Criteria

Text:
Display:

Results

Viewing 164191 to 164220 of 188284
1972-02-01
Technical Paper
720958
John W. Melvin, James H. McElhaney, Verne L. Roberts
Abstract This paper describes the development of an improved neck simulation that can be adapted to current anthropometric dummies. The primary goal of the neck design is to provide a reasonable simulation of human motion during impact while maintaining a simple, rugged structure. A synthesis of the current literature on cervical spine mechanics was incorporated with the results of x-ray studies of cervical spine mobility in human volunteers and with the analysis of head-neck motions in human volunteer sled tests to provide a background for the design and evaluation of neck models. Development tests on neck simulations were carried out using a small impact sled. Tests on the final prototype simulation were also performed with a dummy on a large impact sled. Both accelerometers and high-speed movies were used for performance evaluation.
1972-02-01
Technical Paper
720957
B. M. Bowman, D. H. Robbins
Abstract A parameter study is performed involving several analytical vehicle occupant models in current use, with investigation of neck representations a primary goal. Side, oblique, and rear impact situations are investigated. Attention is given to the effects of varying head-neck mass and moments of inertia, anthropometry, muscle strength, and location, as well as well as strength, of motion-limiting “stops.” A model that replaces the conventional simple ball-joint neck with a two-joint, extensible neck is studied. This model also makes use of joint-stop ellipses to approximate the anatomical range for relatively free angular motion at a joint. Allowance is made for the effect of muscle contraction on occupant dynamics as a function of the degree of voluntary or involuntary tightening of the muscles, based upon experimental findings. A discrete parameter neck model that treats the cervical spine as a linkage of rigid vertebrae and massless, deformable discs is discussed briefly.
1972-02-01
Technical Paper
720932
P. J. Clarke
For many years, the primary consideration for determining motor gasoline volatility specifications has been good car performance, i.e., fast start-ups, freedom from vapor lock, and good driveability. Now, for late-model cars, there is a new consideration for volatility control. This is exhaust emissions. Fuel volatility has been found to have a significant effect on the exhaust emissions of many late-model vehicles. A decrease of 5 psi RVP from current levels increased exhaust CO an average of 28% at 70°F and 22% at 30°F in a group of eleven cars. Exhaust hydrocarbons were increased an average of about 5% at both temperatures. Now, before lowering fuel volatility, it is important to consider the effect the change will have on exhaust emissions as well as car performance.
1972-02-01
Technical Paper
720934
Russell F. Stebar, Robert L. Everett
Quick-release chokes may become an essential feature of advanced exhaust emission control systems to minimize emissions during warmup. However, quick-release chokes greatly impair warmup driveability when gasolines of conventional volatility are used. Consequently, modifications of gasoline volatility were investigated as one approach to restoring warmup driveability with quick-release chokes. Warmup driveability of two test cars equipped with quick-release chokes was measured on a chassis dynamometer at 40 and 68 F using fuels with widely different volatility characteristics. Warmup driveability was essentially restored by increasing fuel volatility in the 40-90% ASTM distillation range. Front-end volatility up to the 40% point had very little effect.
1972-02-01
Technical Paper
720935
William D. Bond
This report presents some design parameters and development experience on quick-heat intake manifolds for evaporating the fuel. These can achieve good fuel evaporation soon after a cold start. Used in conjunction with a fast-opening choke, such a quick-heat intake manifold helps reduce carbon monoxide (CO) emissions. This is especially effective on cars with catalytic converters, since CO caused by cold enrichment is produced at a time when the catalyst is not yet hot and effective. The sensitivity of one design of quick-heat intake manifold to fuel volatility characteristics is included. A variety of ways to correlate drivability with the ASTM distillation characteristics of the fuel are evaluated.
1972-02-01
Technical Paper
720938
Jose L. Bascunana, Milton J. Webb
A program was undertaken to determine which retrofit methods are currently feasible for used cars, considering emission reduction effectiveness, cost, effects on vehicle performance, facilities, and labor skill required for retrofit installation, maintenance, and inspection. An extensive search was made for all sources of information on retrofit methods, developers, and producers. Eleven representative retrofit devices were actually tested in this project. A fleet of 20 used vehicles without factory installed exhaust control systems was used for testing the performance of the retrofit devices. The vehicles were tested first without a retrofit device to obtain a reference baseline, and then with retrofit device installed. Emission tests were conducted by the 1972 CVS Federal Test Procedure. Fuel consumption was also measured during the CVS test. Drivability tests were conducted by an Automobile Manufacturers Association procedure.
1972-02-01
Technical Paper
720939
J. T. Wentworth
Three investigations are reported which clarify the mechanism of exhaust hydrocarbon (HC) emission and suggest new ways to reduce these emissions from reciprocating, 4-stroke, spark-ignition engines. The work was carried out on an engine using the sealed ring-orifice (SR-O) piston, which effectively eliminates exhaust HC emission caused by the piston-bore-ring crevice. This reduces HC emission substantially, making other effects more apparent. In the first investigation, exhaust HC concentrations were unchanged when the engine was run first with oil and then water in the crankcase. This means that oil did not contribute to exhaust HC emission in the SR-O engine. In the second investigation, small patches of simulated deposit attached at different locations in the combustion chamber caused exhaust HC concentration increases which varied by a factor of 10, depending on deposit location.
1972-02-01
Technical Paper
720940
Daniel L. Frank
This paper describes the exhaust emission performance of 127 General Motors automobiles during their first year of operation. All were 1971 models in private service. The evaluation covered the period from November 1970 to November 1971. Each car selected for the program had received an exhaust emission test before leaving its respective assembly plant. At approximately three-month intervals each car was again evaluated for emissions. It was checked for drivability and for conformance to certain emission-related specifications. Emission-related parameters were maintained at the manufacturer's specification. The diagnosis and maintenance performed kept the emission levels near their “end-of-line” averages throughout the length of the program. The causes of the emission failures were determined to define design requirements of future emission systems.
1972-02-01
Technical Paper
720968
K. Langwieder
Abstract In order to contribute to the improvement of traffic safety, the German Motor Traffic Insurers investigated 100,000 accidents in 1969. In dependency upon crash conditions, injuries were related to clearly described car models. The method used is commented upon in detail. This paper deals with the representative material on 10,271 car crashes with passenger injuries. It is shown what types of impact are found in real-life collisions and at what speeds they occur. Facts influencing accident severity are discussed. It turned out that car crashes occur mostly at a collision speed below 60 km/h. Frequently, serious injuries are sustained in cases with moderately severe car damage. This fact is proved by fractures of the skull base, of the cervical spine, of the sternum, of the pelvis, and of the lower extremities, as well as eye injuries. An important percentage of casualties occur in average crash severity.
1972-02-01
Technical Paper
720969
V. R. Hodgson, M. W. Mason, L. M. Thomas
Abstract A human head model has been developed primarily for use in evaluation of impact attenuation properties of football helmets, but is also applicable in automobile impact safety tests. Using firm silicon rubber molds made from impressions of cadaver bones, a skull and mandible were each cast in one piece using a self-skinning urethane foam that hardens into cross section geometry similar to the human bone. A rubber gel material is used to simulate the brain. The skull and attached mandible are overlayed with repairable silicon rubber skin having puncture and sliding-over-bone characteristics similar to human skin. At present, the model has a rudimentary solid silicon rubber neck, through the center of which runs a flexible steel cable attached at the foramen magnum. The cable is used to attach the head to a carriage or anthropometric dummy and can be adjusted in tension to give various degrees of flexibility.
1972-02-01
Technical Paper
720972
James H. McElhaney, Verne L. Roberts, John W. Melvin, William Shelton, Albert J. Hammond
This paper discusses the development of adequate criteria and evaluation methods for seat belt restraint design. These criteria should include the effect of seat belts in abdominal injury as well as head injury. It is concluded that belt load limiters and energy-absorbing devices should limit head-to-vehicle contact, ensure that the lap belt maintains proper contact with the bony pelvic girdle, and limit the belt loads. Studies are made of pulse shape and belt fabrics. Currently available mathematical models are used for the studies included in the paper.
1972-02-01
Technical Paper
720973
D. Cesari, R. Quincy, Y. Derrien
Studies of the effectiveness of safety belts were carried out under various directions of crashes, including dynamic sled investigations, destructive barrier tests, and impact tests. The studies showed that three-point belts were effective in frontal impact from 0-30 deg, but that their effectiveness diminished after 45 deg because the belt slips off the chest. The three-point belt did not provide protection for the knees. The studies also pointed out that the anchorage system of the belt is a very important factor in its effectiveness.
1972-02-01
Technical Paper
720959
C. C. Culver, R. F. Neathery, H. J. Mertz
Abstract A viscoelastic neck structure that responds to impact environments in a manner similar to the human neck is described. The neck structure consists of four ball-jointed segments and one pin-connected “nodding” segment with viscoelastic resistive elements inserted between segments that provide bending resistance as well as the required energy dissipation. Primary emphasis was placed on developing appropriate flexion and extension responses with secondary emphasis placed on axial, lateral, and rotational characteristics. The methods used to design the resistance elements for the neck structure are discussed. Three variations of the resistive elements have been developed that meet the response characteristics based on the data of Mertz and Patrick. However, no single resistive element has satisfied the flexion and extension characteristics simultaneously, but such an element appears to be feasible.
1972-02-01
Technical Paper
720962
D. H. Robbins, R. O. Bennett, B. M. Bowman
Abstract During recent years, the Highway Safety Research Institute (HSRI) has developed and validated two- and three-dimensional models describing the motions and forces acting upon an occupant during a collision. These inexpensive-to-operate models are performing with approximately 90% accuracy in parametric studies of classical crash configurations. In our own validation procedures, contacts with automobile development and design groups, and discussions with federal agencies, certain shortcomings of mathematical modeling procedures have been isolated. These include primarily the inability of the user to determine and input data to the computer programs and also to specify force, motion, velocity, and acceleration output data in a form applicable to the various vehicle design, human tolerance, and compliance tasks for which the models have been developed.
1972-02-01
Technical Paper
720961
John A. Bartz
A three-dimensional mathematical model of the crash victim has been developed and experimentally validated at the Cornell Aeronautical Laboratory. The digital computer simulation includes a body dynamics model of 40 degrees of freedom and a contact model that generates forces from contact with vehicle surfaces and between body segments of the crash victim, and restraint forces from belts and inflatable restraints. The validity of the computer simulation was determined from comparisons of predicted responses with those measured in various experiments, including static bench tests, pendulum tests, impact sled tests, and a full-scale automobile crash test. Inputs to the computer program were based on detailed measurements of dummy characteristics and measured properties of the contact surfaces and restraints.
1972-02-01
Technical Paper
720964
Edward B. Becker
Procedures to determine the center of mass and the moments of inertia in three dimensions of previously defined anatomical segments are presented. As an illustration, these procedures are applied to the human head and head-and-neck. The results of measurements made on six human heads and three head-and-necks are presented and discussed.
1972-02-01
Technical Paper
720963
Roger C. Haut, Charles W. Gadd, Richard G. Madeira
This study explores the application of viscoelastic modeling for characterization of the response of the brain to impulsive loading with the objective of learning whether such models could exhibit the same time dependency of strain or likelihood of injury, as exhibited by the Severity Index, HIC Index, Wayne Tolerance Curve, and other similar representations of tolerance. The mathematical relationships between viscoelastic properties and the corresponding time dependency of tolerance are shown for Newtonian, Bingham plastic, and Pseudo-Bingham, as well as more general behavior. Preliminary static and dynamic tests upon small mammalian material are described with particular attention given to strain in the vicinity of the brainstem as a function of loading profile. Both the theoretical and experimental results show that the falling time dependency of the above indexes can be interpreted in terms of nonlinear viscoelastic response.
1972-02-01
Technical Paper
720848
Harold D. Altis
The role of experimental prototypes in aeronautic advancements is discussed. Two flight regimes are identified for exploration through new prototype projects: sustained supersonic/hypersonic flight and general purpose VTOL aircraft. Specific aircraft design approaches are presented.
1972-02-01
Technical Paper
720854
D. H. Bennett, R. P. Johannes
Advanced design studies indicate that use of “control configured vehicle” (CCV) concepts can provide improvements in combat capability and versatility. These benefits will be evidenced by improved performance and survivability, as well as by new maneuvering capabilities not available to pilots of current aircraft. The fly-by-wire (FBW) techniques, utilized to enable CCV, also provide the potential for improved flying qualities. The end result of applying these concepts in the preliminary design stages can be a lighter weight fighter aircraft to do a given job better.
1972-02-01
Technical Paper
720843
E. A. Lamont, H. G. Diem
This paper describes propulsion systems under consideration for orbital maneuvering stages (Space Tug or Orbit-to-Orbit Shuttle). It describes the Space Tug/Orbit-to-Orbit Shuttle (OOS) configurations, and the missions to be performed by the Space Tug/OOS. The propulsion system requirements for the Space Tug/OOS main engine and the attitude control systems are described. The effect of the mission and operational requirements on the main engine system characteristics (for example, start, stop, throttling, reuse, life, etc.) are described. A listing of the propulsion system candidates for this application is provided. Briefly described are existing systems such as Delta, Agena, Centaur, and Transtage. New engine systems (the Staged Combustion engine and the Aerospike engine) for this application are described in greater detail.
1972-02-01
Technical Paper
720858
F. A. Wirth
In order to assure delivery of a flight training simulator while flight testing is incomplete and several months ahead of the delivery of its counterpart aircraft, new and unusual methodology must be applied. Such methodology, called positive interface management, has been developed and successfully applied to the DC-10 program by American Airlines. This paper is a case study of this application.
1972-02-01
Technical Paper
720860
S. B. Moore
This paper presents considerations in formulating test requirements for public ground transportation programs. Ground transportation systems are categorized by function, speed, subsystem characteristics, etc., in order to aid in establishing requirements of test engineering technology, test laboratories, and test facilities. Current LTV public transportation programs are used to exemplify the general test requirements of systems proposed to fill the current and projected needs of society.
1972-02-01
Technical Paper
720856
Wallace H. Deckert, Robert C. Evans
This paper is an overview of the status of lift fan transport technology. Selected results of recently completed NASA in-house and contractual research investigations are included within the general areas of lift fan transport design: propulsion, acoustics, integrated propulsion/airframe/aircraft control systems, piloted moving-base simulation, and aircraft aerodynamics. On-going NASA lift fan transport research is briefly summarized, and a possible next step in the overall program is suggested.
1972-02-01
Technical Paper
720923
S. A. Lippmann
As highway development programs brought increased truck traffic through formerly isolated communities, public sensitivity to truck tire noise increased significantly. Industry was alert to the possible consequences of social and legal pressures and acted in concert to set up standards for noise control and for establishing criteria by which to measure annoyance levels. Work by several leading associations provided a starting point for investigations by the SAE Truck Tire Noise Subcommittee. The Subcommittee's efforts resulted in formulation of a tire testing procedure and a consolidation of requirements to be incorporated into a proposed standard. This paper reviews the objectives and approaches of the Subcommittee and serves as an introduction to the accompanying papers.
1972-02-01
Technical Paper
720918
C. N. Hostert
The deterioration of secondary ignition wiring life on today's internal combustion gasoline engine has created many maintenance problems in the field. The mandatory use of TVRS (resistance wire) has amplified these problems and made them more difficult to solve. The solution does not lie solely with wire design-engine application, engine design, and component selection and location are also important factors. THE LIFE SPAN of the secondary wiring used on gasoline automotive engines dropped dramatically with the introduction of resistance-type wire which is commonly referred to as TVRS wire. The TVRS wire was introduced to suppress ignition interference in accordance with SAE specifications, and to meet the requirement of Public Law 200 passed in October 1951. The TVRS wire was also intended to reduce spark plug electrode erosion. While both of these missions were accomplished, in most cases the wire had a very short life.
1972-02-01
Technical Paper
720877
C. W. Formwalt, J. L. Frank
This paper discusses the Dynamometer System of Accurate, Unambiguous Readouts (Dinosaur), a new system used in the performance testing of engines at John Deere. Readouts are digital, and data are in engineering units; thus, the engineer supervising the test can make decisions regarding the conduct of the test while there is still time to modify the test program. Testing time is reduced as the operator need not perform calculations, data conversions, etc. Test setup and teardown time is minimized by checking all instrumentation transducers for proper operation prior to the test at which time a bulkhead system with quick-disconnect connectors is utilized. Among the subjects discussed are the operation and design of Dinosaur, the method of digital computation, and the use of a new programmable-cascadable frequency divider.
1972-02-01
Technical Paper
720929
S. A. Lippmann
The A-weighted sound level accounts for the bulk (but not all) of the jury's reaction to the sound of trucks coasting on a variety of tires. A component of the jury's reaction is related by the study to the manner in which the sound decays after the vehicle passes the point of observation. This component also appears to depend strongly on the characteristics of the sound. The jury's reaction shows two forms of distortion: end-of-scale compression and temporal drift. The analysis attempts to account for these factors and to see beyond them into the jury's basis for reacting.
1972-02-01
Technical Paper
720928
Ralph K. Hillquist
The SAE Truck Tire Noise Subcommittee, as a part of its efforts toward writing a measurement and evaluation procedure, conducted an experimental test program for relating objective and subjective assessments of truck tire noise. The program comprised a series of designed experiments involving 6 trucks, 18 sets of tires, and 5 vehicle operating modes. The test runs were presented in random fashion to a jury situated alongside a highway. The subjective noisiness ratings and the A-weighted sound levels obtained verified the design objectives of the experiment and, further, correlated well with each other.
1972-02-01
Technical Paper
720927
Gerald M. Dougherty
A noise standard is acceptable only if it isolates the area of concern (tire sounds), correlates to human response, and is repeatable, easily understood, and economically feasible. With these goals attained, the SAE Subcommittee on Truck Tire Noise proposes their recommendations on “Sound Level of Highway Truck Tires-Recommended Practice SAE XJ57.” Part I of this paper contains the final draft of the test procedure that the Subcommittee has proposed to SAE committees as a recommendation. Part II explains and supports the Subcommittee's decisions for the recommended specification.
1972-02-01
Technical Paper
720926
G. R. Thurman
The nature of the sound produced by running truck tires is primarily due to the tread pattern design. At 50 mph the sound consists of a fundamental in the frequency range 300-400 Hz and of several higher harmonics. Each of these harmonics, including the fundamental, may consist of several separate frequencies; however, the spread of these frequencies is less than one-third octave. The singing, persistent sound produced by certain tire designs is shown to be associated with the level of the higher harmonics, particularly the third and fourth.

Filter

  • Range:
    to:
  • Year: