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1971-02-01
Technical Paper
710021
J. A. Pflug
Crash testing has revealed dynamic problems with present designs for air bag passive restraints which must be resolved. Out-of-position occupants can restrict deployment of the air bag or affect its restraint action. In rollover and side impact accidents, today's air bag offers only minimal restraint. Accordingly, it appears essential to use the lap belt, in combination with air bags, to achieve an improved restraint system over current systems when usage rates and effectiveness are considered. The noise level created by air bag actuation may exceed tolerance levels in some humans. Inadvertent deployment of air bags could compromise the driver's control of the vehicle. These and other technical problems must be resolved before such systems are furnished in automobiles to be sold to the public.
1971-02-01
Technical Paper
710017
J. T. Johnson, R. E. McComb, T. F. McDonnell, D. R. Trowbridge
Engineering design features of three types of energy sources for the Inflatable Occupant Restraint System (IORS) are reviewed. These systems use: 1. Compressed gas 2. Propellant 3. A combination of compressed gas and propellant as a power source for the inflation of the restraint cushion. An analysis is presented of each system with advantages and disadvantages related to specific design parameters. The analysis is restricted to present state-of-the-art systems. It is also based on strictly engineering design features with recognition that product cost, patent position, and other intangibles are factors in final energy source selection. The analysis indicates several important advantages of the combined propellant-air (hybrid) system over one or both of the other two. These are: 1. Ability to obtain nontoxic gases with currently developed propellants. 2. More flexibility in control of gas thermodynamics. 3. The small propellant weight requirements.
1971-02-01
Technical Paper
710016
Trevor O. Jones, Oliver T. McCarter
A general overview of crash sensor approaches and development is presented including: Passive Inflatable Occupant Restraint System (PIORS) components, time-history of an impact, crash detector requirements and characteristics, and reliability considerations.
1971-02-01
Technical Paper
710015
F. J. Irish, R. A. Potter, R. D. McKenzie
This paper discusses the design of an automobile air cushion restraint system which will provide adequate occupant protection. The extensive process employed in the design of such a system is presented; systems analysis, engineering, testing, and evaluation are the major points of the process. The program is intended to provide low-cost safety methods, and to provide a basis for future development of more improved safety systems.
1971-02-01
Technical Paper
710540
F. F. Timpner
This paper shows how to evaluate the impact between two different size vehicles with different energy-absorbing bumper systems. A pendulum will correlate with a barrier for head-on impacts, but not for corner impacts.
1971-02-01
Technical Paper
710503
Kenneth F. Vander Leest
How safe are the products we use? Today, people are constantly being alerted to the many dangers which exist in our everyday products, whether it be machinery or toy. Who is to blame and how can the public be protected. Governments, both federal and state, are responding to the public's demand for safer products; however, there is yet much progress to be made by technology to give us products which are safe for our everyday use.
1971-02-01
Technical Paper
710508
James F. Arndt
Over the past 50 years, an estimated 30,000 tractor operators have been accidentally crushed under their overturned vehicles. During that time, stability, preventive devices, and education have been tried to reduce the number of such accidents. Within the past 15 years, worldwide activity has been concentrated on developing adequate roll-over protective structures (ROPS) for operator protection. In order to measure the adequacy of the structures, various worldwide performance standards have been created. The latest include those of the SAE, which recognizes the need for a ROPS to absorb energy in order to minimize injury to the operator.
1971-02-01
Technical Paper
710509
William P. Macarus
Plastic analysis type of analytical calculations are included in this paper as a guide for designers to size Rollover Protective Structures to meet SAE J-395. Basic design considerations are given including material selection, brittle failures, local buckling, and allowable deflections.
1971-02-01
Technical Paper
710297
Josef R. Smith
The anatomy of the human respiratory system is detailed. The function of the entire system is shown from inspiration to expiration. Equations are given to illustrate flow-pressure relationships in the airways. Specifics of gas transfer are shown. All these details of physiology and function are necessary for an understanding of the effects of air pollution upon the human respiratory system.
1971-02-01
Technical Paper
710277
R. A. DePaul
Gears fail or are damaged on occasion by impact fatigue loading. This study involves an evaluation of the resistance of commonly used gear steels to impact fatigue failure. A specially designed impact fatigue specimen and testing device were used to evaluate nine carburizing steels (SAE 4118, 4620, 4626, 4718, 4817, 8620, 8822, EX-1, and the European 16MnCr5) and three nitriding steels (Nitralloy G, Nitralloy N, and 5Ni-2Al). The relative impact fatigue resistances of the steels are discussed as well as the influences of such heat treatment variables as high carbon potential, high temperature carburizing, and refrigeration. In general, impact fatigue resistance was independent of core strength but improved with increasing nickel content in the nitrided steels as well as the carburized steels. Lowering retained austenite by refrigeration was found to be detrimental to impact fatigue resistance.
1971-02-01
Technical Paper
710078
R. W. McLay, F. J. Blackstone, P. K. Das
An energy-absorbing restraint system that limits the accelerations of a passenger in a forward auto crash to 20 g's is presented. The device absorbs energy through the continuous bending of a steel wire. Results of an elastic-plastic analysis of the device indicate that it closely approximates a constant force energy absorber; the force is only a weak function of velocity. Preliminary results from drop tests and high-speed impact tests to 100 mph indicate that the absorber can limit acceleration to a specified value. The results of two tests in which the device was used to restrain a volunteer during a head-on crash are presented. In each crash a vehicle driven at 50 mph impacted a parked vehicle. The results show that the restraint system protects a man in a forward crash by limiting his accelerations to a level below the threshold of injury for the vital organs.
1971-02-01
Technical Paper
710079
L. M. Patrick, K. R. Trosien
The paper gives an evaluation of the performance of lap and shoulder belt restraint systems currently being used in American-built automobiles. Comparisons are made of the response characteristics of a volunteer, an anthropometric dummy, and a cadaver when subjected to identical collision environments while wearing a three or four point torso restraint system as occupants of the right front seat. Simulated frontal force barrier collisions in a modified automobile provided the realistic environment for the restraint system performance study. Human tolerances, interior vehicle geometry, and the interaction of the restrained occupant with the vehicle during the collision are reported in detail.
1971-02-01
Technical Paper
710076
Donald F. Huelke, Harold W. Sherman
Ejection of car occupants through door openings has been markedly reduced in the new model cars. However, cases have now been found where car occupants are being ejected through the side door glass opening or directly through the side glass. Twenty-one cases of ejection through the side glass are described.
1971-02-01
Technical Paper
710077
W. D. Nelson
Lap-shoulder belts, although infrequently used by vehicle occupants, are demonstrating a remarkably high reduction of injury in collisions where they were used. A search was made for all collisions in the GM files where at least one occupant was wearing the lap-shoulder belt combination restraint. Of the 160 cases found for this study, 60% of the vehicles had heavy damage of the type often associated with occupant injury: however, 99% of the lap-shoulder belt users either had no-injury or only minor injury. The only two fatalities found in the study involved accidents occurring under unusual circumstances. This paper describes 18 of the most severe damage and/or injury cases by means of photographs and collision descriptions. Some grouping of body injuries is also listed. These data illustrate that the use of different occupant restraint configurations (unrestrained, lap belt, and lap-shoulder belt) affect the severity of injuries to various body areas.
1971-02-01
Technical Paper
710182
W.C. House, W.J. Eggington, C.A. Lysdale
The characteristics of the supporting air cushion system are key to the cross-country mobility and overwater performance of Air Cushion Vehicles and Surface Effect Ships. The direction of developments in this technology are discussed, and the primary cushion design variables are identified. The historical sequence of air cushion development is reviewed, and it is concluded that current and future advancement will be based on “3rd generation” systems, in which the cushion system design is tailored to the specific application.
1971-02-01
Technical Paper
710487
Alan E. Diehl
A simple mathematical model was developed to estimate benefit-to-cost ratios of alternative safety devices. The “Benefit” is the expected decrease in accident losses, while “Cost” includes the expense of the device plus maintenance and useful load penalty. This model permits the manufacturers and operators to select the most effective items. Realizing that the majority of accidents involve pilot error, the strong and weak points of contemporary cockpit design are described. Several human engineering improvements are proposed.
1971-02-01
Technical Paper
710455
E. E. Glanz
Aircraft equipped with computerized Area Navigation Systems have created the need for an entirely new air traffic control environment. This paper will highlight problems encountered as the ATC system begins its evolution toward area navigation, and will suggest operational techniques favorable to a total area navigation ATC environment. Conventional interfaces are no longer useful. Independent systems (computer, controller, pilot, route structure, and aircraft) meet in the cockpit, but satisfactory communications have not been established. Pilot reaction indicates that the information is not now properly presented in the cockpit. Attempts to solve these interface problems have indicated that the solution lies in comprehensive software programs and clear situation displays for the pilot.
1971-02-01
Technical Paper
710456
A. B. Winick, D. M. Brandewie
The need to improve the efficiency and capacity of the Air Traffic Control and Navigation System has placed greater emphasis on the functional integration of subsystems which have been treated independently in the past. This paper presents results of limited test programs designed to explore the relationship of terminal area navigation and the air traffic control system, and to show the benefits of an optimum combination of both functions. The need for further analysis is indicated with respect to carrying out the third generation system design postulated by the DOT Air Traffic Control Advisory Committee. It is concluded that functional integration of ATC and navigation in the terminal area presents the greatest challenge. In other areas, such as enroute, the availability of new, integrated avionics systems provides an expanded operational capability.
1971-02-01
Technical Paper
710632
T. D. Sherard
The “real world” of highway truck operation sometimes differs from the technical world of simulation models, laboratory and proving ground tests and mathematical equations. At this time this is a matter of real concern. Federal standards now being proposed and effected appear to be based on the maximum performance-or greater-that can be built into a vehicle fresh off the production line. Generally speaking, when the truck or trailer comes off the production line it is, or should be, at the peak of its lifetime performance. Therefore, it is disturbing to see a trend, at state and federal levels, to impose new truck standards or standards even more severe on vehicles in actual operation, especially combinations of vehicles whose individual units, even though adequate when tested alone, cannot, when combined, attain such individual unit standards-that is, without exorbitant costs which will eliminate them entirely from the highways.
1971-02-01
Technical Paper
710644
W. E. F. Rupprecht, M. E. Winquist
The human factor will always be a deterrent to achievement of 100% safety in automobiles, but new design and materials have considerably narrowed the margin of risk in highway accidents. This article considers the contributions made by the chemical industry in providing materials suitable for this purpose. Improvements in crash padding, hydraulic fluids, and gas tanks have greatly reduced injuries attributable to impact, fire, and brake failure. The close cooperation of the automotive and chemical industries is duly credited for these safety efforts. Emphasis is placed on the need for integration of inspection, driver education, highway design, and traffic laws with enforcing agencies in order to perfect overall in-use protection.
1971-02-01
Technical Paper
710848
Richard G. Snyder, Don B. Chaffin, Rodney K. Schutz
Abstract The object of this study has been to develop a quantitative description of the mobility of the human torso, including the shoulder girdle, neck, thoracic and lumbar vertebral column, and pelvis. This has been accomplished by a systematic multidisciplinary investigation involving techniques of cadaver dissection and measurement, utilizing cineradiofluoroscopy for joint center of rotation location, anthropometry, radiography, and photogrammetry for selected positions and motions of living subjects, and computer analysis. Positional and dimensional data were obtained for 72 anthropometric dimensions on 28 living male subjects statistically representative of the 1967 USAF anthropometric survey of 3542 rated officers, including bone lengths of the extremities and vertebral landmarks. Normal excursion of these limbs was measured in the living, utilizing the landmarks established in initial cadaver dissection.
1971-02-01
Technical Paper
710850
Albert I. King, Rolf H. Eppinger, Warren M. Crosby, L. Clarke Stout
A series of 24 pregnant baboons was impacted under similar conditions. The only major variable was the difference in maternal restraint. The fetal death rate of 8.3% (1/12) among maternal animals impacted with three-point restraint was significantly different from five fetal deaths among 10 maternal animals impacted under lap belt restraint alone (p < 0.05). It is concluded that shoulder harness restraint should be recommended for use by pregnant travelers as being significantly more protective of fetal welfare when compared with lap belt restraint alone.
1971-02-01
Technical Paper
710847
J. F. Sprouffske, W. H. Muzzy, Edwin M. Trout, Thomas D. Clarke, C. D. Gragg
Abstract The objectives of this study were twofold: to determine if the variability of dummy performance could be reduced by refinishing the joints and bearing surfaces of the dummy; and to establish a technique for preparing dummies for dynamic tests and measurements to be made for evaluating dummy performance. The testing was divided into three groups. The first phase evaluated the effect on data reproducibility by adjusting the dummy only before a complete series; the next phase evaluated the effect of adjusting before each run; the third phase evaluated the effect of changing the sled deceleration level. In each phase the lap belt, seat pan down, and seat pan forward loads were obtained. The data consist of graphs delineating the alteration on these loads during consecutive runs in each of the above phases. In addition, the loads were plotted versus the sled deceleration level and regression lines calculated.
1971-02-01
Technical Paper
710849
D. H. Robbins, R. G. Snyder, J. H. McElhaney, V. L. Roberts
Abstract A study has been conducted as an initial step in determining the differences observed between the motions of a living human impact sled test subject and a dummy test subject. The mechanism which is proposed for accomplishing this is the HSRI Two-Dimensional Mathematical Crash Victim Simulator. A series of measurements were taken on human test subjects, including classical and nonclassical anthropometric measurements, range of motion measurements for the joints, and maximum foot force measurements. A series of mathematical expressions has been used to predict body segment weight, centers of gravity, and moments of inertia using the results of the various body measurements. It was then possible to prepare a data set for use with the mathematical model.
1971-02-01
Technical Paper
710881
John Versace
Abstract The SAE Severity Index is supposed to be an approximation to tolerance limit data, but there are incongruities in its derivation which renders the formula unsupportable. The same logic on which the Severity Index appears to be based can be used to support a wide range of possible values for the exponent on the acceleration, including infinity. This inconsistency results because necessary distinctions have not been made between: the formula for a fitted approximation to the tolerance limit data, the scaling of severity as such, and the measure of the acceleration magnitude of a pulse, the “effective acceleration.” It is recommended that a formula which more literally follows from the tolerance limit data be adopted. In the long run, however, it is believed that a much more appropriate measure of injury severity would result from processing head impact data in such a way as to reflect the probable degree of brain injury.
1971-02-01
Technical Paper
710879
A. Slattenschek, W. Tauffkirchen, G. Benedikter
Abstract The requirements made with respect to the phantom head, as well as the impact assessment method in order to obtain realistic test results are indicated. Particular attention is given to the possible measuring errors occurring when using unsuitable phantom bodies. In dealing with the impact assessment methods, those according to C. W. Gadd and the Vienna Institute of Technology are compared with regard to their different assessment and properties.
1971-02-01
Technical Paper
710878
George T. Tindall, Kinjiro Iwata, Charles P. McGraw, Bettye A. Sayle
Abstract This paper describes autoregulation in 14 severe closed head injury patients. It was found to be present in eight of the patients. On the basis of these tests, the authors conclude that the presence or absence of cerebral autoregulation may be of prognostic value, the absence indicating a functional loss of cerebrovascular activity. Their findings also indicate that loss of autoregulation combined with an elevated ICP will probably lead to death. THERE IS A CONTROVERSY on whether cerebral autoregulation is present in head injury patients. We have observed that autoregulation is present immediately following severe head injury in unanesthetized baboons. Many authors believe autoregulation is lost in experimental head injury. It may be that autoregulation is lost during the posttraumatic course with deterioration of cerebral conditions.
1971-02-01
Technical Paper
710872
D. H. Robbins, V. L. Roberts
Abstract This paper describes an injury criteria model implemented in computer language, and a restraint system effectiveness index for evaluating the degree to which the vehicle environment can prevent or reduce occupant injuries. The need for criteria of this type is based on the fact that if the degree of protection offered to a vehicle occupant by a restraint system or a vehicle interior (a function of the distribution and magnitude of the forces transmitted to the occupant) could be expressed in quantitative terms, then, more meaningful comparisons could be made between restraint configurations, and, areas of needed biomechanical research and statistical accident investigations could be more readily identified on the basis of the sensitivity of the results when the injury or effectiveness criteria are applied. The injury criteria model consists of three parts: 1.
1971-02-01
Technical Paper
710871
J. W. Melvin, F. G. Evans
Abstract The mechanics of skull fracture in humans has been investigated by many people for over 90 years. A variety of techniques has been used in past studies. Test specimens have been whole cadavers, cadaver heads, skulls and sections of skulls with material conditions including both fresh and embalmed tissue, both dried and moist. Test techniques have incorporated cadaver drop tests, drop towers, and universal testing machines with the impacting surfaces including large surfaces, both flat and curved, and localized flat and curved surfaces. Some of the studies used impact energy as the measured test parameter, others used impact load and some studies used both quantities to describe the impact. The results of recent studies on the mechanical properties of cranial bone suggest that local values of strain energy density present in the bone of an impacted skull may be the critical parameter in the initiation of skull fracture.
1971-02-01
Technical Paper
710869
R. G. Rieser, J. Chabal, C. W. Lewis
Abstract Headform impacts at 5.5-7.7 mph using the 22 lb air-stabilized missile were run on glass panels that did not fracture to measure deceleration pulses and obtain Severity Index (SI) values. These tests show low SI values for this range of impact velocities. Dummy-windshield tests were run at speeds of 8.7-21.9 mph to measure SI and laceration. In all cases laceration is low and SI values do not indicate concussive hazard below approximately 15 mph impact velocity even when the glass does not fracture. These data are of particular interest for those accident situations below the probable velocity for deployment of a passive restraint such as the air bag. The currently used HPR interlayer for automotive windshields shows excellent safety performance at room temperature but is less effective at other temperatures. Impact studies of several glass structures at 30-110 F are presented for 0.030 and 0.037 in. thickness HPR interlayers.
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