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This paper presents an analysis of the economic feasibility of a demand-responsive transportation system employing driver-operated vehicles on existing street networks. The system is designed to meet the general public transportation needs of a suburban community. The analysis follows traditional economic theory in developing demand and supply curves for the transportation service as a consumer good, followed by an investigation of the equilibrium between demand and supply under various market conditions. Cost models specifically applicable to a transportation service with demand-responsive attributes are formulated to calculate the system supply functions, and an attitudinal survey is employed to generate estimates of demand in the case study community. The demand and supply equilibrium situations are investigated with respect to funding alternatives and sensitivity to changes in supply and demand variables.

The conflicts in the design of turbines for an automotive gas turbine engine are examined. Considerations of stress, efficiency, engine and vehicle acceleration requirements, and compatibility of the flow path are shown to impose a number of opposing requirements. The philosophies used to compromise the conflicts in two successive engine designs are presented. Following a discussion of turbine test facilities, test results are presented for a typical turbine.

As the design of automobiles changed over the past seventy years, manufacturers have increased the usage of decorative trim to further enhance the beauty of styling concepts. As new trim materials were introduced and parts became more complicated in design, producers have continued their efforts to produce decorative trim parts which remain attractive during the service life of the automobile. The service performance of trim materials in several geographic locations, the use of accelerated tests to predict service performance, recent developments in improving the durability of plated parts, and requirements for producing quality exterior decorative trim are reviewed in this paper.

THIS PAPER discusses the Stirling thermal enging from four points of view: 1. The ideal, thermodynamic point of view, showing the inherent potentialities of the ideal Stirling cycle in comparison to the basic cycles of other engines. 2. The physical engine and its method of operation with respect to the ideal cycle and the limitations of practical mechanics. 3. Performance data from the first modern Stirling engines ever operated in the United States, evaluating the relationship between the new engine and other more familiar engines of similar sizes. This comparative discussion serves to demonstrate the advantages and disadvantages of the Stirling engine and to indicate its proper place in the 1960 family of prime movers. 4. A look backward into the century of history behind the modern engine pointing out significant milestones in the engine's development.

Two steam-powered passenger ears have been designed, built, and tested. The SE-101 is an intermediate sport coupe incorporating the comfort and convenience features of a modern passenger car and vehicle performance comparable to a low-powered automobile. The SE-124 is a very low-power intermediate sedan with manual start and semiautomatic control. The characteristics of these cars were evaluated relative to the operational requirements of current transportation needs, with particular emphasis on exhaust emissions. Start-up time, exhaust emissions, fuel economy, acceleration, and water consumption data are presented. Although any one of these characteristics may be improved at the expense of others, it does not appear that any compromise can satisfy all of the areas required by today's motorist.

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.

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.

Utilization of numerically controlled milling has been found particularly attractive in producing, in limited quantities, the three-dimensional curved surfaces characteristic of turbomachinery. In experimental and developmental programs its use can result in decreased fabrication cost, reduced lead time, and improved dimensional accuracy. Following a review of the general classifications of numerically controlled milling machines available for manufacture of such parts, illustrations are given of some of the procedures and techniques employed in their use. A variety of parts made using numerical control serve as examples.

A novel method for the intermittent supercharging of an internal combustion engine in a vehicle is described. During full throttle operation, high pressure motivating air entrains ambient air and compresses it to an intermediate pressure in the diffuser of an air ejector. Flowing through the carburetor and into the engine, the supplemental air augments engine power, reducing vehicle acceleration time by as much as one-third. By allowing engine size to be reduced, better economy without loss of performance is possible. Typical vehicle installations are described and problem areas discussed.

Two Highway Safety Research Institute (HSRI) dummies were tested and evaluated. Based on the analysis given, the HSI dummy should not be used for vehicle qualification testing. However, many of its components offer viable alternatives for future dummy development. The dummy was found to have inadequate biomechanical fidelity in the head, neck, and chest, although its characteristics were very promising and, as a whole, biomechanically superior to the Hybrid II. Its repeatability and reproducibility in dynamic component tests were better than the Hybrid II dummy. In particular, the HSRI friction joints were outstanding in repeatability and had a significant advantage in usability in that they do not require resetting between tests. In three-point harness and ACRS systems tests, the values of injury criteria produced by the HSRI dummy were generally lower than those obtained with the Hybrid II, especially the femur loads in the ACRS tests.

The incentive for use of an interstage diffuser in a free-shaft gas turbine engine is briefly examined and some pertinent published background data reviewed. Tests of two annular diffusers behind an upstream turbine show the deleterious effects of turbine exit flow nonuniformity on diffuser behavior. The flow acceleration provided by the area contraction of a power turbine nozzle located at the diffuser exit substantially improves the nature of the flow previously found to exist at the diffuser exit in the absence of the nozzle.

The following work was done in support of a continuing program to better characterize the behavior of the human chest during blunt sternal impact. Previous work on this problem has focused on determining the force-time, deflection-time, and force-deflection response of embalmed and fresh cadavers to impact by a 15 cm (6 in) diameter striker of variable mass traveling at velocities of 22.5-51 km/h (14-32 mph) and striking the sternum at the level of the fourth intercostal space. Additional questions persist concerning whether the anterior and posterior regions of the chest behave as highly damped masses or oscillate after impact, the relationship between force delivered to the surface of the body and the acceleration of the underlying regions, and the influence of air compressed in the lung on thoracic mechanics.

A professional high diver, instrumented with accelerometers, performed sixteen dives from heights between 27-57 ft. For each dive, he executed a 3/4 turn and landed supine on a 3-ft deep mattress which consisted of pieces of low-density urethane foam encased in a nylon cover. Using FM telemetry, sagittal plane decelerations were recorded for a point either on the sternum or the forehead. Impact velocities and corresponding stopping distances for the thorax and the head were calculated from high-speed movies of the dives. For a 57-ft dive, the impact velocity of the thorax was 41 mph with a corresponding stopping distance of 34.6 in. The peak resultant deceleration of the thorax was 49.2 g with a pulse duration of 100 ms. The maximum rate of change of the deceleration of the thorax was 5900 g/s. No discomfort was experienced as a result of this impact. The maximum forehead deceleration occurred during a 47.0-ft drop and exceeded 56 g with a Gadd Severity Index greater than 465.

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.

This paper describes the usage of an exponential weighting factor for appraising deceleration or force impulses registered on dummies or impacting hammers in safety testing. The proposed impulse-integration procedure, it is shown, takes into account in a more rational way, and in better conformity with published injury tolerance data, the relative importance of time and intensity of the pulse than do the “peak g” or impulse-area criteria. Use of the new Severity Index for assessment of head impact pulses is illustrated. It is shown to be of special value in comparing the relative severity of pulses which differ markedly in shape (because of structural differences in the component being struck) and it is pointed out that without a weighting factor of this nature, laboratory impact tests can yield incorrect ranking of the relative safety merit of alternative designs. Automated methods for quick calculation of the Severity Index are possible.

Interactive graphics is an aid which eliminates the data management problems that arise when manually preparing finite element models. Line and surface data representations of sheet metal automotive stampings are displayed on a cathode ray tube (CRT), and these data are then used for building finite element models. Elements are built by creating node points with the light pen or by using automatic mesh generating techniques. By using the interactive capability, the user immediately sees the results of his modeling decisions and can make changes in his model as a result of viewing his work. The interactive graphics system allows the user to define his elements, load cases, boundary conditions, and freedom sets without worrying about the grid point or element numbers. All information is communicated through the use of either the light pen or the keyboard. As information is supplied about the model, it is stored in a data base for review and possible change.