Search Results

Data on towaway accidents involving 1973- and 1974-model American passenger cars were collected according to a systematic sampling plan in order to measure 1974 restraint system performance. The data on 5,138 drivers and right front passengers were collected by three organizations: Calspan Corporation, Highway Safety Research Institute, and Southwest Research Institute. Analysis of the data showed that the 1974 ignition interlock system increased full restraint system usage by a factor of 10 over 1973 cars. The 1974 full restraint system (lap and upper-torso belts) also demonstrated a greater reduction in severe injuries (AIS≥2) than the 1973 lap-belt-only system. Paradoxically, little reduction in 1974-model severe injuries was found when the two model years were compared, although no attempt was made to control for confounding factors in the accident cases.

Injuries produced by standard three point restraint systems with retractors will be compared between cadavers in laboratory simulated collisions at 30 mph barrier equivalent speed and lap and shoulder belted front seat occupants in real world frontal collisions of '73-'75 full sized cars. Tests conducted at SwRI with belted, unembalmed, fresh cadavers have resulted in extremely severe thoracic and cervical injuries, including multiple rib fractures, fractures of the sternum, clavicle and cervical vertebrae. On the other hand, injury data from a national accident investigation study to evaluate the effectiveness of restraints in late model passenger cars indicates that such injuries in real world crashes of equivalent severity are not always observed. The reasons possible for these differences are discussed. Both programs at SwRI are funded by the National Highway Traffic Safety Administration.

Unembalmed cadavers restrained with a three point harness were exposed to a deceleration environment of 20, 30 and 40 mph BEV.* Injuries were tabulated from detailed autopsies. The results Indicate an AIS-1 injury at 25.5 mph, an AIS-2 injury at 31.5 mph and an AIS-3 injury at 34.5 mph. The AIS-3 injury level is recommended as the maximum acceptable injury. The cadavers sustained the same types of injury that have been reported in medical literature including bruises, abrasions, lacerations, fractures and viscera ruptures, but injury severities were greater in the cadavers than in living humans at a given collision severity. Also, there is a wide spread in the degree of injury between cadavers due to differences in age and physical condition. The threshold of cadaver rib fracture is 30 mph and the threshold of cadaver vertebral fracture is between 30 and 40 mph for the environment utilized. More numerous and severe abdominal injuries were observed.

The purpose of this paper is the comparison of the protection efficiency between three-point belt and air bag systems under various crash conditions. Dynamic tests have been performed with subcompact vehicles (Renault R 12) in which two dummies were restrained, either by three-point belts with load limiting devices, or by air bags consisting of solid gas generators and bags including porous outlets (the driver's knees were protected by a collapsable structure). Three types of crashes were chosen: frontal barrier crash at 50 km/h (13,9 m/s) head-on crash between two vehicles with overlap at 50 km/h (13,9 m/s) crash against a guardrail at 80 km/h (22 m/s) with 30° angle of incidence. The comparison drawn from commonly used biomechanical indices shows that the three-point belt ensures a protection in each analysed crash type but it should be improved in order to reduce head deceleration.

Occupant response to side-impact collisions is studied with a mathematical vehicle/occupant model, the MVMA Two-Dimensional Crash Victim Simulator. A primary goal is the investigation of head-torso relative motion and neck forces and moments. Computer simulations were performed in conjunction with a study on properties of the neck in lateral motion (not reported on here) involving 96 subjects. The subject pool consisted of six carefully defined population segments which represented young, middle-age, and elderly male and female adults of average stature. The side-impact simulations make use of much pertinent data resulting from the volunteer subject testing program, including head-neck lateral bend range of motion, sternomastoid muscle group strength, reflex time, and anthropometry.

This paper describes the injury relations which result when car-to-car crashes are analyzed using a computerized accident reconstruction procedure. The results of the study are presented in the form of graphical relations between injury severity and crash severity. Effects of factors such as impact location, seating position and vehicle weights are discussed. THIS PAPER EXPLORES the use of a relatively new tool for accident reconstruction - Simulation Model of Automobile Collisions (SMAC). The capability of this program to simulate a wide variety of crashes is described in detail elsewhere (1,2,3)*. This study is limited to the reconstruction of side impact collisions in which two passenger vehicles are involved. The need for redesigning vehicles based on an understanding of this crash condition is amply demonstrated by the fact that 28 percent of passenger car occupant fatalities and 41 percent of passenger car occupant injuries are caused by side impacts (4).

Currently used criteria based on functions of spinal acceleration obtained from crash test dummies are shown to be invalid indicators of chest injuries in blunt frontal impacts. Cadaver impact data are analyzed; and injury is found to be a statistically significant function of chest deflection, chest depth, and cadaver age at death. Based on the resulting regression equations, injury-limiting chest deflections are recommended for various size test dummies. The recommendations apply only to test dummies that have significant thoracic biofidelity for blunt frontal impact. They are valid for environments which include signigicant blunt frontal impact. Their extension to other environments has not been validated.

Tests were conducted to provide information on the mechanics of child restraint with a five-point harness system. For anatomical reasons, the juvenile chimpanzee was chosen as the best approximation to the human child. Sedated juvenile male chimpanzees withstood frontal deceleration tests in a five-point harness at crash speeds of 32.2, 40.2, and 48.3 km/h (20, 25, and 30 mph) without skeletal bone fractures or evidence of soft tissue injury. Injury assessment was by X-ray and blood serum enzyme analysis as well as ECG readings and post-test observations of the animals' behavior. While this animal model does not fully guarantee the identical performance of a five-point harness system with humans, these results support the opinion that the protection offered a child occupant in a five-point system is comparable to that available to adult passengers in conventional automotive restraint systems.

Our tests with fresh human cadavers were continued (cf. proceedings, 18th Stapp Car Crash Conference). Presented herewith are the results of 103 tests evaluated so far. While the severity of injuries showed an increase with advancing age, it is not obviously dependent upon weight or sex. Under the conditions chosen by us, the 12 to 30-year age group reached the thorax tolerance level at an impact velocity of still below 50 km/h with a stopping distance of 40 cm, the 30 to 50-year age group of below 40 km/h, and the age group beyond 50 years below 30 km/h. A comparison of our results with volunteer tests (Ewing et al., 29) and with evaluated real accidents (Patrick et al., 22) as well as with similar cadaver tests (Tarriere et al., 19) is made. When introducing safety testing regulations for vehicles in the light of dummy tests, the broad spectrum of the respective age groups has to be considered. The thorax injuries may be slightly mitigated due to a lessening of the surface pressure.

Sternal and/or spinal acceleration data from eighteen of the unembalmed cadaver, blunt thoracic impact experiments reported by the authors at the Eighteenth Stapp Conference have been analyzed and several related response parameters computed. High acceleration levels, rates of onset, and Gadd Severity Indices were found in sternal acceleration measurements, whereas quite low values were obtained from the spinal regions in the same tests. A Severity Index value of 1000, computed from a sternal acceleration measurement, would be associated with only a mild exposure; whereas for a spinal measurement, the same value would reflect an extremely severe exposure. Correlation matrices which include cadaver characteristics, input and response parameters, and Abbreviated Injury Scale ratings show that none of the sternal acceleration parameters correlate well with AIS rating in the analyzed data base.

The results of a design study of the application of a simplified aircraft fuel control method to automotive gas turbines is presented. Although the requirements for control of automotive gas turbines impose a degree of complexity exceeding that of fixed geometry aircraft engines, the hydromechanical computing circuit employed in the earlier application is found to be applicable to the automotive requirements. Methods for compensation and/or adjustment for wide range fuel density and inlet temperature variations and for obtaining turbine vane actuation, acceleration optimization, and turbine braking are presented.

The purpose of this paper is to describe the development of the 43027 electronic fuel control system, which is designed to service a wide variety of industrial gas turbine users. It also discusses applications of the fuel system.

The evolution of multiple shaker induction of pure modes has nonetheless retained a key assumption and consequent test procedure a quarter of a century old -- mode vectors are real, i.e., in phase except for polarity and therefore an in phase force vector should be applied at a single frequency along the jω axis. The validity of the assumption and procedure is limited to undamped or proportionally damped structures. Modern, complex and inhomogeneous hardware seems less likely to satisfy the limiting assumption. The complex modes of non-proportionally damped structures can be induced with two improvements on existing procedure made possible by modern electronics and digital computers -- apply a force vector controlling AMPLITUDE and PHASE and allow COMPLEX FREQUENCY EXCITATION anywhere in the s plane.

In recent years, the development of digital signal processing hardware and software has progressed to the point where frequency response functions can be measured in a fraction of the time required by previous measurement techniques. This has caused a renewed interest in convenient and reliable software for effective modal survey work via frequency response functions to manipulate, store, retrieve and display frequency response functions, perform on-line modal parameter estimation, display resulting mode shapes and check the accuracy of the results. This paper reviews the relationship between frequency response functions and modal parameters and presents the software architecture used by the authors for effective use of frequency response functions in a modal survey activity.

In early 1975, a Hughes-built communications satellite was subjected to a ground vibration survey test to determine resonant frequencies, modes, and damping characteristics. Two different techniques were independently utilized to define the space vehicle vibration modal parameters. One consisted of the classical technique where multiple shakers were used to tune in a single resonance to define its frequency and normal mode shape. The second approach utilized recent technology and a data processing technique which provides for more complete data acquisition in a shorter actual on-the-floor test time. The latter method uses a single point random excitation to provide all the data required, which then undergoes a considerable amount of data processing. Transfer functions are computed for each accelerometer location from which the modal properties are assembled. The subject paper describes the two test techniques, data reduction, processing required, and a comparison of results.

This paper describes the analysis, design and development of compliant-mounted gas lubricated journal and thrust bearings for supporting a 12 lb, 93,500 rpm, turboalternator rotor. Component testing of the bearings demonstrated excellent load capacity and start-stop capability. It was found that lift off could be achieved at low speed (400 rpm) and under high unit loads (7 psi). Simulator tests were accomplished to speeds of 60,000 rpm. Full speed testing was aborted by a journal bearing failure, due to a blockage of cooling-air flow.

A review is presented of the features which make the resilient foil air bearing attractive in high temperature and high-speed turbomachinery. Turbomachinery requirements are considered with emphasis on automotive gas turbines in which sometimes both air and oil lubricated rotor bearings are used. Techniques used in designing and matching foil bearings to the gas turbine and economically developing them under simulated operating conditions are discussed together with some developmental experiences. The construction of foil bearings, their materials and coatings, manufacture and accuracy is reviewed. A look is taken at the future challenges of anticipated higher cycle temperatures and speeds where 1400°F bearing soakback temperatures may exist and the all foil bearing rotor system will be required. The possibility of ceramic foil bearings is considered and an example of some new technology work is used to illustrate the continuing development work which will be required.

Active Control Technology concepts hold considerable promise of improved efficiency for commercial transports. The aplication of these control concepts to current transport airplanes has typically been non-design impacting - that is, the design proceeded in a conventional manner. Realization of the potential of ACT will require a departure from this design procedure, requiring new approaches to the airplane design process. The paper briefly describes ACT and reviews existing transport airplane configurations to point out that ACT is not particularly new or novel. Following an examination of where the payoffs are for a new airplane - considering the sensitivity to design speed, range, configuration, and size - the risks associated with ACT implementation are reviewed. The impact of ACT on the transport airplane design cycle is discussed to illustrate the challenges that lie ahead.

The specifications of design requirements for Active Control Technology (ACT) flight control systems are addressed based on current state-of-the-art trends with emphasis placed on the impact of specific requirements on system mechanization. Of particular interest is the sensitivity of the ACT system design to redundancy managment, reliability and maintainability requirements, and to the related subsystem interface concepts. Experience on both military and commercial aircraft programs is cited to provide insight to establishment of practical design requirements for ACT systems.

The current achievements of Concorde and its powerplant are summarised, and the route by which technology may be evolved for making further SST performance and environmental advances appropriate to a second generation aircraft is indicated. Experimental data on takeoff noise is discussed. Future improvements in turbine cooling technology applied to a turbofan of around 1.7 bypass ratio, together with possible future improvements in aircraft L/D and structure weight, should permit the development of an SST with substantial increases in payload percentage and range relative to Concorde while meeting current FAR Part 36 noise limits without a suppression system. The engine could be derived from the current Olympus 593 Mk 610.