristics, observed injury patterns, and human kinematics are presented and analyzed. The study emphasizes injuries sustained from windshield glass. Present glass characteristics are discussed and suggestions based on the cases presented are made regarding future glass technology.
Technical Paper

Automotive Cardio-Thoracic Injuries: A Medical-Engineering Analysis

Cardio-thoracic injuries comprise a significant segment of the injuries sustained in automobile collisions. Because of the urgent need for additional information which can lead to prevention of these injuries, The Vehicle Trauma Research group at the UCLA School of Medicine has instituted a medical-engineering study of these injuries. The study has attempted to correlate pathophysiologic aspects of the injuries with the kinematics and biomechanics of the collision. Particular attention has been paid to the effects of restraining devices and the relationship of injuries of various wheel-column configurations including “energy absorbing” designs. Sixty-seven cases have been completely analyzed to date and are presented as a preliminary pilot study illustrating the value of this type of approach to auto collision injuries.
Technical Paper

Impact Tolerance and Response of the Human Thorax II

Previous studies of human thoracic injury tolerance and mechanical response to blunt, midsternal, anteroposterior impact loading were reported by the authors at the 1970 SAE International Automobile Safety Conference and at the Fifteenth Stapp Car Crash Conference. The present paper documents additional studies from this continuing research program and provides an expansion and refinement of the data base established by the earlier work. Twenty-three additional unembalmed cadavers were tested using basically the same equipment and procedures reported previously, but for which new combinations of impactor mass and velocity were used in addition to supplementing other data already presented. Specifically, the 43 lb/11 mph (19.5 kg/4.9m/s) and 51 lb/16 mph (23.1 kg/7.2 m/s) conditions were intercrossed and data obtained at 43 lb/16 mph (19.5 kg/7.2 m/s) and 51 lb/11 mph (23.1 kg/4.9 m/s).
Technical Paper

An Experimental Model for Closed Head Impact Injury

A series of blunt head impacts has been performed on stationary unembalmed human cadavers. The specimens were prepared to simulate realistic fluid pressures within the cerebrospinal fluid space and cerebral blood vessels. Translational acceleration-time histories of the head were recorded by biaxial accelerometers attached to the skull. Peak resultant head accelerations in excess of 3,000 m/s2 and pulse durations of 5 ms. or less were observed in a series of 10 experiments. The cerebral vascular system was perfused with a carbon particle tracer solution. Following impact, careful gross and microscopic pathologic studies of the cranial soft tissues were performed to assess vascular hemorrahage as represented by extravasation of tracer solution into the brain tissue. Data is presented describing the input forcing function, resultant head acceleration, and detailed necropsy findings.
Technical Paper

Comparative Knee Impact Response of Part 572 Dummy and Cadaver Subjects

The purpose of this paper is to present a comparison of whole body, target impingement knee impact response for a Part 572 dummy versus that for anthropometrically similar embalmed human cadavers. “Response” is defined here to include the impact force-time history as sensed by 1) femur load cells, and 2) impingement target load cells for the dummy and by the target load cells for the cadavers. The data presented demonstrate significantly higher peak forces and correspondingly shorter pulse durations for the dummy than for the companion cadaver subjects under similar test conditions and at all velocity levels investigated. For the dummy, the ratio of forces measured by the femur load cells to those measured by the impingement target load cells averaged eight tenths.
Technical Paper

Intracranial Pressure Relationships in the Protected and Unprotected Head

This paper represents a continuation of previous research on closed head impact in the human cadaver and an associated mathematical model. The long term goal of the study is to describe the relationships between head impact events which might be useful in understanding what takes place in the living human. In the current study, two different sets of experiments were conducted 1) sequential impacts on a single embalmed helmeted specimen and 2) impact experiments on individual helmeted unembalmed specimens. Impact parameters and intracranial pressures were measured and discussed. A finite element model is presented which can predict the intracranial pressures throughout the brain for the first 8 msec. It is apparent that the helmet prevents high magnitude, short duration intracranial pressures and that posterior pressures develop after the, acceleration phase and helmeted impacts.
Technical Paper

Injury Mechanisms in Rollover Collisions

This paper presents conclusions of a study of rollover collisions and the injuries resulting from them. The injury severity, the type of injury, the body region injured, the frequency of injury, and the injury mechanism are all indicated. The study includes statistics on both restrained and unrestrained occupants, and shows that ejected occupants usually sustain more severe injury than contained occupants. Several conclusions are presented as to automobile structures in relation to injury.
Technical Paper

Causes of Significant Injuries in Nonfatal Traffic Accidents

The Vehicular Trauma Research Group of the UCLA School of Medicine is currently conducting intensive studies of selected traffic accidents. Data is presented from an analysis of the first 150 traffic accidents studied. The role of vehicular design, mechanical failure and the performance of the new 1966 windshield in injury causation are discussed and illustrative examples are presented. The importance of detailed studies of traffic accidents is stressed as a method of yielding information not readily available by other methods of study. This approach is mandatory to evaluate new and pending vehicular design modifications and may be the only method of detecting and assessing the role of mechanical failure in traffic accident causation.
Technical Paper

Case Comparisons of Restrained and Nonrestrained Occupants and Related Injury Patterns

Restraining devices continue to be the most effective means of lessening injuries in automobile collisions. Evidence from the Trauma Research Group's case files illustrates how injury is avoided or minimized by use of lap, shoulder, and diagonal seat belts in several types of crashes, under various angles of impact. Prevention of fatal ejection, the improved chances a restrained driver has of retaining control of his car, and the attenuation of interior collision forces, such as result in jackknifing, are topics discussed, as well as the contribution of major automobile design improvements.