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The objective of the study was to investigate the biomechanical response of the intact cranium. Unembalmed human cadavers were used in the study. The specimens were transected at the base of the skull leaving the intracranial contents intact; x-ray and computed tomography (CT) scans were obtained. They were fixed in a specially designed frame at the auditory meatus level and placed on the platform of an electrohydraulic testing device via a six-axis load cell. Following radiography, quasistatic loading to failure was applied to one of the following sites: frontal, vertex, parietal, temporal, or occipital. Retroreflective targets were placed in two mutually orthogonal planes to record the localized temporal kinematics. Applied load and piston displacement, and the output generalized force (and moment) histories were recorded using a modular digital data acquisition system. After the test, x-ray and CT images were obtained, and defleshing was done.

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.

Past research has shown that although occupants often survive crash impacts of business jet aircraft, they are often injured either in the course of egress or because they are unable to evacuate. A physical task analysis was performed to evaluate procedures for emergency egress from a typical business jet to demonstrate how possible human factors problems can be identified. First, the tasks required for the flight crew to evacuate via all possible routes were determined. Second, each task was divided into a series of physical elements, such as reach and grasp, corresponding to each movement or exertion. Third, physical aspects of the aircraft affecting performance of each element such as location and force, were measured. The physical requirements of each element were compared with available human factors data, to rate its difficulty. Selected aspects of the analysis are discussed.

Accurate data on the body dimensions of truck drivers are needed and such data are not presently available. This paper provides basic source data and an anthropometrical overview of the usefulness and limitations of existing data bases; discusses the influence of population factors, including age, sex, and demographic variables; and reviews population sampling problems. Heavy truck drivers as a whole appear to represent a physically different population from that of either the U.S. general population or other professional groups. Future anthropometric surveys must provide information for improved accommodation for the increasing range of physical size of users, and for obtaining data more useful to engineers involved in heavy truck interior cab design.

Empirical models are presented which predict the threespace position of the torso when responding to reaches with the right arm. Models were derived which specify torso position in terms of the spacial location of 10 surface markers. These markers were positioned over palpable skeletal points of the spine and shoulder girdle. The necessary data were obtained through photogrammetric procedures utilizing four orthogonal cameras. The independent (input) variables to these models are the coordinates of the reach target. A supplementary, slightly more accurate, set of models was also derived in which the set of independent variables was enlarged to include the anthropometric dimensions of the subject. The second, concurrent phase of the analysis resulted in the derivation of a set of models which describes the configuration of the internal, torso skeletal system.

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.

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.

Knowledge of human impact tolerance(s) is a basic consideration in the improved design of air transport seat-restraint systems and occupant crash protection. This paper discusses biological factors which influence tolerance, defines tolerance levels, variables including whole body and regional impact, and effect of seat and body orientation. It is concluded that the ultimate inertial forces on the occupant specified in FAR 25.561 are not based upon human tolerance considerations; that human impact survival is estimated to be four to ten times the voluntary levels cited; that improved occupant protection requires dynamically tested structural improvements: and that currently available technology such as the NASA air transport seat, or rear-facing seats, should be utilized.

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.

Basic physical characteristics of the neck have been defined which have application to the design of biomechanical models, anthropometric dummies, and occupant crash protection devices. The study was performed using a group of 180 volunteers chosen on the basis of sex, age (18-74 years), and stature. Measurements from each subject included anthropometry, cervical range-of-motion (observed with both x-rays and photographs), the dynamic response of the cervical flexor and extensor muscles to a controlled jerk, and the maximum voluntary strength of the cervical muscles. Data are presented in tabular and graphic form for total range-of-motion, cervical muscle reflex time, decelerations of the head, muscle activation time, and cervical muscle strength. The range-of-motion of females was found to average 1-12 deg greater than that of males, depending upon age, and a definite degradation in range-of-motion was observed with increasing age.

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.

Properties of the human neck which may influence a person's susceptibility to “whiplash” injury during lateral impact have been studied in 96 normal subjects. Subjects were chosen on the basis of age, sex, and stature and data were grouped into six primary categories based on sex (F, M) and age (18-24, 35-44, 62-74). The data include: measures of head, neck and body anthropometry in standing and simulated automotive seating positions, three-dimensional range of motion of the head and neck, head/neck response to low-level acceleration, and both stretch reflex time and voluntary isometric muscle force in the lateral direction. Reflex times are found to vary from about 30 to 70 ms with young and middle aged persons having faster times than older persons, and females having faster times than males. Muscle strength decreases with age and males are, on the average, stronger than females.

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.

Both the inverted-Y yoke torso harness with inertia reel and the air bag restraint system have had extensive independent development for some time by several engineering and research organizations for both aviation and ground vehicle occupant protection. The research reported in this paper consists of the first biomechanical primate evaluation of these concepts as experimentally adapted for possible automotive use. These tests are a continuation of a study involving the relative impact protection and effectiveness of major restraint systems utilized in general aviation aircraft and in limited automotive use. The objective of this test series was to determine how much protection those advanced restraint concepts provided; to obtain preliminary biomechanical and physiological data; to identify problems of technique and applications in occupant protection; and to provide an initial basis for direction of future test requirements.