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1976-02-01
Technical Paper
760014
Francis A. DiLorenzo
This paper attempts to establish a correlation between bodily injury and the rate at which energy (power) is transferred to the body. Two head impacts are analyzed to demonstrate the procedures, however, analysis results are given for eleven head impacts. The methods involve the fundamental laws of mechanics and only the power levels are established empirically. Equations are developed that relate power to the absolute values of acceleration and the product of momentum and jerk. From the derived mathematical expressions a procedure for analyzing experimental data is given. The appendix contains a computer program for performing the analysis. Lastly arguments are given that predict the ideal processes for changing energy levels. Although the procedures described in this paper address only the human tolerances, it is conceivable the same procedure may be useful for analysis of inorganic structures.
1976-02-01
Technical Paper
760013
Stanley H. Backaitis, Edwin M. Trout, Randolph J. Wolf
A solid state, low power, self-contained digital crash recorder was developed and installed in the Part 572 crash test dummy for capturing and storing the crash severity-time event. The crash recorder is capable of recording upon internal triggering command the dummy's response in 10 separate data channels. The recorder's performance was evaluated in laboratory and vehicle tests consisting of simulated and real rigid barrier collisions in the forward impact mode and moving barrier collisions in side impacts. The recorder was found to be suitable for capturing and storing high quality crash data compatible with currently used hardwire data acquisition techniques.
1976-02-01
Technical Paper
760824
Max Bender, John W. Melvin, Richard L. Stalnaker
Abstract A versatile high-speed cineradiographic system developed in the Biomechanics Department of The University of Michigan's Highway Safety Research Institute has recently been completed, for application to human injury and tolerance and occupant protection research. This system consists of a high-speed motion picture camera which views a 2-inch diameter output phosphor of a high gain 4-stage, magnetically focussed image intensifier tube, gated on and off synchronously with shutter pulses from the motion picture camera. A fast lens optically couples the input photocathode of the image intensifier tube to x-ray images produced on a fluorescent screen by a d-c x-ray generator.
1976-02-01
Technical Paper
760825
Alan M. Nahum, Randall W. Smith
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.
1976-02-01
Technical Paper
760776
Raymond R. McHenry
Correlation of injury with the nature and severity of the acceleration exposure in actual highway accidents is complicated by problems with uniformity in the interpretation of accident evidence. The SMAC and CRASH computer programs have been developed with the objective of providing aids for interpretation of physical evidence. Through the use of such aids in accident studies, it is possible to establish injury thresholds and mechanisms for living humans in relatively detailed exposures and under different conditions of restraint and protection. In addition to providing refined measures of the performance of protective devices, such studies can provide an improved basis for evaluation of test devices (i.e., anthropomorphic dummies and other surrogate crash victims). The existing forms and the evidence requirements of the SMAC and CRASH programs are described and results of pilot application studies are presented and discussed.
1976-02-01
Technical Paper
760774
Georg D. Frisch, Joseph O'Rourke, Louis D'Aulerio
This paper analyzes data on the dynamic response of the living human head and neck to -Gx impact acceleration. The Calspan “3D Computer Simulator of a Motor Vehicle Crash Victim,” Ultrasystems “Crash Victim Simulator - Light Aircraft” and Boeing Computer Services “Prometheus” were used to provide estimates of the responses monitored. Inputs to the programs were made as comparable as program restrictions would allow. Outputs were compared to each other as well as to the corresponding human test run. Program outputs proved to be consistent but failed to adequately replicate human results. Inclusion of head to neck articulation did not by itself improve results. Relocation of the head pivot away from the occipital condyles or introduction of muscular activity was indicated.
1976-02-01
Technical Paper
760775
Peter Niederer, Felix Walz
Computerized simulations of traffic accidents are done for research and for reconstruction purposes. Motions of several interacting bodies, however, are prone to be highly instable. Meaningless results can therefore be produced. Two methods are introduced which allow for an assessment of the stability of a motion. The results obtained seem to support the hypothesis that all accident motions are instable to some degree. In each accident situation to be simulated or reconstructed on a computer it has therefore to be decided whether the appearing instabilities are tolerable or not. Two field examples are shown which exhibit tolerable and intolerable instabilities.
1976-02-01
Technical Paper
760793
Hermann Danckert
DEVELOPMENT OF CRASH ENERGY MANAGEMENT SOLUTIONS The mechanical properties of to day's vehicle are investigated as a basis for favorable crash energy management solutions. Important parameters follow the similarity law of Cauchy. Different concepts of intervehicular compatibility are discussed. The tolerable closing speeds depending on the mass ratio and accelerations of colliding vehicles are calculated using realistic data of deformation forces, human load tolerances and different restraint system characteristics. Engine effects and measures to reduce engine aggressivness are investigated. Possible solutions for accident types other than frontal collisions are briefly discussed.
1976-02-01
Technical Paper
760801
William H. Muzzy, Leonard Lustick
Abstract Significant kinematic parameters of the head are compared between a Hybrid II head and neck (per Parr 572, Federal Motor Vehicle Safely Standard 208) and human volunteers subjected to the same -Gx sled acceleration profiles. Comparison time profiles between the dummy and human subjects for component's of linear acceleration, velocity, and displacement of the head center of gravity and the first thoracic vertebral body (T1) anatomical origin, as well as components of angular acceleration, velocity, and displacement of the anatomical coordinate systems are presented for 6, 10, and 15G peak sled acceleration in the -Gx environment. Significant differences between the dummy and human volunteers are discussed in regard to peak values of parameters, time latencies, and overall shape agreement in a time window where motion is significant.
1976-02-01
Technical Paper
760797
Ulrich Seiffert, Ruediger Weissner
Rigid moving barriers and deformable moving barriers are compared conceptually and analytically, and advantages of the deformable barrier in representing average vehicles are presented. Several physical concepts for controlled energy dissipation are described, and experimental test results given. Architecture and powerplant mass representation are discussed, and the need for field accident analysis as a basis for structural representations is stressed.
1976-02-01
Technical Paper
760804
Ulrich W. Seiffert, Heinz E. Leyer
Abstract Dummy component calibration tests were performed as specified in 49-Part 572 with temperature as the independent variable. Well-defined, significant dependencies of results on temperature were recorded. Total system sled tests were then run with the assembled dummy at different temperatures. Differences were found both in injury-related data and in the type of kinematic motion during impact.
1976-02-01
Technical Paper
760805
Kenneth J. Saczalski, John D. States, Ivan J. Wagar, Edward Q. Richardson
The basic physical mechanisms underlying recent experimentally observed anomalous behavior in the impact performance of safety helmets evaluated with soft (human-like) and hard (magnesium alloy) headform surrogates are qualitatively and quantitatively explained in this paper. The principal and physical mechanisms brought to light in the headform surrogate investigation are directly applicable to the utilization of other forms of surrogates (head -neck, thorax, whole body). In particular the results raise a serious question as to the validity of using non-human responding surrogates, with human generated injury tolerance data, for the purpose of assessing safety system performance. The implications of the results are that good crash-impact protective devices (helmets, restraints, etc.) could be penalized and, equally important, less safe crash-impact protective system designs could result from improper assessment of safety system performance.
1976-02-01
Technical Paper
760802
J. Harris
Abstract The lack of a suitable means of measuring levels of protection for car occupants in side impacts has hampered development of satisfactory designs of car to withstand impacts of this type by cars or other objects. The TRRL side impact dummy described in the paper has been designed specifically for this task and its use has been demonstrated in achieving a high level of protection for occupants of the Leyland Marina cars developed in the international car safety programme. The dummy makes possible the matching of each part of the energy absorbing inner face of the donor structure to the different loadings on the human frame, which can be safely tolerated at the shoulder, chest and pelvic regions.
1976-02-01
Technical Paper
760809
D. Orne, E. Barak, R. F. Fisch
Abstract A contoured rear-facing restraint couch has been designed, fabricated and tested which protects wheelchair-confined passengers in simulated frontal barrier collisions at velocities of up to at least 25 mph and in simulated rear-end collisions. A cable system secures the wheelchair to the base of the restraint couch and is automatically engaged when the wheelchair is backed against the couch. A three-point belt system secures the passenger in rear-end collisions or during elastic rebound in frontal collisions. Plastic deformation of the couch framework limits g-loadings on passenger and couch even during severe impacts.
1976-02-01
Technical Paper
760808
L. M. Patrick, W. D. Wickersham
Abstract Children riding on the bed over the cab in campers can be injured in forward force collisions from striking the glazing material and/or being ejected through the opening. The two types of glazing commonly used are acrylic and laminated. A comparison of the performance of the two types of glazing in simulated forward force collisions at velocities up to 30 mph showed the acrylic material to pose threats of neck and back injury and the laminated material to result in lacerations. Ejections occurred with the acrylic that were not present with the laminated windshields when correct glazing techniques were used. With poor installation procedures, ejections occurred in both types of glazing materials. It is concluded that the best way to avoid injury is to prevent the child from riding in the over-the-cab bunk. If the child does ride there, his body axis should be positioned at an angle to the longitudinal axis of the vehicle.
1976-02-01
Technical Paper
760807
L. M. Patrick, C. C. Chou
Abstract An improved windshield with a special, thin, plastic inner surface attached to the inner surface of a three layer windshield similar to those used in the United States minimizes lacerations from occupant impact to the windshield during a collision. The plastic coats the sharp edges of the broken glass preventing or minimizing laceration. It was evaluated by comparing its laceration performance with that of a standard windshield in simulated barrier crashes at velocities up to 65 km/h. No lacerations resulted from impact to the Securiflex windshield at Barrier Equivalent Velocities up to 65 km/h. Substantial laceration resulted at velocities above 20 km/h with the standard windshield. It is concluded that the Securiflex windshield essentially eliminates lacerations in the particular vehicle involved at velocities up to at least 65 km/h.
1976-02-01
Technical Paper
760813
K. W. Krieger, A. J. Padgaonkar, A. I. King
A series of 10 full-scale experimental simulations of pedestrian-vehicle impact was carried out using cadavers and a 95th percentile anthropomorphic dummy. The test subjects were impacted laterally and frontally at 24, 32 and 40 km/h (15, 20 and 24 mph). Each subject was extensively instrumented with miniature accelerometers, up to a maximum of 53 transducers. The nine-accelerometer scheme was used to measure angular acceleration of body segments from which it was possible to compute the head injury criterion (HIC) for cadaver head impact. A full-size Chevrolet was used as the impacting vehicle. The impact event was three-dimensional in nature during which the body segments executed complex motions. Dummy impacts were more repeatable than cadaver impacts but the response of these test subjects were quite different. The HIC was higher for head-hood impact than for head-ground impact in two of the cases analyzed.
1976-02-01
Technical Paper
760817
Charles K. Kroell, Dennis C. Schneider, Alan M. Nahum
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.
1976-02-01
Technical Paper
760819
N. S. Hakim, A. I. King
Previous work on biodynamic response to whole-body +Gz (caudocephalad) acceleration gave ample evidence of facet loads in intact cadaveric spines. The computation of facet loads was based on an assumption that the total spine load was proportional to the measured seat pan load. In this study, the aim is to investigate the magnitude of the facet load during static and dynamic loading of an exised spinal segment. The applied loads resulted in a close simulation of those experienced by the intervertebral disc during whole-body impacts. An intervertebral load cell was used as the controlling mechanism in the duplication of the whole-body run in a testing machine. During these tests, both the total spine load and the intervertebral load were measured and thus the facet load was determined without relying on any assumptions.
1976-02-01
Technical Paper
760620
Allen Coombs, William Lippert, Larry Lowden, David Michaels, Charles J. Owen, Tom Thomas
On January 10th, 1972, an S. A. E. Paper “Lighting System Performance and the Computer as a Maintenance Tool” (720087) was presented by Charles J. Owen. This was a paper presented on the causes, effects, corrections and a study in good and bad electrical wiring, presented pictorially as well as editorially. We recommend that paper to you for reading. On November 4th, 1974, S. A. E. Paper “A Case for Standardization” (741143) was presented by Charles J. Owen. The purpose of this paper was intent on “improving the breed”. The recommendations and specifications were very specific. In view of the two previous papers, this paper is presented specifically for the designer with back-up data involving recommendations that the industry have generally accepted as applied to the electrical wiring systems The practical data included, is a first in relating indexes of performance and indexes to cost comparisons. The usefulness of this paper in aiding a Designer is the target of the authors.
1976-02-01
Technical Paper
760769
Jeffrey C. Huston, Sunder H. Advani
A comprehensive three dimensional model of the human head and neck is formulated. This model predicts the center of mass displacements, velocities, and accelerations of the head and neck resulting from contact and/or inertial impact forces. Key anatomical components are incorporated in this model along with a joint stopping mechanism. Known acceleration profiles are inputed to the torso and/or head force time histories are specified. The equations of motion are then derived using d'Alembert's form of Lagrange's Principle and are numerically integrated using a fourth order Runge-Kutta technique. Validation is accomplished by the comparison of responses from (i) direct frontal and occipital impact experiments on human cadavers, and (ii) sled tests conducted on human volunteers.
1976-02-01
Technical Paper
760771
S. A. Tennyson, A. I. King
A biodynamic model of the spine simulated the action of spinal musculature on the head, vertebral bodies and pelvis in the midsagittal plane. Muscle was treated as a force generator whose contractile force was dependant on muscle stretch, stretch rate and neural delay time. Eight model runs were conducted with and without muscle, simulating +Gz and -Gx impact acceleration. The model predicted that spinal musculature was incapable of affecting overall spinal column kinematics. However, as a result of muscle contraction, significantly higher local axial forces were predicted in the discs and facets than were predicted when muscle was absent.
1976-02-01
Technical Paper
760770
U. R. Pontius, Y. K. Liu
A computer model of the neuromusculature and passive elements of the cervical spine during whiplash is presented. The model indicates that the neuromusculature increases the rotational stability of the cervical spine during low level accelerations. This results in decreased bending but increased axial compressive stresses in the passive structures and increased axial tensile stresses in the neuromusculature. Increased neural feedback augments peak acceleration and stress because the “active” neuromusculature causes a flexion response near the end of the acceleration pulse. A decrease in neural delay time allows the muscles to act earlier and decrease peak accelerations and bending stresses.
1976-02-01
Technical Paper
760772
Joseph C. Free, James W. Hall, Cesar A. Montano
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1976-02-01
Technical Paper
760773
David C. Viano, Tawfik B. Khalil
The mechanical response of a plane strain finite element model depicting an axial midsection of a human femur is investigated for both static and dynamic condylar loadings. An elastic bi-medium structure composed of compact and cancellous bone is used to represent the femur. Critically stressed locations are identified and associated static and dynamic load levels which may initiate femur fracture are calculated. The predicted fracture sites and load levels are found to be in good agreement with published data for cadaver knee impacts. An important conclusion of this investigation is that the peak stress or strain and therefore femoral tolerance significantly depends on the impact duration due to stimulation of structural resonances.
1976-02-01
Technical Paper
760527
H. W. Carhart, I. Pinkel, J. H. Warren
At the request of the FAA the CRC initiated a study to investigate the effect of fuel volatility on aircraft fire safety. The primary objective was to use new data which have become available over the last ten years to revise and update the 1964 CRC Report on Aviation Fuel Safety. The huge increase in jet aircraft utilization provided a data base for a statistical analysis of accidents; and new data on non-equilibrium conditions involving fuel-air mixtures and fuel electrification facilitated a more complete laboratory study. The results of these two studies were then used to prepare the final report which is summarized in this paper.
1976-02-01
Technical Paper
760486
James Shaw
This paper is submitted to insure that every basic precaution is taken in the design of the installation for an aircraft filler cap and adapter for lightning protection. The axiom in the industry of installing a lightning proof cap solves the problem of a lightning safe installation. However, designers sometimes disregard the problem of the installation of the adapter and the adapters mating parts. Adherence to the FAA and military specifications are considered acceptable while these specifications contain only the bare minimal requirements. This design criteria of only using a lightning safety cap and disregarding the installation of the adapter sometimes leads to an expensive redesign or retrofit of the aircraft after the plane is in production.
1976-02-01
Technical Paper
760500
Robert H. Stanton
The FAA is involved in aircraft design for safety and continued airworthiness, its certification functions consisting of making preoperational findings or determinations that a product design, a facility, an operation, or a person satisfies the applicable Federal Aviation Regulation. This paper, in discussing safety systems, places particular emphasis on the design of aeronautical hardware for regulatory compliance.
1976-02-01
Technical Paper
760494
D. C. Johnston
Civil litigation arising out of claims of defect in design and/or manufacture causing injury has now expanded into a new arena giving rise to claims of defect in design and/or manufacture, increasing the injuries complained of, although not causally related. This new doctrine of “CRASHWORTHINESS” or “second injury” evolved first out of automobile accidents, but in the last few years, has been extended to aircraft. Recent Court decisions have indicated a trend toward the adoption of this new doctrine by a majority of the Courts in this Country. This trend will obviously affect the future planning of aircraft manufacturers and engineers who are responsible for programs of research, development and production changes in the field of crashworthy design. Secondly, this paper discusses the possible personal liability exposure of the engineer and the method and means by which the engineer may protect himself.
1976-02-01
Technical Paper
760480
Brent W. Silver
This paper represents the results of a computer study of General Aviation accidents, particularly stall and spin accidents. In an introductory review, five transportation modes are compared on the basis of deaths per 100,000,000 passenger-miles. Of these, General Aviation has the highest accident rate, and domestic airlines the lowest. Descriptions of four “stall-related” accident types (stall, spin, spiral and mush) are given. A summary for these four accident types over the years 1965 through 1973 is given for both twin- and single-engine aircraft. The patterns are found to be similar. Stall/spin accident patterns are reviewed for a group of 31 single-engine aircraft (1965-1973) by: kind of flying, phase of flight, turning flight, airport proximity, weather, daylight, pilot experience and age, stall warning indicator, and cause of accident. Individual results are presented for the 31 aircraft by make and model.
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