bluuebunny/crossref_metadata_2025 huggingface dataset:
Power Analysis of Cold Strip Rolling
Authors: Avitzur B.
Published: December 2011

In a previous paper criteria for maximum possible reduction were developed. A simple procedure for the experimental determination of the coefficient of friction was introduced. In this paper a solution for the efficiency is presented. A term called “Minimum Required Reduction,” which was briefly mentioned earlier [2], is discussed in detail. The results of experimental work for the determination of the coefficient of friction are described. A simple expression for the separation force is given. Finally, a procedure for optimum operation is suggested. The controllable variables are pointed out and the steps in the choice of the optimum conditions are described.
1961 Review of Metal Processing Literature
Authors: Pentland W. , Campbell J. S. , Kobayashi S. , Galimberti J. M. , Hahn Robert S. , Weller E. J. , Crawford J. H. , Pickrell A. L. , Lascoe O. D. , Roubik Joseph , Vaughn R. L. , Boulger Francis W. , Tarasov L. P. , Backer W. R. , Cook N. H. , Krabacker E. J. , Sluhan Clyde A. , Moyer R. G. , Smith P. A.
Published: December 2011

By the members of the Literature Review Committee of the Metal Processing Research Activity of ASME: W. Pentland, Cornell University, Chairman; E. G. Thomsen, University of California, Metal Cutting Analysis; E. J. Weller, General Electric Company, Metal Cutting Practice; F. W. Boulger, Battelle Memorial Institute, Plastic Working of Metals; R. S. Hahn, The Heald Machine Company, Grinding; C. A. Sluhan, Master Chemical Corporation, Metalworking Fluids. The purpose of these reviews is to appraise the important new knowledge on metalworking appearing in the published literature of the past year and present a digest of the significant new information through ASME as a contribution to improvement of metalworking practices throughout industry.
Bearings for Vacuum Operation—Retainer Material and Design
Authors: Evans Harold E. , Flatley Thomas W.
Published: December 2011

This report describes the initial phase of an investigation of the high-speed operation of miniature ball bearings, with metallic film lubrication, in a vacuum environment. Phase I of this study was conducted to determine the most promising retainer material and design for use in a general study of the effectiveness of various metallic coatings as lubricants. Fully machined retainers of five different materials, with all balls and races of gold plated 440C stainless steel, were tested. Both pure gold plating and gold with additives were investigated. Size R2-5 bearings were run without external loading at a nominal motor speed of 10,000 rpm and the goal is a bearing life of 1000 hours in an ambient pressure of 10−7 torr. The results show that: (1) Thin metallic films as lubricants show real promise when used in a vacuum environment; (2) pure gold plating is not as effective as the plating with additives; (3) fully machined retainers provide good performance, and the use of relatively hard retainer materials significantly extends the useful life of the bearings; and (4) the bearing failures tended to be catastrophic rather than gradual, making the prediction of the onset of failure difficult. A special multiport oil-free vacuum system designed and built for this program proved extremely effective in achieving a vacuum of 10−7 torr, and in permitting the operation of seven individual tests at one time.
Effect of Tool Joints on Passages of Plane Longitudinal and Torsional Waves Along a Drill Pipe
Authors: Bradbury R. E. , Wilhoit J. C.
Published: December 2011

The effect of tool joints on the passage of plane longitudinal and torsional waves along a drill pipe was studied. An approximate solution to the governing equations of motion was found, and an idealized tool joint constructed. Calculations were made for the effect of the idealized joint on an example drill string. The results showed that tool joints had negligible effect for exciting frequencies of the same order as common rotary speeds and the drill pipe could be taken as a uniform pipe with negligible error.
Drill String Vibrations Due to Intermittent Contact of Bit Teeth
Authors: Paslay P. R. , Bogy D. B.
Published: December 2011

An analysis of the longitudinal forces and the resulting longitudinal motions of an idealized drill string is presented. The only external force excitation considered occurs at the bit and is due to the intermittent contact of the teeth with the bottom of the hole. Attention has been restricted to the following two salient possibilities: 1 - Excitation at the bit may develop oscillating forces at the bit with amplitudes of the same order of magnitude as those of the bit load. 2 - Appreciable bit load variation may be detected by instruments which measure the motion of the drill string near its top. The first possibility is important if maximum penetration rate is to be achieved, and the second possibility is important in implementing practical measurement of the phenomenon. From the results of the specific example considered in this report, it is concluded that possibilities 1 and 2 may occur in sufficient magnitude to be influential, but experimental data on the actual bit motion and the damping will be required to evaluate the effect. The analysis is presented in such form that the influence of the various parts of the system can easily be evaluated.
The Optimization of Damping of Four Configurations of a Vibrating Uniform Beam
Authors: Henney Alex , Raney J. P.
Published: December 2011

Approximate analytical expressions for optimum damping for four configurations of forcing and damping a uniform beam were evaluated and the displacement responses for optimum damping values obtained from these expressions were calculated by a digital computer. It was found that the responses were accurately optimized. The sensitivity of maximum displacement response to deviation from optimum damping was investigated, but no analytical expressions relating change to deviation were obtained. An empirical formula, based upon consideration of the response of the beam as a single-degree-of-freedom system, was shown to be a good approximation of results obtained from the computer response curves. The four configurations investigated were relatively insensitive to changes in damping from optimum.
Stability of the High-Speed Journal Bearing Under Steady Load: 2—The Compressible Film
Authors: Cheng H. S. , Trumpler P. R.
Published: December 2011

The governing equations for the dynamical system of a self-acting gas-lubricated journal bearing are formulated. An approximate solution for the equilibrium position of the journal center is obtained by use of Galerkin’s method. The equilibrium solution shows close agreement with the exact numerical computer solution obtained by Elrod. The stability of the equilibrium solution is investigated by solving the linearized equations on an analog computer. The solution of the set of linearized equations shows that there exists a threshold speed of instability for each equilibrium position. The value of this threshold speed is presented in a stability chart. In addition, approximate particular solutions for the nonlinear dynamical equations are obtained by use of the analog computer. The results are shown as trajectories of the journal center when it is displaced arbitrarily from the equilibrium position.
The Influence of Physical Properties on Machinability
Authors: Henkin Alexander , Datsko Joseph
Published: December 2011

This paper is the result of an analytical and experimental study of the effect of the physical properties of a material on its machinability. The physical properties studied were: the total stress-strain relations; the hardness; the microstructure; the abrasiveness; the thermal properties. A variety of ferrous and nonferrous materials were selected with a large range of the physical properties. A relationship is derived by means of which it is possible to calculate the culling speed for a given tool life from the physical properties of the work material.
Mechanics of Metal Cutting for a Material of Variable Flow Stress
Authors: Oxley P. L. B.
Published: December 2011

A new analysis is presented in which the variable flow stress property of the work material is taken into account. It is shown that changes in the so-called angle of tool-chip interface friction can result from changes in the shear zone mechanism and, for example, the paradoxical behavior observed when cutting with carbon tetrachloride as a “lubricant” can be accounted for in this way. It is concluded that if actual predictions are to be made about the cutting process, i.e., without first making cutting tests, then the angle of tool-chip interface friction cannot be accepted as given information. The analysis is extended to cutting with a variable depth of cut, and in agreement with experiment it is predicted that, with all other cutting conditions the same, the cutting force will be less for an increasing depth of cut than for a decreasing depth of cut.
The Mechanism of Chip Curl and Its Importance in Metal Cutting
Authors: Cook N. H. , Jhaveri P. , Nayak N.
Published: December 2011

In this paper, the mechanism of chip curl is studied, and the importance of chip curl on such practical consequences as tool life and surface finish is noted. A new set of ideas concerning the cause-effect relationship between chip-curl and various metal cutting parameters is set forth.
Criticism of Radioactive Tool-Life Testing
Authors: Cook N. H. , Lang A. B.
Published: December 2011

Tungsten carbide and high-speed-steel lathe tool wear tests, carried out by conventional means and by radioisotope techniques, are compared. When the irradiated tool is used to cut under only one set of conditions, good correlation is obtained between the two methods. When the irradiated tool is used under a variety of cutting conditions, correlation is poor. If a single tool is used under different cutting conditions, it is doubtful if differences of less than 2:1 are significant.
Influence of Channel Curvature on Flow, Pressure Distribution, and Power Requirements of Screw Pumps and Melt Extruders
Authors: Booy M. L.
Published: December 2011

The influence of channel curvature on flow through screw pumps and melt extruders is derived for infinite channel aspect ratios. Flow rate and horsepower relations for flow of Newtonian liquids are given as functions of design parameters. The results of this cylindrical theory are compared with those of conventional theories. Curvature factors converting the equations of the flat plate theory to those of the cylindrical theory are shown. Pressure distributions in screw pump channel are analyzed.
An Upper-Bound Approach to Cold-Strip Rolling
Authors: Avitzur Betzalel
Published: December 2011

The operation of cold-strip rolling is treated under the assumption of “Mises” material. A lower upper bound on energy consumption is computed. Then, assuming constant shear between strip and rolls, an approximate value of the actual energy is determined. Another value is arrived at by assuming Coulomb friction between strip and rolls. An efficiency factor is determined through the ratio of required to ideal energy, the former being the combined energy of deformation and friction losses on the strip surface. The total deformation energy includes the internal strain energy (ideal energy) associated with an assumed strain field and the energy along the surfaces of velocity discontinuities. The roll torque, minimum required friction (or maximum possible reduction), and efficiency are determined as functions of the other process variables. Results are presented graphically and as mathematical expressions. This study is a direct sequel to an earlier paper [6], in which velocity discontinuities were disregarded.
Transmission Matrices for Vibration and Their Relation to Admittance and Impedance
Authors: Rubin S.
Published: December 2011

The character of transmission matrices is explored for application to the vibration of multiterminal elements which obey reciprocity. The concept of a rectangular transmission matrix is introduced and its limitations discussed. Interrelationships among the transmission, admittance, and impedance matrix descriptions of an element are presented. The approach is applied to a system consisting of a source, a transmission element, and a load, with a multiplicity of interconnections between the three elements. The results apply to linear elements from any field (e.g., structural, electrical, acoustic) and also to elements of mixed type (e.g., electromechanical). The Nomenclature and examples apply specifically to structural elements.
Tool-Life Testing by Response Surface Methodology—Part 2
Authors: Wu S. M.
Published: December 2011

This paper is a continuation of a previous paper in which the basic philosophy of response surface methodology has been explained and a first-order tool-life-predicting equation has been developed. This part of the paper illustrates the development of a second-order tool-life-predicting equation in 18 and 24 tests. It was found that the second-order effect did not show statistical significance within the cutting ranges of this project; however, the second-order effect of cutting speed has been found important by the study of residuals. If only one independent variable is investigated, a minimal number of tests can be used to find a second-order equation. Examples of designs in three, five, and six tests are illustrated.
An Analysis of Centerless Grinding
Authors: Gurney J. P.
Published: December 2011

Centerless grinding has grown enormously in importance in the last 30 years, until today it is a standard production technique. Instead of the work being supported between centers, as in the older cylindrical grinding, it is supported by means of contact with the grinding wheel, the regulating wheel, and the work blade. In this paper, the methods of analysis already developed and used to examine other machining processes [1, 2] are extended and applied to centerless grinding. Unfortunately, a centerless grinding machine was not available, so it was not possible to apply the analysis to an actual case. The problem was, however, set up on an analog computer, and the effect of changes in various parameters on the stability evaluated. In the light of the results obtained from the computer study the reasons for a number of features of machine-shop practice, evolved by trial and error, can be explained, giving every reason to believe that the analysis is a realistic one. In addition to the stability of the process, the transient behavior inevitably associated with infeed grinding is considered.
Report of Committee RR-6 Survey: Progress in Railway Mechanical Engineering, 1962–1963
Authors: Meier D. R. , Bateson N. E. , Lich R. L.
Published: December 2011

This paper contains the annual report of the ASME Survey Committee RR-6. Developments in Railway Mechanical Engineering from September 1, 1962–September 1, 1963, pertaining to cars and locomotives are discussed. A review is given of locomotive development activities. Diesel and electric locomotives, passenger freight cars, and transit and suburban cars introduced in North America, Europe, and Asia are described and pictured.
Plastic Analysis of Radial Outlets From Spherical Pressure Vessels
Authors: Lind N. C.
Published: December 2011

A method is described whereby the limit pressure may be determined for a radial juncture of a cylindrical vessel and a spherical vessel, assuming quasi-rigid plastic behavior. The limit pressure may for mild-steel vessels be interpreted as the pressure causing extensive local deformation at the juncture under static loading conditions.
Buckling of Drill Pipe in an Inclined Hole
Authors: Bogy D. B. , Paslay P. R.
Published: December 2011

The buckling of drill pipe in the vertical plane for the case of an inclined hole is studied. This is accomplished by performing a stability analysis of a simply supported column lying in compression on a rigid inclined plane in the presence of a gravity field. The lateral displacement of the column is restricted to be perpendicular to the plane. According to the results of an approximate analysis it is found that the system becomes unstable under the above conditions only if the lateral variational displacements are finite. The derived stability equation is verified for a particular case by a simple experiment. The results of this analysis can be used to determine the “crookedness” of a hole which, under specified conditions, will induce instability.
Performance of Gears Under High Loads and Low Velocities
Authors: Cress H. A. , Fitzgerald E. , Mark D. G.
Published: December 2011

To obtain information concerning the ability of conventional parallel-shaft gears to transmit motion smoothly at low velocities under high load, experiments were conducted on a single commercial gear mesh about the same size as the last stage proposed for a radio telescope drive. Two torque levels of 130,000 and 197,000 lb-in. were used. The largest amplitude of angular disturbance which was measured was less than 10 arc sec, while the average disturbance was about one arc sec at the low speed shaft. The smooth performance of the industrial-quality gear trains eliminated the expense of special designing. In similar applications where smooth motion is a requirement, components of good reliability and comparatively ready availability can be specified with confidence.
Pulse-Tube Refrigeration
Authors: Gifford W. E. , Longsworth R. C.
Published: December 2011

A very simple effect makes it possible to construct very low temperature refrigerators without the use of low temperature moving parts or the Joule-Thomson effect. The effect, which occurs in many places and is frequently ignored, is described in detail, along with means for using it to build refrigerators capable of achieving low temperatures. A description of experimental models and test results is also included. A temperature 218 deg F below room temperature has been achieved.
Controlled-Force Grinding—A New Technique for Precision Internal Grinding
Authors: Hahn Robert S.
Published: December 2011

The causes of random-size variations and random-taper variations in feed-rate grinding are described and related to stock variations and wheel-sharpness variations. A new technique, controlled-force grinding, is presented which eliminates errors resulting from variable elastic deflections. An analysis is made of the rounding-up dynamics of the controlled-force system and a critical workspeed is found which must be exceeded in order to have a rounding-up action. A study is also made of the stability of the system using the Nyquist criterion.
Analysis of Wire Drawing and Extrusion Through Conical Dies of Large Cone Angle
Authors: Avitzur Betzalel
Published: December 2011

This work is a direct extension of reference [3]. There the problem was treated with the assumption that the cone angle was small. Here this limitation exists no more. The operations of wire drawing and extrusion through conical dies are treated on the assumption that “Mises” material is formed. An upper-bound solution is obtained for the drawing stress in wire drawing and for the pushing stress in extrusion. The effect of each of the process variables on these forces is presented graphically. The process variables are: the cone half-angle (α), initial (Ri) and final (Rf) wire radius, material yield limit (σ0) under uniaxial load, back pull (σxb) and front pull (σxf), coefficient of friction (μ) or shear factor (m), die land (L), exit velocity (vf), and entrance velocity (vi). On the assumption that the maximum front tension cannot exceed the yield limit of the material under uniaxial tension, a solution is obtained for maximum possible reduction in wire drawing. An analogous assumption, i.e., that the absolute value of the pushing stress also cannot exceed the yield value, gives a criterion for maximum possible reduction in extrusion.
An Investigation of Grinding Wheel Cutting Edges
Authors: Tsuwa H.
Published: December 2011

A new apparatus for microscopic observation and tracing of cutting edges of a wheel has been developed. The use of this apparatus allows us to visually witness the behavior of abrasive grains during the grinding operation. A phase-contrast microscope, as well as an electron microscope has been used with the new apparatus in this investigation. A method of calculating effective grain spacing to show distribution of cutting edges, as well as the cutting edge ratio to known worn conditions of grains has been completed. These aforementioned values for various grinding wheels have been studied in grinding operations and the changing aspects of them have been noted. Through these experiments, we have had helpful suggestions about grinding mechanisms; there is no self-dressing action of grains in the usual grinding work; sliding of the cutting edges takes place in the grinding, and wear of the grinding is increased by this action.
Fluid Mechanics of Zero-G Propellant Transfer in Spacecraft Propulsion Systems
Authors: Gluck D. F. , Gille J. P.
Published: December 2011

The basic requirement of a transfer system for storable propellants is to provide propellant in sufficient quantity to assure proper engine operation. The main propulsion systems of advanced spacecraft will make many restarts after long coast periods during which the propellant is in a weightless state. Various vehicle motions, such as rotational maneuvers, may result in dislocation of propellant from the region of the outlet of un-baffled tanks. In this paper a promising method of propellant relocation, settling by means of an induced gravitational field, is considered. Small axially directed rockets are used to generate a low g-field for settling the propellant. The value of the acceleration that must be exceeded to assure propellant flow from top to bottom of the tanks (the critical acceleration) has been determined by a numerical solution of the interface equation. This acceleration is exceeded by several orders of magnitude for practical settling rocket systems. The fluid mechanics of the ensuing “settling” flow and the subsequent rebound or “geysering” is discussed and a criterion for settling time is suggested. These results were obtained through scaled experiments conducted at 1-g conditions.
Experiments on Room-Temperature Nernst-Ettingshausen Refrigerators
Authors: Harman T. C. , Honig J. M. , Fischler S. , Paladino A. E. , Button M. J.
Published: December 2011

Cooling experiments with a (transverse) Nernst-Ettingshausen NE refrigerator using properly oriented and shaped single crystals of pure bismuth are described. By cooling the hot junction Th of the specially designed refrigerator with flowing water, temperatures as low as 191 K were achieved at the cold surface while maintaining the warm surface at 279 K. Measurements were carried out for various values of the electrical current up to 85 amp and various values of the magnetic field up to 90 kilogauss. The experimental results were found to be essentially in accord with the theory concerning the operating characteristics of shaped devices. Since the temperature difference occurred across a 5-mm distance, an average temperature gradient of 170 deg K/cm was calculated.
1963 Review of Metal Processing Literature
Authors: von Turkovich B. F. , Roubik J. R. , Gilbert W. W. , Ham Inyon , Oxford C. J. , Pickrell A. L. , Wilson G. F. , Boulger F. W. , Hahn R. S. , Krabacker E. J. , Cook N. H. , Tarasov L. P. , Backer W. R. , Smith P. A. , Sluhan C. A. , Downing C. E. , Wennberg J. L. , Neidzwiedzki A. , Weller E. J.
Published: December 2011

By members of the Literature Review Committee of the ASME Metal Processing Research Activity: J. L. Wennberg, General Electric Company, Chairman; B. F. von Turkovich, University of Illinois, Metal Cutting Analysis; J. R. Roubik, Kearney & Trecker Corp., Metal Cutting Practice; F. W. Boulger, Battelle Memorial Institute of Technology, Plastic Working of Metals; R. S. Hahn, the Heald Machine Co., Grinding; P. A. Smith, Massachusetts Institute of Technology, Metalworking Fluids. The purpose of this review is to appraise the important contributions to the knowledge of material processing appearing in the published literature and to present a digest of this new knowledge through the Society as a contribution to the improvement of material processing practices throughout industry.
Drill String Vibration Attenuation and Its Effect on a Surface Oscillator Drilling System
Authors: Angona F. A.
Published: December 2011

The attenuation of acoustic vibrations was determined by measuring the decay of stress pulses induced in a drilling string. The relationship of attenuation to frequency was obtained by a Fourier analysis of the pulse after it had traveled various distances in the drill string. The attenuation coefficient was found to be sufficiently low to warrant consideration of drilling methods in which vibratory motion is transmitted from a surface vibrator to the bit by the drill string.
Strength of Threaded Joints for Steel Pipe
Authors: Clinedinst W. O.
Published: December 2011

This paper covers the analytical development of strength formulas for fracture and jumpout and determination of material constants from 162 joint tests. These formulas were adopted by API at the June, 1963, Standardization Conference, and are the basis for new joint strength values for API casing contained in the eighth edition of API Bulletin 5-C-2 on Performance Properties of Casing and Tubing. These formulas are entirely new and offer, for the first time, a rational explanation of joint failure.
Analysis of the Motion of Deep-Water Drill Strings—Part 1: Forced Lateral Motion
Authors: Graham R. D. , Frost M. A. , Wilhoit J. C.
Published: December 2011

An equation of motion for a drill string, considering elastic, dynamic, and drag forces, is derived. This equation is then applied to two types of drill-string behavior; i.e., a beam having constant axial tension and a perfectly flexible cable under variable tension. A drill string is then synthesized by subdivision into short beam sections at the top and bottom, joined by a flexible cable in the center. The lateral deflection of the drill string is obtained by joining the beam and cable solutions, subject to boundary conditions at each junction. The drill string is considered built-in at the ocean floor and is displaced harmonically at the surface by the ship. An example is discussed and results are compared with experimentally measured values. The effect of roll will be considered in a subsequent paper; as the governing equations have been linearized, these solutions may be superimposed.
Analytical Kinematic Synthesis by Finite Displacements
Authors: Wilson J. T.
Published: December 2011

One method to synthesize plane mechanisms is by graphically constructing the circle point and center curves for a prescribed motion. This paper presents an analytic method for determining these curves in Cartesian coordinates for both plane and space mechanisms. The solutions to these curves are not transcendental and may be programmed on a computer.
Higher Path-Curvature Analysis in Plane Kinematics
Authors: Freudenstein F.
Published: December 2011

Classical kinematics furnishes us with powerful techniques for the determination of the motion characteristics of a rigid body, or “plane,” or link. The present analysis is concerned more with the motion characteristics of the path generated by a point on a link, rather than with the link as a whole. For four infinitesimal displacements, it is shown that the locus of all points on a link with a prescribed ratio of path-evolute curvature to path curvature is a higher algebraic curve, the “quartic of derivative curvature.” For five infinitesimal displacements, five points on a moving link can in general be found having five-point contact with an arbitrary, prescribed curve. For circular motion, these results reduce to the classical theories of Burmester and Mueller. Equations have been derived for the first and second rates of change of path curvature in terms of the evolutes to the path. The results are applicable to the kinematic analysis and synthesis of mechanisms and are illustrated, specifically, for the generation of involute, parabolic, and elliptic arcs.
Solutions to the Vector Tetrahedron Equation
Authors: Chace Milton A.
Published: December 2011

A set of nine closed-form solutions are presented to the single, three-dimensional vector tetrahedron equation, sum of vectors equals zero. The set represents all possible combinations of unknown spherical coordinates among the vectors, assuming the coordinates are functionally independent. Optimum use is made of symmetry. The solutions are interpretable and can be evaluated reliably by digital computer in milliseconds. They have been successfully applied to position determination of many three-dimensional mechanisms.
On Polygonal Action in Roller Chain Drives
Authors: Bouillon Gratien , Tordion George V.
Published: December 2011

Numerical analyses of the kinematics of an idealized model, together with experimental measurements of periodic fluctuations in the angular displacement ratio, are used to supplement existing knowledge of polygonal action in roller chain drives. The paper presents a number of drives for which harmonic analyses coefficients of the theoretical angular displacement-error function have been computed.
Fracture Resistance in Line Pipe
Authors: McClure G. M. , Duffy A. R. , Eiber R. J.
Published: December 2011

The program of research on line pipe under the sponsorship of the A.G.A. Pipeline Research Committee is a comprehensive effort to investigate the important properties of pipe used in gas transmission. Several different phases are involved in this project, ranging from fundamental laboratory studies to fracture-behavior experiments on large-diameter pipe. This paper discusses the full-scale experimental parts of the program in which the fracture toughness of line pipe is being studied. Some of the factors that influence full-scale fracture behavior are discussed—material properties, fracture speed, temperature, wall thickness, nominal stress level, and type of backfill. Laboratory fracture tests that are being run and correlated with full-scale behavior are also described.
The Role of Stress Concentration in the Fatigue of Delrin
Authors: Wolf L. J. , Diboll W. B.
Published: December 2011

Specimens of Delrin Acetal Resin with different stress-concentration factors were fatigue-tested in tension. Cyclic heat generation affects the strength of the part. Conventional stress-concentration factors may be used for Delrin, provided that the temperature is kept low enough, either through low loads or good heat transfer.
Rheological Aspect of Tool Wear in Machining Graphite
Authors: Takeyama H.
Published: December 2011

When machining materials such as graphite and plastics, a very interesting phenomenon can be observed in the manner of the tool wear. The faster the speed, the lower the rate of tool wear. The experimental analysis gives an acceptable ground for the proposition that the phenomenon can be attributed to the rheological behavior in wear.
Optimum Diameter and Position of a Fly Cutter for Milling 0.45 C Steel, 195 BhN and 0.4 C Steel, 167 BhN at Light Cuts
Authors: Hoshi T. , Okushima K.
Published: December 2011

Selection of cutter diameter and position of the cutter with reference to the work piece was studied to control the face-milling tool tip failure by fracture. The majority of the tests consisted of studies of the effect of angle of engagement and angle of disengagement on fractures at low and high cutting speeds. The result shows that the angle of disengagement is more critical than the angle of engagement. Favorable cutter diameters and positions based on empirical data are recommended to prevent fractures occurring at low and high cutting speeds. This report suggests that steel can be face-milled with titanium carbide and aluminum oxide tools using optimum setups as suggested by this study.
Theory of Self-Excited Machine-Tool Chatter: Contribution to Machine-Tool Chatter Research—1
Authors: Merritt H. E.
Published: December 2011

Self-excited chatter, an instability of the cutting process in combination with the machine structure, is a basic performance limitation of a machine tool. A theory is developed which permits calculation of borderlines of stability for a structure having n-degrees of freedom and assuming no dynamics in the cutting process. Harmonic solutions of the system characteristic equation are found using a special chart, and the resulting data are used to plot a stability chart. However, an infinite number of such stability charts exists for a given machine because the structure dynamics vary with cutting-force orientation. This fact makes a simpler index of chatter performance desirable. A simple stability criterion is proposed which states that the directional cutting stiffness must be less than one half the minimum directional dynamic stiffness of the structure for each force orientation to assure chatter-free performance at all spindle speeds. Thus chatter-free performance can be fundamentally identified with adequate structural dynamic stiffness for all cutting-force orientations. Such a broad requirement for dynamic stiffness is difficult to meet in the design stage since structural characteristics are not easily predicted and controlled. Machine testing with continual improvements in the structure to increase dynamic stiffness is currently the best way to combat chatter.
Hydrostatic Extrusion
Authors: Avitzur B.
Published: December 2011

The process of hydrostatic extrusion, where the liquid-surrounded billet is pushed through a die by means of liquid pressure instead of a ram, is analyzed. Expressions are provided giving the following: (a) The required pressure as a function of the other process variables. (b) The most suitable cone angle minimizing the required pressure. (c) The capacity of existing equipment. The present study is an extension of a previous study [12] of flow through converging conical dies.
On the Propagation of Finite Disturbances in Bars of Rubberlike Materials
Authors: Nowinski J. L.
Published: December 2011

The existing theory of propagation of waves of finite amplitude is applied to rubberlike materials using a rigorous finite deformation theory of elasticity. Mooney-Rivlin and Neo-Hookean bodies are investigated in more detail, and explicit solutions are given for the speed of propagation, the particle velocity, and the conditions at the shock front. A numerical example concerning the Neo-Hookean body is given.
Some Effects of Geometry, Orientation, and Acceleration on Pool Film Boiling of Organic Fluids
Authors: Heath C. A. , Costello C. P.
Published: December 2011

Ethanol, pentane, and Freon-113 were tested for atmospheric pressure, saturated film-boiling characteristics. Turbulent waves arise close to the bottom of vertical platinum plates and the data become identical to those obtained with horizontal plates, verifying an earlier contention by Y. P. Chang. The equation of Berenson fits the data for both horizontal and vertical heaters fairly well if modified for geometry, and the equation also correctly predicts the effect of acceleration on film-boiling heat-transfer coefficients. At high temperature differences, Berenson’s equation for the heat-transfer coefficient is slightly conservative, which is qualitatively predictable by analyzing the departures of the actual system from the idealized model of Berenson.
Quasi-Steady Flow and Thrust in Accelerating Nozzles and Channels
Authors: Wu J. C. , Pottsepp L.
Published: December 2011

Internal flows of compressible fluids in nozzles and constant-area channels subjected to constant axial acceleration or gravitation are examined in detail. It is found that the effect of nozzle acceleration or deceleration is analogous to that of perturbing the cross-section area of nonaccelerating nozzle. Acceleration enchances the effect of nozzle divergency and deceleration reduces it. Sonic speed is reached upstream of an accelerating nozzle throat and downstream of a decelerating nozzle. Integral relations of various flow properties are derived and methods for obtaining numerical solutions are developed. Using a power-series expansion in terms of a dimensionless number related to the rate of acceleration, a formula is derived for the estimation of impulse function increment due to acceleration. For constant-area channels, it is found that the flow Mach number always changes away for unity, whereas in a decelerating channel, the Mach number always changes toward unity. Continuous transitions between supersonic and subsonic flows are not possible.
Theoretical and Experimental Band Saw Vibrations
Authors: Mote C. D. , Naguleswaran S.
Published: December 2011

The frequencies of particular, periodic band-saw, transverse-vibration solutions, denoted here as natural frequencies, are determined both theoretically and experimentally. Three simple, approximate natural-frequency analyses are presented; the approximate natural frequencies are compared to the exact and to experimental values for a particular table-model band saw.
Analysis of Pressure Pulsations in Reciprocating Compressor Piping Systems
Authors: Grover S. S.
Published: December 2011

This paper deals with pulsations in pressure and flow in the reciprocating compressor and connected piping system. A model is presented that describes the excitation at the compressor and the propagation of the pulsations in the interconnected piping. It has been adapted to digital computations to predict the pulse magnitudes in reciprocating compressor piping systems and to assess measures for their control. Predicted results have been compared with field test data and with simplified limiting condition results. A discussion of its practical application is included.
Flueric Operation on Pressure Signals
Authors: Katz Silas , Roffman Gary
Published: December 2011

A three-stage, jet-deflection-type, proportional fluid amplifier with feedback is used to demonstrate some mathematical and control operations. The operations performed on pressure signals are summing, scaling, proportional plus integral, and proportional plus derivative. The test results show that these devices are already suitable for applications where high accuracy is not required.
On the Lateral Stability and Control of the Automobile as Influenced by the Dynamics of the Steering System
Authors: Segel Leonard
Published: December 2011

Measurements of the directional response of an automobile to torque inputs applied at the steering wheel are compared with predictions yielded by a five-degree-of-freedom model of a four-wheeled, pneumatic-tired vehicle. This comparison demonstrates that the directional control and stability of the “free-control” automobile is satisfactorily characterized by the addition of a quasilinear representation of a steering system (i.e., a mechanism having two degrees of freedom with Coulomb friction introduced as the single nonlinear element) to a linear three-degree-of-freedom representation of the “fixed-control” automobile. Use is made of the experimentally substantiated five-degree-of-freedom mathematical model to study the relationship between automotive design parameters and the response and stability in each of the four natural modes of motion that exist for the free-control vehicle.
High-Frequency Fatigue of Metals and Their Cavitation-Damage Resistance
Authors: Thiruvengadam A.
Published: December 2011

In order to verify the strain-rate effects on the correlation between strain energy of metals and their cavitation-damage resistance, high-frequency fatigue tests at 14.2 kcs were conducted using a magnetostriction oscillator. Utilizing Morrow’s theory, it has been shown that fatigue at this frequency can be quantitatively represented if a 15 percent reduction in static strain-hardening factor is made. This result shows that the strain-rate effects are relatively small (for the metals investigated) when plastic-strain energy is used as a criterion. Another result revealed by this study is the influence of corrosion on high-frequency fatigue and cavitation-damage resistance. Present experiments show that fatigue strength can be reduced significantly for SAE 1020 steel in 3 percent NaCl solution even at high frequencies, thus confirming earlier speculations on this aspect.
The Reciprocal Theorem for Harmonic Oscillations of an Elastic, Isotropic Medium
Authors: Sann Robert I. , Shaffer Bernard W.
Published: December 2011

Using the formulation of continuum mechanics, a dynamic reciprocal theorem is derived for sinusoidal motion of an elastic medium. It is found that, exactly as in the static case, the work of the forces of State 1 acting through the displacements of State 2, equals the work of the forces of State 2 acting through the displacements of State 1. A simple example is given, which illustrates the application of the reciprocal theorem to the analysis of forced vibrations of beams.
Structural Analysis of an Arteriole by the Direct Stiffness Method
Authors: Gerstenkorn G. F. , Kobayashi A. S. , Wiederhielm C. A. , Rushmer R. F.
Published: December 2011

The direct stiffness method is used to analyze the structural response of the cross section of an arteriole which is both heterogeneous and nonlinear in terms of structural response. A typical segment of the cross section is represented by an assembly of triangular elements. The stiffness matrix and strain-displacement relationships are then derived in terms of polar coordinates for a triangular plate element. Viscoelasticity is included in this structural analysis by using a piecewise linear approach. Stress-time and displacement-time data are presented for two typical cross sections of the arteriole. These results reveal special properties of a heterogeneous structure which is undergoing viscoelastic deformations.
The Strength of Diamond
Authors: Hull E. H. , Malloy G. T.
Published: December 2011

Practical, handbook-type information on the strength of diamond is scarce and scattered. This paper reports data taken on the breaking strength of good quality, natural diamond octahedra. Average values are 1,261,000 psi in compression, 43,400 psi in torsion, yielding the exceptional ratio, compression divided by torsion, of 29.
Flow Characteristics Through Conical Converging Dies
Authors: Avitzur B.
Published: December 2011

A velocity field is considered to describe flow through conical dies. The expected distorted grid pattern is studied. Strain and strain rate fields are analyzed. Effective strain and effective strain rate distributions and their averages are defined. Application to processes like drawing extrusion and hydrostatic extrusion is discussed. Analysis is compared with experimental published data.
The Effects of Membrane Properties and Structural Parameters on the Non-Minimum Phase Behavior of the PEM Fuel Cell Humidification System
Authors: Hall John F. , Mecklenborg Christine A. , Hearn Clay S. , Chen Dongmei
Published: December 2011

The water vapor transfer across a Nafion® membrane exhibits an undesired non-minimum phase behavior. This paper will show that even in the disturbance-to-output loop, the non-minimum phase zero adversely affects the feedback controller design because of the coupling effect between the disturbance-to-output and the input-to-output loops. The non-minimum phase zero location is influenced by the channel plate structure and the membrane material property. The structural parameters examined in this research include channel plate dimensions and heat transfer coefficients. The membrane properties studied include membrane vapor transfer properties described in the Arrhenius’ equation. A governing equation to link the non-minimum phase zero and the parameters is developed in this paper. This equation shows that the non-minimum phase zero arises from the competing heat and mass transfer dynamics, and is determined by the structural parameters and membrane properties. A sensitivity study is presented and shows that structural and material property optimization can be used with the control system design to mitigate the non-minimum phase behavior in the PEM fuel cell humidification system.
Submerged Jet Impingement Boiling of Water Under Subatmospheric Conditions
Authors: Cardenas Ruander , Narayanan Vinod
Published: December 2011

An experimental study of jet impingement boiling is presented for water under saturated and subcooled conditions. Unique to this study is the documentation of boiling curves of a submerged water jet under subatmospheric conditions. Data are reported at a fixed nondimensional nozzle-to-surface distance of H/dj = 6 and for a fixed surface-to-nozzle diameter ratio, dsurf/dj, of 23.8. Saturated jet impingement experiments are performed at three subatmospheric pool pressures of 0.176 bar, 0.276 bar, and 0.478 bar with corresponding saturation temperatures of 57.3 °C, 67.2 °C, and 80.2 °C. At each pressure, jet impingement boiling at varying Reynolds numbers are characterized and compared with pool boiling heat transfer. The effect of surface roughness and fluid subcooling is studied at the lowest pressure of 0.176 bar. Boiling curves indicate a strong dependence of heat flux on jet Reynolds number in the partially developed nucleate boiling region but only a weak dependence in the fully developed nucleate boiling region. At a fixed wall superheat, fluid subcooling is found to shift the boiling curve to the left thereby enhancing heat transfer performance. Critical heat flux is found to increase with increases in pressure, surface roughness, and Reynolds number.
Large-Scale Vortex Generation Modeling
Authors: Booker Christopher D. , Zhang Xin , Chernyshenko Sergei I.
Published: December 2011

Methods of modeling vortex generation in computational fluid dynamics calculations without meshing the vortex generating device are investigated. In this way, the effect of adding vortices to existing flows can be assessed without the need to modify the computational grid; this can represent a significant saving. Previous work in this area has focused on boundary layer control. This study looks at larger scale applications, such as using vortices for force augmentation or directing flow. Two different approaches are used: modeling the vortex generator and modeling just the vortex alone. For the former, an existing method, which acts to align the flow with the vortex generator by adding a forcing term to the governing equations, is tested, but found to be unsuitable for use on this scale. The other approach is to add specified vortex velocity profiles, allowing the introduction of arbitrary vortices. A new version is developed to add continuous 3D velocity distributions in regions where desired vortices are to be created. It is implemented using several different forms of forcing. After basic testing, all methods are applied in a practical engineering case using a commercial solver.