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Technical Paper

A Priori Analysis of Acoustic Source Terms from Large-Eddy Simulation in Turbulent Pipe Flow

2020-09-30
2020-01-1518
The absence of combustion engine noise pushes increasingly attention to the sound generation from other, even much weaker, sources in the acoustic design of electric vehicles. The present work focusses on the numerical computation of flow induced noise, typically emerging in components of flow guiding devices in electro-mobile applications. The method of Large-Eddy Simulation (LES) represents a powerful technique for capturing most part of the turbulent fluctuating motion, which qualifies this approach as a highly reliable candidate for providing a sufficiently accurate level of description of the flow induced generation of sound.
Technical Paper

Innovative Acoustic Material Concept Integration Into Vehicle Design Process

2020-09-30
2020-01-1527
Integration of acoustic material concepts into vehicle design process is an important part of full vehicle design. The ability to assess the acoustic performance of a particular sound package component early in the design process allows designers to test various designs concepts before selecting a final products. This paper describes an innovative acoustic material concept which is easily integrated in a design process through the use of a database of Biot parameters. Biot parameters are widely used in the automotive industry to describe the physical interactions between the acoustics waves travelling through foams, fibers or metamaterials and the solid and fluid phase of these poro-elastic materials. This new acoustic material concept provides a combination of absorption, transmission loss and added damping on the panel it is attached to.
Technical Paper

Inter-Laboratory Characterization of Biot Parameters of Poro-Elsastic Materials for Automotive Applications

2020-09-30
2020-01-1523
Automotive suppliers provide multi-layer trims mainly made of porous materials. They have a real expertise on the characterization and the modeling of poro-elastic materials. A dozen parameters are used to characterize the acoustical and elastical behavior of such materials. The recent vibro-acoustic simulation tools enable to take into account this type of material but require the Biot parameters as input. Several characterization methods exist and the question of reproducibility and confidence in the parameters arises. A Round Robin test was conducted on three poro-elastic material with four laboratories. Compared to other Round Robin test on the characterization of acoustical and elastical parameters of porous material, this one is more specific since the four laboratories are familiar with automotive applications. Methods and results are compared and discussed in this work.
Technical Paper

Study of the Glass Contribution to the Interior Acoustics of a Car and Related Countermeasures

2020-09-30
2020-01-1585
This paper shows that the collaboration between a glass manufacturer and a passive acoustic treatment manufacturer can bring different benefits and considerably improve the interior acoustics of a vehicle. In terms of passenger safety and well-being, glazing have always played a key role by offering solutions to interior comfort, particularly when it comes to heat and acoustics. Today, cars are becoming a living space which from an acoustic point of view brings a challenge for the interior comfort. Indeed, glazing has no absorption and classically it has an acoustic insulation weakness around its coincident frequency. In most of the cases, these different aspects make glazing one of the main contributors to the sound pressure level in the passenger compartment, and the trend is not one of change. However, there are possible countermeasures. One of which is the use of laminated glazing with acoustic PVB.
Technical Paper

The Large-Scale Operator's Influence on Design and Construction

1928-01-01
280034
TO solve fleet-operation problems successfully, a professional consciousness is needed among the supervisors and the engineers engaged in the operating field, awakened by analyzing and making known generally the methods and practices used by the operators of individual fleets of motor-vehicles, according to the author. In developing his subject he asks the following questions and comments upon them: Has the operator any influence on design? Is that influence good or not? Whatever the influence is, can it be improved and made more effective? If it can be made more effective, how can this be done? If it cannot be made more effective, what is the reason? Regardless of variations in duties and of conditions in organization, each large-scale operator is vitally concerned with matters of design and construction.
Technical Paper

Automobile Bodies, from the Abstract Customer's Viewpoint

1928-01-01
280057
CONSTRUCTIVE criticism of automobile bodies as now built is given herein, based on experience gained in driving five-passenger sedan cars of many makes a total distance of nearly 10,000,000 miles in one year in tests at the General Motors Proving Ground. The fault finding, although humorously exaggerated, will be valuable if taken seriously, as it gives to all body designers and builders the benefit of testing experience that few companies are in a position to gain at first hand. The author treats his subject from the viewpoint of the abstract customer; that is, the automobile-purchasing public as a whole and as represened by the imaginary average man, who is assumed to have average stature and body structure and to drive all the different makes of car. Thus he is assumed to change from one to another make frequently, instead of becoming used to only one or two cars.
Technical Paper

How the Ford Company Gets Low Production Costs

1928-01-01
280063
ECONOMIC factors applying to mass production are dealt with in an endeavor to show how, by following certain laws of manufacturing management based on economic laws, the Ford Motor Co. has attained its very low production costs. Some of these laws, which were put into concrete form as recently as 1926 by L. P. Alford, are quoted, and examples of methods are given to show how they operate.
Technical Paper

Automobile Induction-Systems and Air-Cleaners

1928-01-01
280051
AFTER indicating the trend of requirements in induction systems, the author discusses air-cleaners, carbureters and inlet manifolds. Particular attention is paid to improvements in centrifugal air-cleaners, that result in only slight pressure loss and in high cleaning efficiency. These improvements have been made by changing the body outline; by the addition of a diffuser, to make the resistance as small as possible; and by proportioning the vanes, as to angle and number, to increase the cleaning efficiency with only slight loss in pressure. Carbureters are considered briefly, only because of their interrelation with air-cleaners and manifolds. Inlet manifolding for four, six, and eight-cylinder-inline engines is studied, with variations in port arrangement. Recommendations are made as to the cross-sectional areas and form to secure best distribution of the mixture and adequate vaporization.
Technical Paper

Aircraft Propellers

1929-01-01
290059
NEARLY all the aircraft propellers used by both the Army and the Navy are of the detachable-blade type. The Navy has found it necessary to make its own designs and to furnish the propeller manufacturers with finished detail drawings. The author lists the sources from which data can be obtained and shows a chart from which can be found a diameter and setting of a pair of detachable blades that will give reasonably good performance for nearly any horsepower, revolutions per minute and airspeed commonly used with the direct-drive type of propeller. Discrepancies between model tests and wind-tunnel tests are cited, and the author then considers the subject theoretically. Substitute propellers are next considered, and also the strength of propellers.
Technical Paper

Specification-Writing for Petroleum Lubricants

1927-01-01
270061
ALL large users of petroleum lubricants are endeavoring to reduce to printed form their individual ideas of what the lubricants they want should contain and what their physical and mechanical properties should be. The lubricants manufacturer finds, however, that anarchy prevails among the requirements and that the technique of writing the specifications is distinctly amateurish. One method followed is to analyze a satisfactory lubricant and embody the results in the specifications, but the specifier does not know that the product is the best for his purpose and does not possess the facilities for accurate analysis and the ability to determine the pertinent from the irrelevant factors. Another method is to select from a number of analyses and specifications items that seem important and incorporate them in the writer's specification. The result calls for a non-existent hybrid that may be impossible to produce.
Technical Paper

Airplane Lighting Requirements

1929-01-01
290067
INCREASE in the amount of night flying with the advent of airplanes into the commercial field makes more acute the need for proper lighting facilities, not only of airports and airways, but of the airplanes themselves. As only about one-half of the regularly used airways in this Country are lighted for night flying, and few airports are equipped with lighting facilities for night landings, it is necessary for airplanes to be provided with lighting equipment for flying and for emergency landing at night. Besides the high-intensity lighting needed for following unlighted airways and for landing, airplanes need navigation lights and illumination for the instruments and the cabin. Immediate study and direction should be given to the problems of meeting each of these requirements most effectively and economically before it becomes too difficult to standardize methods and equipment.
Technical Paper

Accounting for Depreciation as a Production Cost

1929-01-01
290070
IF the costs of almost any group of manufacturers who market the same product are analyzed, two kinds of differences will be detected, according to the author. The real differences in costs arise from superior management, higher productivity, and better disposition and utilization of capital. The accidental differences result from the failure of manufacturers to include in cost records all of the proper legitimate items of expense. Confining his treatment of the subject to an analysis of the depreciation of plant and equipment, the author states that depreciation is a decline in the value which is certain to occur as a result of wear and tear and gradual obsolescence. It is caused by the possession and use of an asset, and is therefore a part of the cost of production. The accountant attempts to recover depreciation loss in the value of the capital assets by charging it into the cost of production.
Technical Paper

Structure of Six-Wheel Vehicles

1929-01-01
290073
RIGID six-wheel vehicles and semi-trailer combinations are classified and described as to load distribution, application of power, arrangement of spring suspension and of tires. Consideration is given to the desirability of a conventional differential between the two driving axles, and the advantages to be gained by substituting a differential in which the action is limited. The semi-trailer is said to be useful for specialized services and to compete rarely with the rigid six-wheeler. The automotive industry is said to be following in the steps of railway engineers in providing more wheels for greater loads. At the close of the paper is given a bibliography of S.A.E papers and general periodical literature referring to six-wheel vehicles.
Technical Paper

Applying the Motor-Vehicle to Business

1929-01-01
290081
MANY FACTORS gradually forced a recognition of motor-vehicles as necessary adjuncts to business, and now the motor-vehicle is being called upon more than ever before to serve also as a labor-saving device. The author believes that present-day business will demand further development of this nature. The groups interested in establishing and developing the motor-vehicle in business are the manufacturers thereof, the commercial organizations operating vehicles for their individual needs, the commercial operators supplying service for a variety of customers, and the railroads. The author pays tribute to the manufacturers for the present dependability of motor-vehicles and comments upon the extension of motor-vehicle service in the respective fields of the three other groups. Present competition in all forms of business makes the problem of cost accounting equally serious for all users of commercial vehicles, in the author's opinion.
Technical Paper

Motor-Vehicle-Fleet Economics

1929-01-01
290082
THE TECHNICAL requirements of motor-vehicle-fleet operation are receiving increasing attention, according to the author, who analyzes two distinctly different plans for fleet organization; one, that of providing for sufficient man-power to care for all repairs, and the other, of later origin and requiring a much smaller organization, the delegation of all repairs to the specialists of the commercial repair-shops. In analyzing these plans he considers a fleet of 500 vehicles. His analysis of the latter plan has to do with a fleet organization having no shop personnel and a total of 10 or more vehicles per employe, the fundamental requirements in this case being the provision of qualified inspector-repairmen and efficient manufacturers' and commercial service-stations.
Technical Paper

Long-Distance Passenger Services

1929-01-01
290083
EXTENSION of motorcoach services over routes of 100 miles or more in length in all parts of the Country is shown by a map, and figures are given of the number of routes, the miles of highway over which the services are operated, running time, rates of fare charged and like data. Facilities and operating methods differentiating long-distance from suburban services are mentioned and the similarity to railroad practice pointed out. A characteristic of routes ranging from several hundred to nearly 1500 miles is that service is afforded continuously for 24 hr. per day seven days per week and many passengers ride day and night. Such long runs are broken into stages so that a driver does not work more than 8 to 10 hr. as a rule and vehicles are changed at the end of a run of a certain distance, which may vary from about 200 to nearly 750 miles.
Technical Paper

Mixture Distribution

1930-01-01
300007
HOPING that discussion and dissemination of information on the fundamentals of distribution routine will continue, the author reiterates known facts, which include (a) the method of charting distribution progress, (b) a suggestion for locating the error in distribution and (c) a series of thoughts on construction. The paper is divided into two parts, the first being a study of distribution routine and the other a discussion of a few of the problems that are met every day in the search for perfect distribution. Complete satisfactory distribution and the quantitative measurement of its quality are the two major problems of distribution. The interrelation of these problems is mentioned and the complexity of the subject of distribution is emphasized by listing nine detailed factors, the point being made that if the information that engineers have on these items could be collected and codified considerable progress would be made.
Technical Paper

Bearing Bronzes with Additions of Zinc, Phosphorus, Nickel and Antimony

1930-01-01
300012
SEVEN basic copper-tin-lead bearing-bronzes having high copper contents were studied by the application of various mechanical tests, such as Brinell hardness, resistance to impact, resistance to repeated pounding and resistance to wear. The effects of various additions were investigated by preparing test bearings of the same base alloys with additions of zinc, phosphorus, nickel and antimony, taken singly, and applying the same tests to these. The preparation of the test castings and the methods of testing are described in detail. The chemical analyses are given for the 40 different alloys tested; and the results of the various tests on each group of alloys are reported and discussed in detail, with the observations charted and tabulated for convenient reference. A tabulation of the specifications of 54 different bearing bronzes now in use is included in the paper. Dr. Dowdell presented and discussed∗ the paper for the authors.
Technical Paper

Future Clutch Progress Charted from Design A-B-C's

1933-01-01
330011
FIRST consideration is given by the author to basic improvements in clutches of the lever-release single-plate and to those of the two-plate types. He emphasizes that the severity of clutch service has increased very materially in the last few years and that the increased clutch duty of today is further augmented by the car manufacturer in providing cars having greater acceleration and higher torque, particularly at the higher speeds and usually without a proportionate increase in clutch size. Developments along logical lines which have resulted in improvements in design are cited as being (a) the design of the driven disc and the selection of facings, to produce improved engagement and greater life; (b) design of the cover-plate assembly to permit higher spring pressure with less retracting movement of the pressure plate; and better selection of facing and pressure-plate materials to reduce facing wear and pressure-plate distortion or scoring.
Technical Paper

Correlation of Propeller and Engine Power with Supercharging

1933-01-01
330005
THE primary purpose of this paper is to discuss some of the most pressing problems involved in choosing the propeller that is most suitable for use on a particular airplane. Propeller design is not dealt with, the discussion being limited to the selection of metal propellers of established design. Questions of noise, efficiency and diameter limitation are merely mentioned, and the emphasis is placed upon the choosing of propellers which will transmit the most engine power for the most needed condition of airplane performance; maximum and cruising speeds at altitude, or take-off and climb. Airplane performance enters only inasmuch as it is used to illustrate a case of power absorption. The proper choice of a propeller is becoming increasingly difficult to determine because of the current design trends of both airplanes and engines. Especially important is the fact that many of the supercharged engines now in use cannot be operated at full throttle below their critical altitudes.
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