bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrodynamic Mass Matrix for a Multibodied System
Authors: Sharp G. R. , Wenzel W. A.
Published: November 2010

A matrix technique is developed herein for generating the hydrodynamic mass matrix associated with a multimass system immersed in a liquid environment. The technique assumes that the liquid environment may be represented by a series of flow-channels and nodes. Flow-channels are introduced in the region between surfaces of neighboring solids, and nodes are used to connect two or more flow channels. It is assumed that the solid bodies undergo unidirectional motion and that potential flow theory is applicable. Equations for fluid flow in a variable area flow-channel are obtained by first developing the governing equations for fluid flow in a channel bounded by two parallel surfaces which may move in translation both perpendicular and parallel to the direction of flow. The continuity equation is then developed for an arbitrary node, and the general matrix equation for computing hydrodynamic mass obtained by applying the developed equations to a particular problem.
Vibratory Locomotion
Authors: Gaberson H. A. , Stone P. L.
Published: November 2010

A new method for accomplishing land locomotion by vibrating a mass attached to a skid has been developed. The mass oscillates in an inclined direction, upward and forward, downward and backward. On the up-forward stroke it lifts the skid and pulls it forward; on the down-backward stroke it pushes the skid into the ground and the increased friction inhibits backslide. The paper presents the essentials of the theory of operation, a design chart, and reports on experiments with test skids.
A Direct Method for Analysis of Branched Torsional Systems
Authors: Shaikh N.
Published: November 2010

A general and direct method for the analysis of branched systems is presented, in which transfer matrices are used in Holzer-type solutions. The method is shown here for torsional vibrations, but should be applicable to other branched systems. As presented here, this method is much different than the usual procedure found in the literature. Unlike other methods, no matrix inversions (or equivalent operations) are required to account for branches at a junction. A single determinant giving natural frequencies is arrived at irrespective of the number of branches and junctions. Thus the method is straightforward, compact, and economical for computer solutions.
Air and Power Requirements for the Vacuum Transport of Crushed Coal in Horizontal Pipelines
Authors: Konchesky J. L. , George T. J. , Craig J. G.
Published: November 2010

Pipelines were installed aboveground at the U. S. Bureau of Mines, Morgantown (W. Va.) Energy Research Center, to develop and evaluate different types of systems—vacuum or pressurized, horizontal or vertical—and to obtain information for the design and operation of a practical system. A previous publication [1] gave references on conveyance of lump-size solids, presented one of many concepts of pneumatic transportation of coal underground, and described the experimental system and its safety features. This paper presents the results of experiments in the vacuum horizontal transport of up to 2 1/2-in. coal through 2-, 4-, 6-, and 8-in. dia pipelines. Minimum air rates required to move the coal in full suspension and pressure losses resulting therefrom were related to coal and pipe variables in the form of empirical equations that were used in predicting minimum power requirements.
A Reversibility Ratio for Pressure Changes in Real Gases
Authors: Potter J. H.
Published: November 2010

A dimensionless ratio is proposed relating isenthalpic and isentropic changes in real gases. The new parameter meets the requirements for a property, and is shown to depend only upon the equation of state. Some possible applications are indicated.
Prediction and Measurement of Propulsion System Performance
Authors: Postlewaite John , Salemann Victor
Published: November 2010

The problem of predicting installed propulsion system performance for a specific configuration from isolated inlet, nozzle and airframe data, and from data for similar configurations is discussed. The degree to which element performance may be isolated from measurements made on an integrated propulsion system will be discussed. An approach to evaluation of external performance of inlets and nozzles is presented. The design of parametric tests and some correlations for afterbody pressure drag from such tests are described. Improvement of data quality from model tests with sophisticated simulation of propulsive flows by pretest studies and in-test quality control are proposed.
Design and Development of the 190-Ton Stable Semisubmerged Platform (SSP)
Authors: Lang T. G. , Hightower J. D. , Strickland A. T.
Published: November 2010

The general characteristics, design features, predicted performance, and construction highlights of the 190-ton Stable Semisubmerged Platform (SSP) are presented. The SSP is the first large manned version of a high-speed displacement craft concept having a small waterplane area. The SSP was designed to be a work platform for research and testing of advanced naval equipment at the Naval Undersea Center. Its unique design will provide an order-of magnitude improvement in motion reduction over monohulls, as well as provide more deck space and internal volume. The SSP is 89 feet long and has a top operating speed of 25 knots with about 25 tons of payload and fuel. Design of the SSP features two parallel torpedo-like hulls which support an above-water cross structure by means of four vertical surface-piercing struts; two canard fins are located near the hull bows and a cross stabilizing fin is located near the hull sterns. The SSP was constructed at the Coast Guard Shipyard at Curtis Bay, Md.
Dynamics of Eccentric Shafts Under Linearly Varying Tension Rotating in a Viscous Medium
Authors: Prodonoff V. , Michalopoulos C. D.
Published: November 2010

Using Euler-Bernoulli beam theory an investigation is made of the dynamic behavior of an eccentric vertical circular shaft rotating in viscous medium. The shaft is subjected to linearly-varying tension and has distributed mass and elasticity. The mass eccentricity is assumed to be a deterministic function of the axial coordinate. The solution is obtained by modal analysis. An example is considered wherein the shaft is simply supported at the top and vertically guided at the bottom. Steady-state deflections and bending stresses are computed for a particular eccentricity function over a range of speeds of rotation which includes a resonant frequency.
Examination of the Response of a Flexible Circular Rotor Subjected to Specified Gyroscopic Rates
Authors: Red W. E.
Published: November 2010

The natural and forced motion of a rotor configuration comprised of a constant thickness, annular plate fixed at the inner boundary to a rigid core and at the outer boundary to a symmetric, rigid rim is examined here. Natural modes and frequencies are determined for the rotor in the spin mode and numerical results are presented as a function of plate and rim parameters. The forced vibration response of the rotor subjected to constant spin and precession rates is examined with emphasis placed on understanding the boundary conditions imposed on the plate by the dynamic motion of the rim assumed to have a lateral degree of freedom and two rotational degrees of freedom about transverse axes. Free vibration of the rotor in a null gyroscopic state is also examined as a special case. Natural modes and frequencies are determined from the closed form solution obtainable for the governing equation of motion and presented as a function of plate and rim parameters.
The Investigation of the Enhancement Mechanisms of the Oxide Treatment on Cemented Carbide Tools
Authors: Naik S. K. , Suh N. P.
Published: November 2010

The mechanisms responsible for enhancement of the metal cutting properties of cemented carbide tools during oxide treatments are investigated. The reaction of individual phases present in cemented carbide tools with various oxides was analyzed experimentally under temperature-pressure conditions previously employed for the oxide treatment. The change in the surface structure and the formation of new phases were determined by means of X-ray diffraction, oxidation experiments, and thermodynamic analyses. The experimental results show that during the oxide treatment such carbides as TiC and ZrC, which are chemically more stable than WC, form on the surface of WC. It was also found that a small percentage of oxides mixed in the eutectic phase of Co-WC stabilizes the eutectic phase, thus preventing its adhesion to a solid piece of oxides.
Profile Characterization of Manufactured Surfaces Using Random Function Excursion Technique, Part 2: Application
Authors: Osman M. O. M. , Sankar T. S.
Published: November 2010

In Part 1 of this paper an analytical procedure based on the theory of random excursions was described to characterize the texture of a machined surface in terms of four new parameters. In this part a number of experimental results are presented to justify the validity of the proposed surface parameters. Surface measurements were carried out on ten differently machined surfaces using a specially equipped measuring device with a direct cable link to a hybrid computer. The theoretically computed surface parameters compare favorably with the measurements made on the actual surface profiles that were recorded experimentally. One of the advantages of the surface parameters presented in this paper is that they correspond directly to the mechanical properties of the machined component and hence can be used readily in specifications. Further, the results of this paper show that i) the sampling length is essentially a high-pass filter with geometrically defined characteristics, and ii) the crest and valley excursion parameters are adaptable for both “on-line” and “off-line” surface evaluation. The method presented is well-suited for application to computer-aided manufacturing without any special modifications. Based on this investigation, a proposal for a mechanical stylus system for “online” surface measurements is also made.
The Dispersion and Detectability of Sanitary Waste-Water Discharges From Navy Ships
Authors: Alig C. S. , van Hees W.
Published: November 2010

Assessing the impact of Navy shipboard sanitary waste discharges within the contiguous zone of the United States requires generation of data, not available so far, on the dispersion and fate of pollutants from shipboard sources. To generate data applicable to the 3–12-mi coastal zone, studies were conducted by the Naval Ship Research and Development Center using Naval facilities in the Norfolk, Va. area. Controlled releases were made of sanitary waste water and tracer dye mixtures. Dispersion of waste/dye patches was monitored through aerial reconnaissance, precise radio-navigational information, and seawater sample collection. It was demonstrated that pollution from controlled releases of sanitary waste can be detected above background concentrations for a brief span of time using conventional methods for determining effluent water quality (5-day biochemical oxygen demand, total suspended solids, ammonia-nitrogen, total acid-hydrolizable phosphate, coliform bacteria). A mathematical model for the dispersion of pollutants discharged from ships in the coastal zone was developed from these data. An assessment was then made of the concentration of pollutants after discharge from Navy ships during normal operation. Seawater samples were collected from the wakes of ships in transit and from the water around ships anchored for an amphibious operation in the coastal zone. It was determined that pollutants discharged from the transiting ships were not measurable above background concentrations, and only slight coliform bacteria population increases were detected in the amphibious operations area. These increases were still well within those prescribed as safe for bathing beaches and fisheries. Findings of this study specifically refer to the Navy ships and the geographic locations involved. They may be used for estimating effects of sanitary waste releases by non-Navy ships and in other areas.
Kineto-Elastodynamic Analysis of Slider-Crank Mechanism With a Flexibly Attached Slider
Authors: Chakraborty J. , Khare A. K.
Published: November 2010

Kineto-elastodynamics is the study of the motion of mechanisms considering the elasticity of the links. The mechanism examined in this paper is the eccentric slider-crank mechanism in which the slider mass is connected with the coupler by means of a linear spring. Equations for kineto-elastodynamic analysis of the mechanism have been derived, and an iterative scheme is suggested for the solution. Friction is assumed small, and the effect of damping, clearances in joints, and tolerances on links have been neglected. Some example problems are worked out, and the results are compared with the available ones.
Effects of Straining, Aging, and Stress-Relieving on Mechanical Properties of Steels for Arctic Service
Authors: Jesseman R. J. , Smith R. C.
Published: November 2010

The effects of straining, straining + aging, and straining + aging + stress-relieving on tensile and Charpy V-notch impact properties were determined for several candidate arctic pipe and fitting steels. Possible compositional and processing means to maintain high as-rolled energy levels in strained + aged pipe are discussed. Heat treatment of 787 and Mn-Mo-Cb, as would be necessary in fittings, increased toughness to the level that degradation due to straining + aging was readily accommodated even at −80°F (−62°C) test temperatures. For fittings designed to −20°F (−29°C) or higher service temperatures, Armco VNT-QT with restricted carbon content and sulfide shape control provided adequate toughness in the strained + aged condition. After stress-relieving, the impact properties improved enough to allow use of this grade at −80°F (−62°C).
The Twist of a Helically Buckled Casing
Authors: Mitchell R. F.
Published: November 2010

When a casing buckles in three dimensions, torques, as well as bending moments, are developed. Since well casing is joined with threaded collars, it is necessary to know the magnitude of the twist of the casing to evaluate the risk of buckling failure. In this work, the strain energy for a three-dimensionally buckled column is developed and the differential equations of buckling are derived and solved for helical buckling, buckling caused by an applied moment, and combined end loading and torque.
Simultaneous Coordination of Two Rigid Body Motions Through Infinitesimally Separated Positions
Authors: Siddhanty M. N. , Soni A. H.
Published: November 2010

A generalized mathematical approach is developed to guide two rigid bodies for simultaneous coordination of their infinitesimally separated positions. Mathematical relationships are developed to incorporate up to fourth-order derivatives while specifying infintesimally separated positions. The approach is demonstrated by considering an eight-link mechanism. It is shown that for a maximum of five precision positions of the two rigid bodies, a maximum of 1024 design solutions are possible.
Selective Precision Synthesis—A General Method of Optimization for Planar Mechanisms
Authors: Kramer S. N. , Sandor G. N.
Published: November 2010

A general method of optimal design of planar mechanisms is presented here called Selective Precision Synthesis (SPS for short), suitable for path, motion or function generation, with different arbitrary limits of accuracy at various discrete positions. It was found that the method yields fundamentally stable solutions: while in closed-form synthesis, small changes in prescribed values often result in very different solutions or no solutions at all, in SPS small perturbations in problem specifications often produce only small variations in the synthesized linkage dimensions. Such stability is rarely found in Burmester theory and other synthesis techniques. Applying nonlinear programming and introducing the dyadic construction of mechanisms, the SPS technique is applicable to the synthesis of most planar mechanisms including four-bar, five-bar, multi-loop, multi-degree of freedom and adjustable mechanisms. Also, dyadic construction simplifies the optimization process and renders the method readily manageable in interactive computer-aided design. The SPS digital computer programs for batch and tele-processing are made available to interested readers.
Material Removal by High-Pressure Liquid Jets at Ten Kilobars
Authors: Neusen K. F. , LaBrush E. C.
Published: November 2010

High-energy-density jets (0.75 × 106 hp/in.2) resulting from expanding liquid at extremely high pressures are capable of removing solid material from a wide variety of targets. Liquid jets with velocities up to 4000 fps (1220 mps) resulting from 10 kilobars of system pressure were used to penetrate aluminum, steel, rock, and plastic targets. A series of experiments was conducted to determine the effectiveness of materials removal as a function of nozzle-to-target distance and nozzle inlet pressure.
Analysis of In-Process Buffers for Multi-Input Manufacturing Systems
Authors: Law S. S. , Baxter R. J. , Massara G. M.
Published: November 2010

A model for multi-input manufacturing systems with in-process buffers is introduced based upon the concepts of system and subsystem reliability. A set of parameters is proposed for evaluating the effectiveness of individual buffers in relation to the total system. Through the technique of computer simulation an economic analysis of the use of buffers can be conducted by considering the reliability of facilities, downtime characteristic, work volume, labor cost, buffer cost, and buffer size limitations. The application of the model was demonstrated through an analysis conducted on an existing automotive Hood Assembly Line. The economic advantage and buffer size requirements as predicted by the manufacturing model are supported by the experience of plant management.
On the Extrusion in Superplastic Conditions
Authors: Alto A. , Giorleo G.
Published: November 2010

In this paper the range within which the slab method is accurate enough to calculate the extrusion pressure in superplastic condition has been determined. A realistic velocity field, supported by experimental evidence, has been adopted. A strain rate field has been evaluated and an appropriate constitutive equation has been introduced. The slab method and the upper bound approach, here developed, have then been used to study the superplastic extrusion through a conical die. A comparison of the two solutions thus obtained has been carried out. It has been found that in any case the curves obtained using the slab method run higher than those obtained using the upper-bound approach. The analysis developed may be used to determine the range within the slab method is accurate enough for engineering purposes.
Optimum Synthesis of Four-Bar and Offset Slider-Crank Planar and Spatial Mechanisms Using the Penalty Function Approach With Inequality and Equality Constraints
Authors: Alizade R. I. , Mohan Rao A. V. , Sandor G. N.
Published: November 2010

This paper discusses the application of the logarithmic penalty function for the optimal synthesis of function generating mechanisms satisfying inequality and equality constraints. A new method of deriving the transmission ratio and the objective function is also presented. Numerical examples are used to illustrate the optimization technique.
Sandwich Beams with Arbitrary Boundary Conditions
Authors: Krajcinovic Dusan
Published: November 2010

Presented is a practical and efficient method for the analysis of arbitrarily supported sandwich beams. Based on the previously derived set of governing variational equations, the present method utilizes familiar transfer matrix procedure. Final solutions for the displacement and stresses consist of two terms reflecting correspondingly the conventional (solid) beam bending and the cross-sectional distortion. The proposed method is illustrated in a few examples and the results are plotted for a wide range of geometric and material parameters.
A General Method for the Fatigue-Resistant Design of Mechanical Components—Part 2: Analytical
Authors: Vaughan D. T. , Mitchell L. D.
Published: November 2010

This paper develops the general analytical solution to the design of mechanical components under fatigue loading. Its only limitation is that the overloading lines must be a straight line on the σa−σm diagram. The designer is free to select his own failure theory for the material he intends to use as well as to select his own fatigue fracture criterion.
The Use of Coherence Techniques to Predict the Effect of Engine Operating Parameters on Diesel Engine Noise
Authors: Seybert A. F. , Crocker M. J.
Published: November 2010

A technique is presented in which the effects on noise of changing diesel engine operating parameters can be predicted. Traditionally, the effects have been determined by experiment. The technique presented in this paper utilizes experimentally determined frequency response functions between each cylinder pressure input and the engine noise. Once the frequency responses are measured, the engine noise can be calculated for an arbitrary cylinder pressure input. The effect of injection timing, engine load, and engine speed are predicted using cylinder pressure histories obtained from a single cylinder research engine. Experimental results are presented, showing good agreement with predicted data. It has been found that the measured frequency responses are independent of the cylinder pressure level. Also presented here is the multiple coherence between the cylinder pressures and the engine noise and the ordinary coherence between two typical cylinder pressures.
Parametric Influences on the Response of Structural Shells
Authors: Huffington N. J. , Wortman J. D.
Published: November 2010

The effects on structural response produced by variation of geometric, loading, and material property parameters have been investigated for the specific case of a fixed-ended cylinder subjected to a “frontal cosine” distribution of impulsive loading (although many qualitative results can be expected to apply to other cases). Responses were determined using the REPSIL code, which employs a finite difference method to solve the partial differential equations for large deflection, anelastic shell motions. Graphical representations of results in terms of six nondimensional quantities make it possible to obtain an overview of the influence of various system parameters on structural response and to draw certain conclusions regarding their relative importance. An empirical model based on REPSIL code data has been developed which permits rapid estimation of cylinder responses over a useful range of system parameters.
Minimum Exponential Cost Allocation of Sure-Fit Tolerances
Authors: Wilde D. , Prentice E.
Published: November 2010

The least cost allocation of sure-fit machine tolerances for Speckhart’s exponential cost model is solved in closed form, without numerical iteration, as a geometric program with zero degrees of difficulty. The results show the importance of an exponential cost sensitivity parameter defined as the “characteristic tolerance”. The theoretical minimum cost can be determined without specifying the corresponding tolerances. Specific minimum cost tolerances can be computed later in closed form if potential cost savings are significant.
An Analysis of Tool Life Based on Flank-Face Wear—Part 2: Comparison of Theory With Experimental Observations
Authors: Rubenstein C.
Published: November 2010

In Part 1 of this paper (Paper No. 75-WA/Prod-28) an analysis of tool life based on a flank-wear criterion was made based on the hypothesis that there exists a range of cutting conditions within which the temperature of the subsurface layers of the workpiece are virtually unaffected while the temperature of the subsurface layers of the tool rises considerably. In the present paper a large body of published experimental evidence is adduced and shown to be consistent with the results of the analysis and, thus, lends support to the hypothesis on which the analysis is based.
The Effect of Chucking Methods on Roundness Error in the Boring Process
Authors: Kahng C. H. , Lord H. W. , Davis T. L.
Published: November 2010

Curved-beam theory is used to obtain a theoretical model to describe deformations in a cylindrical workpiece during boring processes. Analytical expressions are obtained for roundness error due to two-, three-, and four-jaw chucks. Experiments are carried out and theory is compared with measured values of roundness errors for several combinations of material and geometric parameters, showing good agreement.
Dynamics of a Power Collector With Friction Dampers
Authors: Yoshida K. , Shimogo T.
Published: November 2010

Using the friction damper, the construction of power collector for a very high-speed railway will be considerably simplified. In this paper, the power collector with friction dampers is considered, and its dynamic characteristics are analyzed by the equivalent linearization technique. The main purpose of this paper is to investigate the effects of Coulomb friction forces on the mean squared value of contact force variation between a contactor and a rigid collecting rail with a randomly wavy surface. A numerical example is presented, and the optimal values of Coulomb friction forces which minimize the probability that the contact force becomes negative are found as a result.
Application of the Optimal Preview Control Theory to the Vibration Reduction of the Elastic Beam under Moving Load
Authors: Sasaki M. , Shimogo T.
Published: November 2010

In this paper, the vibration reduction problem of simply supported beam excited by distributed random moving load is investigated. The optimal transfer functions of preview filters, of which input is the future value of random load picked up at upstream position are obtained by solving the matrix Wiener-Hopf integral equations. The properties and control effects are shown numerically for two concrete examples. The results are compared with that of the system with passive elements in order to certify the effects of control. That is, the mean square deflection of beam corresponding to a certain constraint on the force transmitted by the controller is reduced in comparison with that of the system with passive elements, and it is further reduced with increasing of preview time to some extent.
Instantaneous Behavior of Lubricating Oil Supplied onto the Tooth Flanks and Its Influence on the Scoring Resistance of Spur Gears
Authors: Fujita K. , Obata F. , Matsuo K.
Published: November 2010

The correlation between the oil supply conditions, such as oil jet velocity, oil-nozzle position and its direction, and the scoring resistance of spur gear pair has been studied. The influence of the oil supply conditions on the instantaneous behaviors of the lubricating oil supplied onto the tooth flanks were brought to light by stroboscopic photographs. The scoring resistance was greatly affected by the oil supply conditions and the reasons were clarified by considering the instantaneous behaviors of lubricating oil. In order to have high scoring resistance, oil must be supplied over the whole working flank.
The Effect of Casing Wear on the Burst Strength of Casing—Part 2: Statistical Burst Strength of Worn and Unworn Casing Strings
Authors: Bradley W. B.
Published: November 2010

A theoretical analysis has been performed to determine the effects of wear on the burst strength of casing. Burst occurs either by a leakage at the casing joint or by a rupturing of the casing wall. The statistical nature of rupturing of casing is presented in this paper; joint leakage is discussed in a companion paper[1]. A method is presented in this paper that calculates the probable burst strength and confidence limits given the statistical distribution of casing properties; this method may be used for both worn and unworn casing. Using a limited set of casing properties, the analysis shows that the API methods for determining burst resistance may result in burst values that have very low probabilities of failure. In addition, the data used show that considerable casing wear can be tolerated before there is a significant probability of rupturing the casing wall under API calculated burst pressures.
Regenerative Drive for Subway Trains—Part 2: Overall System Model
Authors: Suokas L. A. , Flanagan R. C.
Published: November 2010

The external system (track, vehicle) for the regenerative drive study is modeled from actual construction drawings and performance specifications. A general duty cycle is constructed and found to compare within a few percent of actual measured data; furthermore, the duty cycle simulates all vehicle operational modes (“all out,” cruise, coast, brake). Vehicle dynamics are simulated using current railroad engineering practice; the equivalent mass of rotational elements (transmissions, rotors), about 16 percent of the vehicle curb mass, is accounted for in the accelerated state. The internal d.c. electric drive system is modeled using current industrial design practice; the technique of energy flow-through efficiencies facilitates the determination of vehicle station-station tractive requirements.
A Comprehensive Study of the Fixed Edge Bending Moments of Thin Rectangular Cantilever Plates Under Point Loading
Authors: Hageniers O. L. , North W. P. T.
Published: November 2010

An experimental program was performed to determine the effect of aspect ratio on point loaded cantilever plate bending moments. The experimental results are compared to theoretical values based on an extension of the work done on cantilever plate deflections by Szmelter, Sulikowski, and Lipinski [1]. The theory and experiment give excellent agreement over the range of aspect ratio studied. A series of curves is presented which gives the maximum plate bending moment as a function of aspect ratio and load position. These curves indicate the transition of plate bending moments from the cantilever beam case to the infinitely wide cantilever plate case.
Guide Vane Vibrations Caused by Wakes and Blower Noise—Part 1: The Vortex Degeneration in the Asymmetrical Wakes
Authors: Chen Y. N. , Baylac G. , Walther R.
Published: November 2010

The symmetrical wakes beyond a guide vane cascade consisting of curved and flat plates with blunt trailing edges were investigated as far as the excited dynamic stresses in the blades and the vortex Strouhal number are concerned. The results reveal that the flat plate is more liable to be damaged by the Karman vortex street than the curved plate. However, the vortex street can be effectively suppressed by giving the trailing edge an asymmetrical form. It will be shown that this suppression orginates from the difference of the vortex strengths in the two rows of the vortex street, causing the rapid degeneration of the vortices. This leads to the suppression of the reinforcement of the vortex strength by the lock-in because of lack of stable vortex region.
Predicting Natural Frequencies of a Hydrodynamically Lubricated Journal Bearing With Constant Oil Supply Pressure
Authors: Edwards D. C. , Khorzad N. , Edwards C. L.
Published: November 2010

The analytical and experimental investigations reported here deal with the natural frequencies and system behavior of a full journal bearing subjected to a small sinusoidal load superimposed on a large unidirectional static load. The analysis, verified by experimentation, shows that the bearing can be regarded as two independent second-order systems acting perpendicular to each other. The variable coefficients of the equations of motion cause the bearing to behave as an underdamped system for low values of static eccentricity ratio ε0, and as an overdamped system for intermediate values of ε0. The bearing tends to be unstable above a particular ε0. Further analysis is needed to determine the effects resulting from changing the oil inlet pressure.
Failure Analysis of a Redundant Reeving Hoist
Authors: Edmondson A. J.
Published: November 2010

An analysis is presented of a reeving arrangement suitable for the hoisting of critical materials requiring fail-safe criteria. The system consists of two independent wire ropes symmetrically threaded through the crown and lower blocks and reeved by a single takeup drum. The analysis provides for the load in each line of the wire rope remaining after failure of one rope occurs. The motion of the lower block and load are also provided for the variety of failure conditions considered. The analysis is useful to predict the effect of various design parameters on the integrity of system in the event of a single component failure.
A Singularity Approach to Circular Plates
Authors: Durocher L. L. , Palazotto A. N.
Published: November 2010

Axisymmetric circular plate solutions can be found in several references. A designer, in using the classical technique must, for the most part, consider loading functions not continuous over the plate, as would occur in ring supported structures, thus requiring a great deal of continuity matching. Attempts have been made to reduce the amount of tedious algebra required to match deflections, etc., by developing influence coefficients. Paul and associates recently presented a computer oriented approach, referred to as the integral method that further reduces the solution effort for discontinuous loadings. The authors observed that in all cases some form of indirect superposition must be incorporated. The present paper reviews a method for integrating the fourth-order plate equation in which each load function is represented by a singularity expression. In addition, discussion and comparisons are made with the previously mentioned techniques. Finally, application of the singularity function approach is directed toward complex loading conditions.
An Investigation of Computer Control of Machining Chatter
Authors: Subramanian T. L. , DeVries M. F. , Wu S. M.
Published: November 2010

Based on stochastic process modeling, a scheme has been developed for the detection and control of machining chatter. The range of the tool vibration signal is computed by a hybrid computer and compared with permissible limits to exercise automatic change of the speed and feed rate. The control scheme was evaluated for its adaptability and effectiveness by forcing a chatter condition and subjecting the process to computer control. The scheme is sensitive to process variables.
The Effects of Fiber Properties and Preparation on Trash Removal and Properties of Open-End Cotton Yarns
Authors: Vaughn E. A. , Rhodes J. A.
Published: November 2010

Cotton yarns of 36.9 Tex were spun at optimum twist levels on a Suessen Open-End Spin-tester at opening roller speeds of 5500 rpm, 7000 rpm, and 8500 rpm, and with waste-gap openings of 2.0 mm, 4.0 mm, and 5.5 mm from short and medium length cottons prepared with high and low gin cleaning. The spinning was performed at a constant rotor speed of 45,000 rpm and a static pressure in the spinning chamber equivalent to 7.9 × 10−5 Pa. Statistical analyses were performed on the data collected from physical tests performed on the yarn and on the amounts of trash extracted into the collection box and deposited in the rotor. These data are discussed along with a study of the nature of trash extracted into the collection box and deposited in the rotor. The results indicate that cotton fiber length was the most significant factor affecting yarn physical properties; yarns spun from short-length fibers were found to have better physical properties, less trash extracted into the collection box and deposited in the rotor, and fewer breakages than yarns spun from medium-length cottons. The degree of gin cleaning significantly affected only neps. More trash was extracted into the collection box and deposited in the rotor from cottons with a higher nonlint content after gin cleaning. Opening roller speed significantly affected single-end strength and thin places. As the opening roller speed increased, single-end strength increased, thin places decreased, the amount of trash extracted into the collection box decreased, and the amount of trash deposited into the rotor increased. The degree of waste-gap opening significantly affected single-end strength. At lower waste-gap openings, more trash was extracted into the collection box, and no significant effect on the amount of trash deposited in the rotor was found. The nature of trash extracted into the collection box was observed to be different from the trash deposited in the rotor.
Analysis of Feeding and Orienting Systems for Automatic Assembly—Part 1: Non-Vibratory Feeding Systems
Authors: Poli C. , Murch L. E.
Published: November 2010

The procedure used to obtain the general performance characteristics and design data of various nonvibratory feeders is described in detail for the case of the bladed-wheel hopper feeder. The results of the testing and analysis are summarized on data sheets similar to those contained in a handbook of feeding and orienting techniques for small parts that is currently being assembled at the University of Massachusetts.
Development of Economical Casting Process for NEMO-Type Acrylic Submersible Hulls
Authors: Stachiw J. D. , Lones J. J.
Published: November 2010

This paper describes an improved process for fabricating spherical acrylic plastic pressure hulls within close dimensional tolerances. The process consists of casting acrylic plastic hemispheres in a precision mold assembly, machining their equatorial edge and cutting polar penetrations, bonding them together with a cast-in-place equatorial joint, polishing their inner and outer surfaces, and installing an aluminum hatch and penetration plate. The cost of the improved process is approximately 50 percent less than that of the standard process, which consists of bonding together 12 thermoformed and machined spherical pentagonal shell sections. In addition, 90 percent fewer bonded joints are required, resulting in an order-of-magnitude improvement in optical qualities. A full-scale prototype with an outside diameter of 66.500 in. (168.9 cm) and an inside diameter of 58.000 in. (147.3 cm) has been constructed and shown to be acceptable for manned service to a depth of 2500 ft by hydrostatic testing under sustained loading at pressures of 900, 1350, 1800, and 4000 lb/in.2 (6.2, 9.3, 12.4, 27.6 MPa). Implosion occurred after 13 min of sustained loading at 4000 lb/in.2 (27.6 MPa) and 75°F (23.9°C) simulated depth of 9000 ft (2743 m).
Computerized Synthesis of Straight-Line Four-Bar Linkages From Inflection Circle Properties
Authors: Simo´n J. M.
Published: November 2010

The instantaneous property of the inflection circle corresponding to a four-bar linkage is used in the present paper to obtain points of the coupler with significant straight-line paths. These points are the interest points (IP) of the coupler, the existence and properties of which are demonstrated here using a digital computer to solve the developed equations that define the IP’s. This led us to propose a computerized trial and selection method of synthesizing straight-line four-bar linkages with new steps—the determination of IP’s and their paths—which will, we hope, shorten considerably the time it used to take to obtain the desired results of a particular problem.
A Study of Wall Ironing by the Finite Element Technique
Authors: Odell E. I.
Published: November 2010

Wall ironing has been analyzed using an elastic-plastic finite element technique. The effects that the ironing ring semi-cone angle and friction have on the maximum reduction ratio are studied in detail. Stress contours are given for a typical set of operating parameters. Several ram load/displacement curves are provided and compared with upper and lower bound loads.
An Analysis of Wave Convection of Rolling Bodies
Authors: Margolis D. , Hubbard M.
Published: November 2010

A bond graph model of wave convection of rolling bodies is developed. The governing non-linear state space equations are derived directly from the bond graph and solved numerically for various system parameters and driving frequencies. Results include the motion-time history of the uniform spherical bodies treated herein as they traverse the “singulation wave.” Critical speeds and frequencies are identified. These results typify the singulation process for various fruits and vegetables. It is shown that the moving belt can be closely approximated by a rigid sine wave translating at wave speed. This leads to the derivation of a simple energy based design criterion for critical frequencies. The inclusion of damping in the model lowers the critical frequencies and allows for accurate prediction of experimentally measured critical frequencies.
Feedback Control of Saw Blade Temperature With Induction Heating
Authors: Mote C. D. , Holo̸yen S.
Published: November 2010

Control of the axisymmetric temperature distribution in a circular saw has been shown to be an effective means of reducing blade vibrations. Theoretical and supporting experimental analyses of a basic induction heating coil design are presented here. An IR thermometer was designed to measure the blade temperature. Transient heating, transient cooling and steady state temperature experiments on circular saws were conducted both in the laboratory and in production. The true set point temperature was maintained to within 2 C.
Optimization of Cold Rolling by Nonlinear Programming
Authors: Rao S. S. , Kumar A.
Published: November 2010

The problem of determining the optimum design parameters of single pass and multipass cold strip rolling is considered. The problem is formulated and solved as a constrained nonlinear programming problem by considering the radius of rolls, and the front and back tensions as design variables. Two objectives, namely, the minimization of the deflection of rolls and the minimization of the power required for rolling, are considered in the case of single pass rolling. The minimization of the sum of deflections of all the rolls lying in series is considered as the objective in the case of tandem mill rolling. Constraints are placed on the induced stresses, neutral angle and the angle of bite. Example problems are presented to illustrate the efficiency of the optimization procedure presented.
A Numerical Method For Simultaneous Prediction of Metal Flow and Temperatures in Upset Forging of Rings
Authors: Nagpal V. , Lahoti G. D. , Altan T.
Published: November 2010

In this study, the interdependence between temperatures and metal flow during upset forging of rings has been investigated. An improved upper-bound analysis has been developed to predict metal flow and temperatures during ring compression. The metal flow and temperatures are considered to influence each other and are estimated at small discrete steps of deformation. Good correlation was found between predicted profiles of the bulged ring surfaces and the experimental results. The analysis and the experimental data show the effects of (a) friction on temperatures, (b) time of contact between the ring and the dies on temperatures and metal flow, and (c) ram speed upon metal flow and temperature. The simulation of the ring test, presented in this paper, is expected to allow a more precise interpretation of experimental results obtained in ring compression tests, especially in warm and hot deformation ranges.
Detection of Flaws in Railroad Wheels Using Acoustic Signatures
Authors: Nagy K. , Dousis D. A. , Finch R. D.
Published: November 2010

A system for automatic inspection of railroad wheels using acoustic signatures is proposed. There is a discussion of the types of defects which need to be found. The main components of a system are then outlined. It is concluded that impact is the best way to excite the wheel into vibration because of the rich spectrum of resonances generated. Detection of sound radiated into the air by a microphone is the best way to obtain the acoustic signature for finding cracks in the rim or plate, but flat spots or shattered rims are best detected with an accelerometer mounted on the rail. Methods of processing the signals from the detection transducers are then examined. Finally some preliminary laboratory and field tests of such systems are described.
Energy Requirements of the Rail Mode
Authors: Addie A. N. , Concannon B. T.
Published: November 2010

The results of computer simulations of railroad operations to determine the energy required to pull freight and passenger trains over mountainous and flat profiles is presented. The effect of variations in average speed, profile and types of freight cars, is also determined. The potential for recovering braking energy on mountainous grades and during passenger service with frequent stops is evaluated.
A Simple Dynamic Model For Simulating Draft-Gear Behavior In Rail-Car Impacts
Authors: Hsu T.-K. , Peters D. A.
Published: November 2010

A new, simple dynamic model is developed for use in simulating draft-gear behavior in rail-car impacts. The model is based on an analysis of the individual components inside several types of draft gears. The transition from kinetic to static friction during the impact is included. Comparisons with drop-hammer tests and full-scale impacts show good agreement with the experimental forces and deflections. In particular two very important phenomena are correctly simulated: 1) the rise in force just before maximum travel, and 2) the stick-slip-grab phenomenon during impact.
On the Measurement and Propagation of Flank Wear in Cutting Tools
Authors: Tseng M. M. , Noujaim R. A.
Published: November 2010

More than three hundred flank wear profiles of carbide cutting tools were digitized, stored and analyzed. It was found that different measures of the same wear zone, such as averages or maximums including or excluding the grooves, can significantly change the out-come of tool life studies. For a given test, all the measures used in this study correlate strongly with the true overall wear average during the entire tool life. However, no conversion factor independent of cutting conditions could be found for these measures. Propagation of tool wear profiles was also analyzed. It revealed that aside from the groove zones, the entire flank face shows equal significance in describing tool wear. Thus, when a wear sensor is physically embedded on the flank face for adaptive control purposes, any location between the grooves is as good as any other.
Drop-Size Distributions of Newtonian Liquid Sprays Produced by Fan-Jet Pressure Nozzles
Authors: Janna W. S. , John J. E. A.
Published: November 2010

The drop size distribution was measured by Newtonian liquid sprays produced by fan-jet pressure nozzles, operating in the pressure range 500 to nearly 3000 psig (3 450 to 20 680 kPa). The fluids used were water and a water-glycerin mixture. A collection device was constructed and droplets were captured on soot coated microscope slides. Subsequent sizing of the impacted particles with a microscope yielded drop size distribution data of accumulated volume per cent versus diameter. An experimental analysis was performed to relate the nozzle wall shear to the volume median diameter of the spray distribution. A linear correlation was found to exist on a semilog graph; for the Newtonian liquid sprays, it was determined that the volume median diameter could be predicted with: Dd=+8.5183−1.1113logτρQμσ
Dust-Trash Removal by the SRRC Tuft-To-Yarn Processing System
Authors: Kotter J. I. , Thibodeaux D. P.
Published: November 2010

A detailed study of the quality and quantity of fine dust and trash removed from cotton fibers by the SRRC Tuft-to-Yarn system in its various stages of processing is presented. Collection of fine dust and trash was accomplished by isokinetic sampling from the respective pneumatic systems of the mini-condensers and OE spinners. An impaction-type precutter permitted classifying dust particles from the sampled air into two fractions, one greater than 15 μm aerodynamic diameter and the other less. Three grades of cotton, SM, SLM, and SGO, were used in the study which also included a determination of the cleaning efficiency of each of the processing stages, based on trash content and amounts removed as measured by the Shirley analyzer. A comparison is made between the proportion of fine dust removed by the system and the residues of dust/trash found in conventional OE spinner rotors.