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Viewing 163861 to 163890 of 189417
1973-02-01
Technical Paper
730337
B. E. Kaminski
This paper presents a brief review of some of the contributing factors in design for fatigue and fracture of advanced composite materials. Consideration is given to the roles which the fiber and matrix have in the static, fatigue, and fracture response of laminated composites. The statistical aspects of failure are also discussed.
1973-02-01
Technical Paper
730338
Charles W. Bert, Karl H. Bergey
This paper describes a rational basis for making tradeoff decisions on cost and weight for structures made of various materials. Unit cost and empty weight data have been gathered for a variety of consumer products and of aircraft. As examples illustrating potential applications of filamentary composites, the cost/weight tradeoff ratios were calculated for three typical aircraft structural components: a landing-gear cantilever-spring strut, an I-beam, and a shear panel. In addition, weight analyses of fuselage structures were made for designs using a variety of materials and these structural concepts: monocoque, sandwich, and ring-and-stringer-stiffened cylinders. With the cost reductions anticipated in the next three or four years for graphite and boron filamentary composites, fiber composites hold considerable promise for general-aviation aircraft.
1973-02-01
Technical Paper
730333
Howard Chevalier, Joseph C. Brusse
Stall/spin airplane accidents result in a significant number of fatalities each year within the general-aviation community. The most effective method of reducing this type of accident is to prevent airplane stalls. The device described in this report has been shown to be effective in preventing stall of a Piper PA-18, 150 airplane, and it should also be effective on other airplanes. The system incorporates a small spoiler mounted on the under surface of the stabilizer near the elevator hinge line. The spoiler is deployed automatically by means of a servo system that receives its commands from an angle of attack sensor mounting in the wing leading edge. Thus, the operation of the system is independent of pilot reactions. The spoiler deploys to limit tail power near the wing stall angle of attack, thereby preventing the wing from reaching the angle of attack required for stalling.
1973-02-01
Technical Paper
730334
G. S. Weislogel
The general aviation pilot outnumbers his airline counterpart 30:1 and flies five times as many hours each year. General aviation, defined as all civil flying activity except that performed by the public air carriers, is a heterogeneous population of airmen including the weekend pilot flying a “Cub” to the versatile corporate pilot flying a $3 million corporate jet. Until recently little has been known about the operational profiles of the different categories of general aviation pilots, resulting in judgments about their operations which are a priori at best. Under the direction of the Federal Aviation Administration Systems Research and Development Service, studies have been conducted which yield for the first time quantitative measures useful in describing the nature of certain categories of general aviation pilots and their flight operations. Study findings are expected to have implications for airman certification standards, flight safety regulations, and aircraft design.
1973-02-01
Technical Paper
730579
Om Johari, William A. Sipes
A comprehensive scanning electron microscope(SEM) survey of the fracture surfaces of an aircraft main landing gear shock strut piston showed that improper shot peening contributed to the initiation of the anamolous fatigue failure. SEM photographs of the suspect-origin regions and the surrounding areas were analyzed. The photographs are presented, along with a detailed description of the regions observed. Failure mechanism is discussed, and causes of fracture origin explored.
1973-02-01
Technical Paper
730580
J. P. Sheehan, M. A. H. Howes
An investigation of the influence of surface roughness of lubricated rolling-sliding contact surfaces on pitting fatigue has been carried out. A significant increase in pitting resistance resulted from polishing the ground mating surfaces. When the roughness of the loading rollers (positive slip element) was reduced from 10-15 to 5-9 μin rms and that of the test specimen (negative slip element) from 10 to 2-3 μin rms, there was a gain of about 150% in load-carrying capacity before pitting occurred. The surface roughness of the loading roller appears to be the dominating factor. The degree of metallic contact and surface distress decreases when the roughness of the roller approaches the thickness of the oil film.
1973-02-01
Technical Paper
730582
K. D. Bird, J. F. Martin
A new tire research facility (TIRF) has been developed which uses appropriately surfaced steel belts to provide high-speed, flat, simulated roadway surfaces for measuring the forces and moments generated by pneumatic tires at various operating attitudes, loads, and speeds. Descriptions of TIRF and several of its important features are presented. These include the method of support of the moving roadway beneath the tire contact patch, the method of maintaining belt tracking under high side loads, the balance system used to measure forces and moments, and the computer control system used to operate and control the machine and completely process the data. Machine performance specifications and typical data are included.
1973-02-01
Technical Paper
730583
I. Litant
A program is underway at the DOT/Transportation Systems Center to study the nondestructive detection of defects in tires, and to determine the relationship between these defects and tire failure. Ultrasonics, x-ray, infrared, holography, and other techniques are being used to determine their effectiveness as well as their limitations in this task. This paper describes the use and modification of the equipment for nondestructive inspection of new and retreaded tires. It also describes the use of a computer data bank for data collection, storage, and retrieval in the correlation of results.
1973-02-01
Technical Paper
730584
James O'Day, William L. Carlson
Several sets of both police-reported and in-depth traffic accident data are queried with respect to the involvement of vehicle malfunctions or defects in accident causation. It is concluded that accident-causing defects are inconsistently reported, are often attributable to the lack of appropriate maintenance practices, and are evidently not being corrected by present motor vehicle inspection systems. Although vehicle malfunctions are less frequently identified as accident causes than either human or environmental factors, they are noted often enough to be considered a problem. It is suggested that the automotive engineer has already built into the vehicle many detection systems which serve notice to the vehicle owner/operator that a component needs attention. Finally, it is suggested that further efforts in this direction may supplement state authorized periodic inspection programs in minimizing the incidence of vehicle defects in accidents.
1973-02-01
Technical Paper
730585
R. R. Love, C. W. Ewing
This paper reviews the automobile development process, highlighting improvements that have been made. New model development is described first, followed by discussions of proving grounds testing and test facilities. Some of the product changes which have resulted from these processes are enumerated in the areas of corrosion protection, lubrication, electronics, customer comfort and convenience, tires and brakes, and safety and security. Finally, a product comparison is presented of a 1958 model automobile versus a 1973 model of a comparable automobile.
1973-02-01
Technical Paper
730587
James Mateyka, Richard Danzeisen, David W. Weiss
“Fault tree” is a name given to a logic diagram that develops all of the subsystem and component faults and combinations of faults which can result in particular system symptoms or faults. This type of logic diagram can be extremely useful in all phases of automobile design and service. Applications are discussed to the following areas: 1. As a reliability tool for identifying and cataloging specific problems, to preclude their being incorporated in new designs. 2. As a diagnostic aid to maintenance personnel in systematically screening potential vehicle performance problems. 3. As an aid in assessing accident causation factors and the potential contribution of vehicle defects to accidents. Examples in each area are presented. Particular emphasis is placed on the value of such logic diagrams over conventional troubleshooting charts and manuals in aiding mechanics to pinpoint specific problems.
1973-02-01
Technical Paper
730586
Richard M. Miller
Increased emphasis upon achievement of customer satisfaction has forced American Motors' quality and reliability activities to develop new techniques for identifying and correcting field product problems. This paper will describe the features of the American Motors' Buyer Protection Plan; will review methods used to provide product problem information feedback; and will discuss fleet performance reporting, new model dealer reaction surveys, warranty parts return programs, and specialized warranty analysis. The unique product problem and action status reporting procedure developed to provide a uniform coordinated method for investigation, recording and resolution of field quality problems will be presented. Sound communication and motivational techniques exercised within the organization enable prompt reaction to implement the message of the Buyer Protection Plan.
1973-02-01
Technical Paper
730572
K.N. Sundaram
Piezoresistive phenomena found in silicon semiconductors and the possibility it has of integrating various electronic functions (all in one family of technology) are a viable method of meeting the future requirements of the automotive industry. After a brief discussion of the evolution of semiconductor sensors and the “state of art” design, the author proceeds to propose some suitable circuits for integration of electronic functions such as comparator, amplifier, A to D converter, etc. Although the discussion centers on pressure transducer design, the facts in the example can easily be transferred to temperature, flow, and acceleration measurements.
1973-02-01
Technical Paper
730571
Paul F. Bennewitz
Unlike lithium chloride, chemical, and other surface-type elements, the Brady Array exhibits bulk effects conforming to the Poole-Frenkel law concerning bulk phenomena. Other types of sensors require agglomeration of water or moisture prior to measurement; in the array, measurements are accomplished at a discrete molecular level, resulting in extremely rapid response and recovery times (better than 150 ms). Stressed bonds within the structure initiate rapid recovery by purging the sensor when it is moved from higher to lower values of relative humidity. The sensing element is contained within a TO-5 type transistor housing, measuring only 10 mil in diameter and 100 mil in length. The array has been operated over temperature extremes ranging - 200 to +800°F without damage or loss of calibration. The technique employed in the array also lends itself to sensing of other gases, when constructed using techniques proprietary to Thunder Scientific Corp.
1973-02-01
Technical Paper
730574
Don Payne
The requirements of aerospace programs have brought about refinements in the fabrication of small precision pressure transducers in recent years. This paper describes the Gulton Model GS-1 pressure transducer, which was designed primarily for installation on automobiles. Considerations in its development were: corrosive or solvent characteristics of the pressure media commonly encountered in the automobile engine compartment; vibration and shock levels; electromagnetic interference constraints; temperature variations; calendar and cycle life; electrical power available; size and weight; mounting, including pneumatic and electrical connection; and cost. Design details for satisfying these considerations are discussed.
1973-02-01
Technical Paper
730573
H. R. Mitchell, R. N. McGill
Most transducers offered commercially are suitable for laboratory, aerospace, or industrial process applications but do not meet additional, stringent automotive requirements. A need exists, both present and future, for various types of transducers in automotive powerplant control systems. Possible electronic systems and subsystems requiring transducers are discussed, and the types of transducers needed for these systems are described along with a discussion of a general set of specifications with respect to accuracy, reliability, and durability. Substantial transducer development is needed to enhance the advancement of certain automotive electronic systems. This paper points out these requirements to the electronics industry in an effort to encourage a mutual industry development that will advance the technology.
1973-02-01
Technical Paper
730576
M. M. Bertioli
The particular difficulties encountered in designing fuel and ignition control in today's automobiles have led to consideration of electronic systems. These are totally dependent upon the transducers used to provide the information they require, and frequently the success of a given system depends upon the solution of some transducer problem. This paper discusses some of the alternative choices of input parameters to a control system intended to manage the fuel and ignition of an internal combustion engine. The requirements for, and designs for, transducers to measure throttle angle, crankshaft speed and position, air mass flow, engine component position, and exhaust quality are discussed.
1973-02-01
Technical Paper
730575
William J. Fleming, David S. Howarth, David S. Eddy
Various proposals for emissions cleanup systems have shown the desirability of regulating engine air-fuel ratio within precise limits. For this purpose a prototype exhaust sensor has been investigated. The sensor is a ceramic device, made of stabilized zirconia, which operates via electrochemical principles. It is placed directly in the exhaust stream and generates a voltage signal which is an approximate indication of engine air-fuel ratio. Several sensors have been installed in situ on engines operated under controlled dynamometer conditions. Fundamental response characteristics of the sensors have been determined. The results of this investigation, together with descriptions of the construction and installation configuration of the prototype sensor, are discussed.
1973-02-01
Technical Paper
730578
G. M. Marsh, A. D. Robb, T. H. Topper
The techniques and equipment discussed in this paper were developed in order to characterize the fatigue behavior of sheet steels ranging in thickness from 0.10-0.20 in. The unique developments consist of a specimen gripping and alignment device, and an inexpensive, highly sensitive diametral extensometer. Test results indicate that the combination of specimen geometry and specially designed grips performed satisfactorily, and that longitudinal and diametral specimens are satisfactory for strain amplitudes up to 0.75 and 7%, respectively. The techniques could be used to obtain axial fatigue data on sheet steel as thin as 0.100 in.
1973-02-01
Technical Paper
730577
Robert L. Cheney
This paper describes a diffused semiconductor strain gage pressure transducer designed for use as a manifold vacuum sensor in electronic ignition and electronic fuel injection systems. The design philosophy, construction, and the calibration techniques used to enable the subject transducer to perform accurately over a broad range of environments and maintain this performance for thousands of miles without periodic recalibration, are discussed.
1973-02-01
Technical Paper
730563
R. M. Oldershaw, A. F. Prestidge, R. C. Birkmyre
The paper illustrates the high degree of correlation now attainable with practical vehicle test results, using a reduced-scale dynamometer. The techniques for achieving this state-of-the-art are described in relation to the parameters generally known to influence vehicle/laboratory correlation. As a result of the investigation, the following additional parameters are submitted: history of pad use, correct temperature/time simulation of the car by the machine, and rate of work input during a test. The simulation item is the subject of a special study in which the thermal conditions in a brake are examined on an analog computer by means of a 2 d.f. model. A discussion of the possible applications of the scale dynamometer leads to the conclusion that a machine could now be developed to provide meaningful data on linings for the use of friction material, brake, and vehicle manufacturers, as well as legislators.
1973-02-01
Technical Paper
730564
Don Hollinger, Arv Mueller
This paper describes a technique for programming accelerated laboratory fatigue tests which is called the “peak-valley-pair” (P-V-P) method. As presented, the P-V-P method applies to automotive structural components which are insensitive to frequency and subjected to unidirectional loading. The P-V-P algorithm operates on the measured service responses of the component (displacement, load, strain, etc.) to yield the control signal for a laboratory fatigue test. Associated data processing and an example of this methodology are also presented.
1973-02-01
Technical Paper
730565
H. O. Fuchs, Drew V. Nelson, M. A. Burke, T. L. Toomay
The paper presents a method for shorter evaluation of the fatigue damage done by an irregular sequence of loads. The method looks first for the largest overall range from highest peak to lowest valley, then for the next largest overall range that interrupts the first range, and so on, down until a suitable fraction (for example, 10%) of all reversals have been used. These few reversals form a short history, which will do substantially the same damage as the total history. The process is applied to three long histories selected by the SAE Fatigue Design and Evaluation Committee. The sensitivity of calculated damage to the omission of smaller ranges is computed for plain and for notched specimens. The error is compared with differences produced by different current rules for evaluating damage, by different cycle counting methods, and by smooth specimen simulation of notched parts.
1973-02-01
Technical Paper
730566
Richard Zechnall, Guenther Baumann, Hermann Eisele
The Federal Standards pertaining to the exhaust emission control of the 1976 model year automobiles presumably demand the catalytic conversion of the pollutants involved. Provided the air-fuel ratio is maintained at a stoichiometric value, some problems (for instance, fuel economy) can be solved. A closed-loop system was developed, consisting of an electronic fuel injection system and a special oxygen sensor, called the λ-sensor, in the exhaust manifold. First results on vehicles indicate that this control system offers an promising solution to the reduction of harmful contaminants. The closed-loop system can be used with a three-way catalytic converter or with a dual-bed system. It has not yet been investigated whether the durability of the two systems is adequate, apart from the general problems of the durability of each catalyst.
1973-02-01
Technical Paper
730567
L. S. Bernstein, R. J. Lang, R. S. Lunt, G. S. Musser, R. J. Fedor
Latest results with dual catalyst systems incorporating GEM nickel-copper alloy NOx reduction catalysts are reported. Progress in optimizing system design to provide rapid warmup, maintenance of operating temperature, and controlled carburetion to maximize NOx removal and minimize the risk of over-temperature is discussed. Results of vehicle durability tests of GEM catalysts run on dynamometers are also presented. Rapid warmup of the catalyst system can be obtained by keeping NOx reduction catalyst mass low and utilizing the ability of the reduction catalyst to oxidize CO, H2, and HC under net reducing conditions. This ability to oxidize CO, H2, and HC is also used to maintain system operating temperature. Carburetion is controlled to ±0.4 A/F with a four-barrel research carburetor, the design of which is described in detail.
1973-02-01
Technical Paper
730568
H. R. Jackson, D. P. McArthur, H. D. Simpson
Hundreds of catalysts have been evaluated in bench activity tests, using synthetic engine exhaust gas to determine conversion of NO to N2 and NH3. Many of these catalysts were also exposed to actual engine exhaust in an engine-dynamometer test, and then re-evaluated in the bench apparatus to determine the degree of catalyst deactivation. For catalysts prepared on nonreactive, hydrothermally stable support materials, it was found that the primary causes of deactivation were sulfur and lead poisoning. Subsequently, it was determined that deactivation of a NOx catalyst from sustained exposure to engine exhaust can be closely simulated by impregnating the fresh catalyst with lead acetate to the required lead level, followed by testing the catalyst with SO2 present in the synthetic exhaust gas. These studies have resulted in the development of catalysts showing high initial NOx conversion efficiency and little deactivation in engine tests.
1973-02-01
Technical Paper
730569
Charles R. Morgan, David W. Carlson, Sterling E. Voltz
Stringent emission standards have strongly affected the requirement for catalysts and catalytic converters. Since considerable emphasis is placed on cold-start performance, catalysts with lower density and higher oxidation activity at lower temperatures are required. Monolithic catalysts have been extensively evaluated in low-emission vehicles. This paper identifies the key phenomena associated with overtemperature and emission breakthrough problems in platinum monolithic converters.
1973-02-01
Technical Paper
730570
Gerald J. Barnes, Richard L. Klimisch
The use of relatively small catalytic converters containing alumina-supported platinum (Pt) and palladium (Pd) catalysts to control exhaust emissions of hydrocarbons (HC) and carbon monoxide (CO) was investigated in full-scale vehicle tests. Catalytic converters containing 70-80in3 of fresh catalyst were installed at two converter locations on the vehicle. Carburetion was richer than stoichiometric, with air-fuel ratios (A/F) comparable to those proposed for dual-catalyst systems containing an NOx reduction catalyst. The vehicle was equipped with exhaust manifold air injection. Homogeneous thermal reaction in the exhaust manifolds played a significant role in the overall control of HC and CO. Four Pt catalysts, three Pd catalysts, and one Pt-Pd catalyst were prepared and evaluated. Total metal loadings were varied 0.01-0.07 troy oz. Hydrocarbon conversion efficiencies varied 62-82%, measured over the 1975 cold-hot start weighted Federal Test Procedure.
1973-02-01
Technical Paper
730554
Thomas A. Huls
This paper presents the development of the concept of emission testing on a mass basis and the establishment of emission baselines and standards. Data from tests run on several fleets to establish equivalency factors between average exhaust emissions when testing according to the 1970 (7-mode), 1972 (CVS-C), and the 1975 (CVS-CH) federal test procedures are listed. These data were used to establish the 1972, 1973-1974, 1975, and 1976 standard values. Tests were run on 30 precontrol vehicles by both the 7-mode and CVS-C procedures to derive the factors used to translate the 7-mode procedure baseline data into equivalent CVS-C procedure baseline data for precontrol vehicles. These values were used to establish the 1972-1974 hydrocarbon (HC) and carbon monoxide (CO) light-duty vehicle standards. Similar tests were run on 138 1970 vehicles to establish standards for the CVS-C procedure that were equivalent to the 1970 standards using the 7-mode procedure.
1973-02-01
Technical Paper
730555
H. May, W. Müller, E. Plassmann, F. J. Dreyhaupt
In the scope of efforts at air purification, a registration system has been developed on behalf of the Ministry of Labor, Health, and Social Affairs of North-Rhine-Westfalia considering every kind of emission contributing to air pollution. The emissions of motor vehicle traffic, industry, small business and domestic furnaces are registered. The system establishes data with regard to place, time, duration, quantity, type, condition, and temperature of the emissions. The present state of investigation regarding motor vehicle traffic is discussed in this paper for the area of Cologne, West Germany.

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