bluuebunny/crossref_metadata_2025 huggingface dataset:
A General Formulation of the Milling Process Equation: Contribution to Machine Tool Chatter Research—5
Authors: Sridhar R. , Hohn R. E. , Long G. W.
Published: December 2011

In the cutting process, forces are induced at each of the cutter teeth in contact with the workpiece, and these forces in turn excite the machine tool structure. Due to the inherent feedback which exists between the cutting forces and the structure deflection, there are conditions under which this system becomes unstable. When this occurs, a condition of self-excited chatter exists. In the theory of self-excited chatter for single point tools wherein the tool is continuously in contact with the workpiece, the system can be described by a time-invariant equation, and has been rather fully developed. However, the milling process cannot be described in this manner. It is characterized by a multitooth cutter, and the cutting process itself is interrupted. Also, the direction of the cutting forces generated by each tooth does not remain constant with respect to the machine tool structure as for turning operations, but changes direction as a function of cutter position. In this paper, more complete description of the milling process is formulated. The resulting equation is a general nth order vector-matrix linear equation with periodic coefficients and a transport lag. Or equally, it is a linear differential-difference equation with time-varying coefficients. This equation is then expressed as n-first order equations (state variable form), consistent with current literature and in a form compatible for digital computer analysis.
A Stability Algorithm for the General Milling Process: Contribution to Machine Tool Chatter Research—7
Authors: Sridhar R. , Hohn R. E. , Long G. W.
Published: December 2011

In this paper, a method of stability analysis for the general milling process is given. The milling operation is described by a linear differential-difference equation with periodic coefficients. An algorithm which can be used in conjunction with the digital computer is developed as a means of analytically determining the stability of this equation. This algorithm will permit the determination of the stability boundaries in the space of controllable parameters associated with a cutting operation and allows more realistic models for milling to be studied than have been attempted up to the present time. The technique is used to predict the stability in an example of a milling operation.
A Theoretical Method for the Analysis of Metal-Working Problems
Authors: Shabaik A. H. , Thomsen E. G.
Published: December 2011

Theoretical and experimental flow fields of several extrusion ratios of lead extruded in plane strain are compared. The two methods given were derived from the equations describing the mechanics of the process. The differential equation in the flow function was used to obtain the flow lines. Excellent agreement was found when both the flow lines and the velocity components were compared with those obtained experimentally. The experimental and theoretical solutions which were obtained are both unique and complete.
Plastic Deformation of Copper and Steel in Hot Extrusion Through Conical Dies
Authors: Altan T. , Kobayashi S. , DePierre V. , Pierce C. M.
Published: December 2011

A method of observing flow lines during metal forming was applied to the conical die extrusions of oxygen-free high-conductivity copper at 800 deg F and of SAE 1018 steel at 1800 deg F, under various extrusion conditions. The experiments were carried out at the Metals Processing Laboratory, Wright-Patterson Air Force Base. The deformation characteristics based on experimentally obtained flow lines were examined in terms of the velocity components and the effective strain distribution, and the effects of materials, ram speed, die cone angles, and reductions on the deformation characteristics were discussed. For calculating velocity components and effective strains, the computer programs developed at the University of California, Berkeley, were used with slight modifications.
The Influence of Redundant Work When Drawing Rods Through Conical Dies
Authors: Caddell R. M. , Atkins A. G.
Published: December 2011

Values of the redundant work factor in rod drawing were determined experimentally for four metals over a wide range of variables; none of the metals were strain hardened prior to drawing. The method of superposition of stress-strain curves before and after drawing was used, and an expression for the redundant work factor was found to be related to the strain hardening characteristics of the metal being drawn. Use of this factor was made to predict certain mechanical properties of the drawn metals; these agreed quite well with the values measured experimentally.
The Kinematics of Contacting Surfaces
Authors: Cowie A.
Published: December 2011

Tests on contacting cylindrical rollers are used in estimating the surface durability of gear teeth. There is a great lack of uniformity in the methods used to describe the contact states on rollers and on gears. In addition, no formulas are available for describing the contact state on cams with flat-faced followers. This paper presents a general method of describing the contact state on any pair of bodies in direct contact and shows how the same method can be used for gears, cams, and rollers.
Design Criteria for Generalized High Strain
Authors: Kardos G.
Published: December 2011

Recent developments in solid state physics are used to derive a technique for determining the response of metals to dynamic loads. Design formulas are derived which predict the response of a metal to general short time loadings, in terms of maximum stress, pulse duration, and pulse form. The necessary material parameters, three, to establish high strain rates response are identified. Experimental evidence verifying the derived criteria is presented.
Design of Space Mechanisms for Function Generation
Authors: Suh C. H.
Published: December 2011

A generalized matrix for the description of finite functional displacement based on kinematic inversion technique in three dimensions is developed and applied to the synthesis of RSSR mechanism for function generation and also the analysis of functional performance of the synthesized mechanisms.
Thermal Buckling and Frictional Effects on Postbuckling Behavior of Sealed Electric Motor Liners
Authors: Cloud R. L. , Dittmar J. H.
Published: December 2011

Thermal buckling and postbuckling behavior of cylindrical liners for canned electric motors have been investigated. It is shown that if an initial circumferential eccentricity exists, a short axial buckle at the eccentricity will be the preferred form of buckling. The temperature required to buckle the can has been found in terms of the can geometry, material, and initial eccentricity. The postbuckling behavior is governed by frictional forces which change the buckling from an abrupt to a gradual process. Deformations are dependent on the postbuckling temperature.
Water Electrolysis: Prospect for the Future
Authors: Wydeven T. , Johnson R. W.
Published: December 2011

A survey of oxygen generators for spacecraft based on water electrolysis is presented. The water electrolysis cells surveyed are predominantly prototype units including both liquid and vapor feed cells. Cell design, operational performance, gas purity, and problems encountered during testing are discussed. Suggestions are given as to where future research might be concentrated in order to solve some of the more general problems associated with water electrolysis.
Theoretical Investigation of Heat Pipes Operating at Low Vapor Pressures
Authors: Levy E. K.
Published: December 2011

A one-dimensional analysis of a compressible vapor flowing within the evaporator section of a heat pipe is presented. Comparisons between the theoretical results and existing heat pipe data show that the presence of gasdynamic choking can limit the heat transfer capacity of a heat pipe operating at sufficiently low vapor pressures.
Film Cooling With Normal Injection Into a Supersonic Flow
Authors: Goldstein R. J. , Eckert E. R. G. , Wilson D. J.
Published: December 2011

An experimental study of film cooling with subsonic gas injection into a mainstream with a Mach number of 2.90 is reported. Air, used as both the mainstream and secondary fluids, is injected normal to the surface of a flat plate through a short porous section into a two-dimensional turbulent boundary layer. The secondary fluid enters the boundary layer with a mass velocity which ranges from 0.0085 to 0.0223 of the free-stream value. The adiabatic wall temperatures are presented as the film-cooling effectiveness. The results of the present study, when the proper choice is made for the reference state used to account for fluid property variations across the high-speed boundary layer, are in good agreement with previous investigations in incompressible flows.
Mass Transfer Cooling on a Porous Flat Plate in Carbon-Dioxide and Air Streams
Authors: Laganelli A. L. , Hartnett J. P.
Published: December 2011

Heat transfer results are reported for a transpiration cooled porous flat plate placed in a stream of air and in a stream of CO2. The tests were performed at a Mach number of 1.96 over a range of effective length Reynolds number, from 5 million to 9.1 million, when CO2 was used as the free stream gas. A Mach number of 2.53 for an effective length Reynolds number range of 5.3 million to 8.3 million was characteristic when the free stream gas was air. The heat transfer data were normalized and presented as the ratio of the Stanton number to the no-blowing Stanton value (St/St0) as a function of the dimensionless transpiration rate F/St0. The recovery factor data were also normalized and presented as the ratio of r/r0 as a function of the transpiration rate F. The results for both the air and the CO2 free stream flows showed a reduction in heat transfer with increasing transpiration rate, using air and CO2 as the injectant gases. The measured recovery factor and the normalized recovery factor also decreased with increasing transpiration for the reported gas combinations. It was found that Rubesin’s air theory adequately predicts all of the heat transfer results including those obtained in CO2 atmospheres within the reported Mach number range. Also, the empirical theories which predict recovery factor results for air free streams can be used for air or CO2 injection into a CO2 free stream gas.
Vapor-Liquid Separation at Supersonic Velocities
Authors: Garrett R. L. , Oehlschlager W. K. , Tomich J. F.
Published: December 2011

When a gas mixture at high pressure is expanded to a lower pressure, autorefrigeration often causes some of the heavier components to liquefy. This paper presents a new method for separating components of a gas stream by incorporating isentropic expansion and subsequent inertial separation of the dispersed liquid phase formed. Supersonic velocity of the stream is attained upon expansion and is maintained during the vapor-liquid separation process. Liquid droplets are ejected through the permeable outer wall of a curved flow channel, effecting the phase separation. Pressure is recoverable in part, if the supersonic stream is decelerated in a diffuser after removal of the liquid phase. Design considerations of such a process and major parameters for obtaining and maintaining stable supersonic channel flow are discussed. An experimental unit designed for an 1800 psi natural gas feed stream has been tested and preliminary results are summarized.
Buckling and Lateral Vibration of Drill Pipe
Authors: Huang Tseng , Dareing D. W.
Published: December 2011

Critical buckling loads and natural frequencies of lateral vibration modes are determined for a long vertical pipe, suspended in a fluid, simply supported at the top and vertically guided at the bottom. The data show the effect of thrust force at the pipe’s lower end on the magnitude of the natural frequencies. The differential equation contains a term with a variable coefficient and is solved by use of a power series.
Prediction of Low-Cycle Fatigue Life of Specimens With Fabrication Flaws
Authors: Pickett A. G.
Published: December 2011

A modification of the notch stress procedure for fatigue-life analysis is presented. The importance of considering the mechanics of the specimen and the effects of the notch on specimen mechanics is illustrated by example. The procedure is applied to correlate the results of small specimen tests with large weld defect specimen tests. The significance of crack-initiation life and crack-propagation life and the dependence of these portions of total fatigue life on specimen geometry and loading is developed.
Elastic Stability of Circular Tubes of Circumferentially Variable Thickness Under External Pressure
Authors: Nordgren R. P. , Murphey C. E.
Published: December 2011

The effect of circumferential variation in wall thickness on the elastic stability of long, thin-walled, circular tubes under external pressure is investigated both theoretically and experimentally. The theoretical critical pressure for instability is deduced from an extension of Levy’s classical stability analysis. Experimental values of critical pressure are reported for tubes with flats milled on the outside surface. Both numerical and experimental results indicate a transition from symmetric to asymmetric deformation at instability as the minimum wall thickness decreases.
Stress Solution for an Infinite Plate Containing Two Arbitrary Circular Holes Under Equal Biaxial Stresses
Authors: Salerno V. L. , Mahoney J. B.
Published: December 2011

A method of successive approximations utilizing analytic stress functions of the complex variable z, in the manner of the Schwartz Alternating Method, has been used to obtain the solution of the stress distribution around two circular holes of unequal radii in an equal biaxial stress field of an infinite plate. The stress functions up to a third approximation are obtained in all detail for one numerical example and a chart for a wide range of hole and distance parameters is developed for practical use. It is believed that this basic solution for two holes is a preliminary attempt toward the solution of stress concentration problems in the perforated components in pressure vessels in the area of reactor structures. It is also believed that this solution may be used to obtain solutions to more complicated hole patterns.
In-Plane Bending of Curved Circular Tubes
Authors: Cheng D. H. , Thailer H. J.
Published: December 2011

A general solution is presented for a thin, curved circular tube under in-plane bending. It includes the solution given by Clark and Reissner as a particular case in which the ratio of the radius of the tube to the radius of its center line is very small. The series expansions satisfy the equilibrium equation for any radius ratio while the compatibility condition is guaranteed by minimizing the complementary energy. The minimization is achieved in the manner of Raileigh-Ritz whereas the evaluation of integrals are facilitated by the use of binomial expansion. Numerical results correlate well with the experimental data. The solution is more rapidly convergent as compared to the existing analytical methods.
Longitudinal and Angular Drill-String Vibrations With Damping
Authors: Dareing D. W. , Livesay B. J.
Published: December 2011

This paper discusses longitudinal and angular drill-string vibrations and supporting field measurements taken with a special downhole recording instrument. Computer programs based on the theory are used to calculate longitudinal and angular vibrations (caused by periodic bit motions) along the drill string; field measurements made during actual drilling operations are used to check computer calculations. The main difference between this and other theory on the same problem is the inclusion of friction, which acts along the length of a drill string and impedes longitudinal and angular vibrations. For the sake of simplicity, the effect of different types of friction, such as fluid, rubbing, and material, which act along the string, is approximated by the effect produced by viscous friction. This approximation is generally accepted and appears to give adequate results for the drill-string vibration problem.
Railway Overhead Contact Systems, Catenary-Pantograph Dynamics for Power Collection at High Speeds
Authors: Levy S. , Bain J. A. , Leclerc E. J.
Published: December 2011

A program has been prepared for the GE-625 computer in Fortran IV language to compute the dynamic behavior of a catenary and pantograph for railroad cars moving at constant velocity. The catenary is considered to consist of two wires joined by elastic droppers at arbitrary locations. The upper catenary wire is in turn supported by elastic towers at arbitrary locations. Account is taken of: Tension and mass in each wire; wire sag; damping of the wires; springing between shoe and wire; springing and damping between shoe and pantograph frame; damping of the pantograph frame to the railway car; lifting of the wire away from the shoe; and stops in the pantograph to limit motion between shoe and pantograph frame. Up to eight arbitrarily spaced pantographs can be included, with as many as sixty droppers and ten towers. Force at up to ten droppers can be printed as a function of time. The additional output is catenary deflection and forces and deflections of the pantographs. Results are presented for some interesting variations of the system constants.
Discussion: “A Method for Relating Test Track Data to the Real World” (Wiebe, D., 1968, J. Eng. Ind., 90, pp. 727–735, and Henderson, K. A., and Johnson, J., 1968, J. Eng. Ind., 90, pp. 717–724)
Authors: Luebke R. W.
Published: December 2011

The purpose of this discussion is (a) to develop a method by which test track data can be related directly to any railroad’s rock and roll problem, and (b) to provide a means for objectively evaluating the railroad’s requirements for rock and roll control devices.
Balancing of High Speed Machinery
Authors: Han Chi-Yeh
Published: December 2011

An analytical method for optimal balancing of the shaking forces and the shaking moments of force of any plane mechanism driven by a constant speed shaft is developed. The optimal values of phase angle and mass moment of the balance weight on the driving shaft are ascertained, such that the variation of load on the machine supports due to shaking forces and shaking moments of force will be a mininum through a complete revolution of the driving shaft. Using a digital computer, this method is applicable to complicated mechanical systems; an illustrative example follows the analysis.
Review of Materials Processing Literature—1965
Authors: Quackenbush L. J. , von Turkovich B. F. , Roubik J. R. , Crawford J. H. , Gilbert W. W. , Ham Inyong , Toney L. B. , Pickrell A. L. , Vaughn R. L. , Wilson G. F. , Farmer D. A. , Mueller J. A. , Nakayama K. , Price J. E. , Tarasov L. P. , Smith P. A. , Sluhan C. A. , Boulger F. W.
Published: December 2011

The purpose of this paper is to provide a review of significant technical literature published about materials processing in 1965. Such new knowledge is presented through the Society as a contribution to the improvement of materials processing practices throughout industry.
Torsional Vibrations in the Shafts of Linkage Mechanisms
Authors: Meyer zur Capellen W.
Published: December 2011

Torsional vibrations in the input and output shafts of mechanisms are described by Hill’s differential equations. In this paper the equations are given and computer solutions, approximations, and the results of experiments are compared.
Optimum Design of Curve-Generating Linkages With Inequality Constraints
Authors: Fox R. L. , Willmert K. D.
Published: December 2011

The problem of synthesizing a four-bar linkage is presented as a mathematical programming problem. The objective is to synthesize a four-bar linkage whose coupler point will generate, as closely as possible, a given curve, and whose crank rotations will be as close as possible to desired values. Constraints are imposed on the design variables which force the result to be a four-bar linkage, limit the forces and torques within the linkage, restrict the location of the pivot points, limit the lengths of the links, and so on. The solution is found using an iterative technique with the aid of a digital computer. Several examples are presented which demonstrate the effectiveness of this approach. They include generation of a straight line, a figure eight, and a portion of a circular arc (previously investigated using a method developed by Freudenstein and Sandor). The work on this problem area is still in progress and there remain a number of open questions and unexplored alternatives.
Predicting Bearing Performance of Filled Teflon TFE Resins
Authors: Lewis R. B.
Published: December 2011

The wear rates of filled compositions of Teflon can be reliably predicted using an experimentally determined wear factor if the bearing pressure, velocity, temperature, and geometry are known. New evidence confirms the wear rates are directly proportional to pressure and velocity in both the mild wear regime and the severe wear regime, although the wear factors are much higher in the severe regime. The transition from mild to severe wear is pressure and surface temperature dependent and coincides with (but is not adequately described by) PV limit. An application factor is proposed to relate bearing surface temperatures to PV and geometry.
Multivariable Studies of Nonwoven Fabrics
Authors: Winchester S. C. , Whitwell J. C.
Published: December 2011

The performance characteristics of nonwoven fabrics have been studied as a function of fiber properties, binder properties, and web construction. The particular type of non-woven selected for study was a web of random-laid base fibers in which randomly placed thermoplastic fibers provide the bonds. The responses studied were those related to rupture, elastic, and handle (aesthetic) properties. Fourteen variables were investigated: Base fiber linear density, base fiber staple length, amount of crimp in base fiber, post-yield extension of base fiber, type of binder, linear density of binder, staple length of binder, binder concentration, mass per unit area of nonwoven, amount of needle looming, number of laminations per web weight, pressure of bonding, temperature of bonding, and time of bonding. The performance characteristics measured as a function of these variables were maximum tenacity at dry and wet conditions, elongation at dry and wet conditions, tear strength, abrasion resistance, elastic modulus at dry and wet conditions, proportional limit at dry and wet conditions, crease recovery, bending length, flexural rigidity, bending modulus, bulk density, and air permeability. Crimp, linear density, and staple length of the base fiber influence rupture, elastic, and handle properties, as expected. Binder properties, other than type, have no effect due to the destruction of the fiber in the bonding process. Bonding conditions, particularly pressure and temperature, are extremely influential in all types of properties. These variables govern the effectiveness of the bonds. Concentration of binder is extremely important to all types of responses since it governs the number and distribution of bonds. Needle looming affects only rupture properties.
The Free Vibrations of Stiffened Drill Strings With Static Curvature
Authors: Frohrib D. A. , Plunkett R.
Published: December 2011

The natural frequencies of lateral vibration of a long drill string in static tension under its own weight are primarily the same as those of the equivalent catenary. These frequencies and the mode shapes are affected to a certain extent by the bending stiffness and to a greater extent by the static deflection curve due to lateral deflection of the bottom end. In this paper, the governing equations are derived and general solutions are given in an asymptotic expansion with the bending stiffness as the parameter. Specific numerical results are given in dimensionless form for the first three natural frequencies for a very wide range of horizontal tension and several appropriate values of bending stiffness for zero vertical static force at the bottom.
Static Bending Stresses in Catenaries and Drill Strings
Authors: Plunkett R.
Published: December 2011

A limp string loaded only by its own weight has a nonlinear differential equation which may be integrated as two first-order equations with arc length parameter. If bending stiffness is also included, such a procedure fails since the order of the differential equation increases by two. In this paper it is shown that relatively small stiffness causes an effect only in boundary regions near the end supports and that the deviation from the catenary can be found as a rapidly converging series. The bending stress and the correction to the sag and length can be found from these correction terms. This result is used to find the bending stress caused in cables by vertical suspenders and in drill pipe by end fixity or moment.
Pipe Stresses Induced in Laying Offshore Pipeline
Authors: Wilhoit J. C. , Merwin J. E.
Published: December 2011

Part 1: No reverse curvature. Part 1 of this paper considers the bending stresses induced in the unsupported length of pipe as it feeds off of the supporting stinger with no change in sign of curvature. The effect of various parameters on the stresses is treated. Part 2: Reverse curvature. Part 2 considers the case which occurs when the pipeline tips over the end of the stinger and undergoes reversed curvature before coming back into contact with the stinger.
The Mechanical Behavior of Anisotropic Sedimentary Rocks
Authors: McLamore R. , Gray K. E.
Published: December 2011

The compressive strength as a function of confining pressure and sample orientation was determined for three anisotropic sedimentary rocks (slate and two types of shales). The samples were tested over a confining pressure range of 0 to 40,000 psi, with pore pressure held constant at atmospheric pressure. The orientation of the plane of anisotropy (bedding or cleavage plane) was varied between 0 and 90 deg relative to the axial load. The test results indicate that anisotropic sedimentary materials fail or deform by shear along the bedding plane, shear across the bedding plane, plastic flow along the bedding plane, or internal buckling depending upon the orientation and/or the initial stress state. The strength data gathered were compared to three basic failure theories for anisotropic materials: (a) Walsh-Brace modification of Griffith’s theory; (b) single plane of weakness theory; (c) variable coefficient of friction and cohesive strength theory. It was found that over certain pressure ranges and orientations all three theories fit the experimental data. On the basis of experimental data an empirical relationship was proposed to be used in conjunction with the variable coefficient of friction and cohesive strength theory. This modified theory produced a good fit of the experimental data over all orientations.
The Determination of Equilibrium Configurations of Spring-Restrained Mechanisms Using (4 × 4) Matrix Methods
Authors: Livermore D. F.
Published: December 2011

A spring-restrained, multiple-loop, multiple-degree-of-freedom kinematic chain will normally have one or more stable equilibrium configurations when steady external loads are applied to it. The “kinematic equivalent” of a vehicle and its suspension linkages is a common example of such a system. Changes in external loading due to cornering, braking, and so on, can produce important changes in the equilibrium configuration of the suspension. This paper presents a general method for determining the equilibrium configurations of spring-restrained, kinematic chains under the action of steady external loading. The iterative (4 × 4) matrix method of displacement analysis, previously developed for single-loop chains, is extended to complex chains and is used to determine the displacement and velocity information required for equilibrium analyses. The final results are general computer programs which will determine displacement and/or equilibrium configurations for simple or complex mechanism systems wherein the applied force systems may be considered conservative.
Acceleration Analysis of Spatial Linkages Using Axodes and the Instantaneous Screw Axis
Authors: Skreiner M.
Published: December 2011

The application of recent techniques developed in the geometry and the kinematics of instantaneous spatial motion generated by a pair of axodes, and the relative spatial motion of three rigid bodies using the instantaneous screw axis is demonstrated in an analysis of the Bennett Mechanism. Explicit equations which are well suited to machine calculations yield input-output information, the location and the properties of the instantaneous screw axis, the characteristic properties of the axodes, the velocity and the acceleration of a general point in the moving link, and the position of the center of acceleration in the moving link.
General Systematization and Unified Calculation of Five and Four-Bar Plane Basic Mechanisms
Authors: Bogdan R. C. , Huncher T. V.
Published: December 2011

This paper is based on the use of complex harmonic series in the examination of plane mechanisms. Certain general considerations are established for the kinematic solving of binary structural groups (Assur groups). Further, a general systematization of the mechanisms is made by associating the dyads to two driving links (which can have rotatory or translatory joints or a combination of them). The solutions obtained in the general study of dyads are also presented, under the specific conditions of five or four-bar mechanisms. Simplified forms are obtained. The method leads to a unified calculation for various types of five-bar mechanisms, and also for four-bar mechanisms as a particular case of the former. A numerical example for a case of a five-bar mechanism is also included. It is shown that the application of the method of complex harmonic series facilitates the examination of five-bar mechanisms.
Analog Simulation of Rigid Link Mechanisms
Authors: Timm R. F.
Published: December 2011

This paper describes a procedure for simulating rigid link mechanisms on an analog computer. The computer circuit enables one to record all kinematic variables, i.e., displacements, velocities, and accelerations, for any point on the mechanism using conventional, commercially available computing elements. Also included in the paper is a scaled analog circuit for simulating velocities and displacements for the four-bar linkage, along with records of these parameters from the author’s simulation.
Synthesis of Plane Linkages With Use of the Displacement Matrix
Authors: Suh C. H. , Radcliffe C. W.
Published: December 2011

A generalized matrix for the description of rigid body displacement in two dimensions is developed. This displacement matrix is applied to the synthesis of plane linkages used for rigid body guidance, path generation, and function generation.
Higher-Order Plane Motion Theories in Kinematic Synthesis
Authors: Sandor G. N. , Freudenstein F.
Published: December 2011

Algebraic multiple-position theories in kinematic synthesis are classified in a manner which also suggests various extensions of classical circular theory. In the case of infinitesimally separated positions, parabolic, elliptic, hyperbolic, and general conic-section theories are developed. The results, which are generally applicable, are illustrated with reference to the synthesis of cycloidal motions involving higher-order path generation.
Analysis of Residual, Thermal, and Loading Stresses in a B33 Wheel and Their Relationship to Fatigue Damage
Authors: Bruner J. P. , Benjamin G. N. , Bench D. M.
Published: December 2011

The current General Electric computer study sponsored by The American Iron and Steel Institute, discussed at the ASME Railroad Division 1965 Winter Meeting, has the objective of determining the most favorable geometric configuration to minimize service stresses. This present investigation involves the corollary problem of service loading conditions that produce the highest stresses and the possibility of fatigue damage. Static loading, rim heating, residual stress measurements, and fatigue tests were made in the laboratory on representative B33 wheels. A series of simulated loading conditions was studied and the resulting stresses combined by simple superposition principles. The resultant stress patterns were compared with fatigue test results using the modified Goodman relationship. In this way the service loading conditions that produce fatigue damage may be predicted.
Dynamic Coupling Effects in Rotary Face Seal Separation Phenomena
Authors: Hart F. D. , Zorowski C. F.
Published: December 2011

Dynamic separation phenomena in spring-supported rotary face seals are studied, employing a mathematical model which simulates the dynamic response characteristics of the system. Parameters considered in the model include support resilience, amplitude of shaft pulsation and mating ring wobble, initial preset, operating frequency, and contact surface friction. Inclusion of contact friction necessitates consideration of dynamic coupling in the equations governing the motion of the seal carrier. Combinations of operating conditions and system variables which produce incipient mechanical separation are predicted by examining the behavior of the contact force distribution between the seal and mating ring. Equations and graphs are presented which specify the theoretical preset required to maintain continuous contact as a function of the system parameters considered in the analysis.
Computer Application to the Visioplasticity Method
Authors: Shabaik A. , Kobayashi S.
Published: December 2011

Procedures for using a computer for the complete solution to plane strain as well as axisymmetric deformation problems have been developed. The velocity, strain rate, total effective strain, and stress distributions were obtained for two commercially pure lead specimens extruded in a forward extrusion process using white lead in oil as a lubricant. The axisymmetric extrusion was carried out at a speed of 1/8 ipm through a conical die having a 45 deg half-cone angle with a 2:1 extrusion ratio, and the plane-strain extrusion through a tapered die having a 45 deg half-taper angle with a 1.66:1 extrusion ratio.
Thermal Aspects of the Abrasive Cutoff Operation. Part 1—Theoretical Analysis
Authors: Eshghy S.
Published: December 2011

The heat transfer aspects of abrasive cutoff operation are investigated analytically. The analytical results lead to integral expressions for a dimensionless temperature of cutting interface as a function of dimensionless time and two dimensionless parameters. A rather simple expression is given which approximates the integral equations in a wide range of parameters. These results are dependent upon an important cutting parameter, namely, the “energy per unit volume” or the work necessary for removing a unit volume of chips. It is concluded that, if energy per unit volume decreases with downfeed faster than the latter to about −0.3 power, there exists a critical downfeed at which the temperatures will be maximum. For slower rates of decrease, lower temperatures are obtained at lower downfeeds. The partition functions for energy per unit volume, thermal penetration of the wheel, and experimental temperature measurements will be given in subsequent papers.
Inflation of a Plane Circular Membrane
Authors: Foster H. O.
Published: December 2011

An analytical solution has been found for the inflation of rubber-like membranes when the deformations are assumed to be large. Radial stretching of the membrane before inflation is incorporated into the problem. Experimental data for “Dental Dam” rubber show excellent agreement with the theory over the range of validity of the neo-Hookean strain energy function employed in the analyses.
Propagation of Longitudinal Waves in Circular Cylindrically Orthotropic Bars
Authors: Nowinski J. L.
Published: December 2011

Recent years have seen a revival of interest in the propagation of waves in anisotropic materials such as crystals, earth crust, reinforced plastics, and others. This paper investigates a rigorous theory of propagation of small disturbances in infinite cylindrically orthotropic bars of circular cross section. The field equations represent two coupled second-order differential equations for the radial and longitudinal displacements and involve seven elastic constants. They are solved by means of the Frobenius method using developments in power series in the radial coordinate, and assuming sinusoidal variation in the longitudinal coordinate and time. The boundary conditions of vanishing tractions on the curved surfaces of the bar supply two equations, whose nontrivial solution leads to the frequency equation. The first and the second-order approximations to the wave frequency are found which, for transverse isotropic and isotropic case, reduce to the classical results of Chree and Chree-Pochhammer. A simple formula for long waves is suggested.
Critical Pressure of Conical Acrylic Windows Under Short-Term Hydrostatic Loading
Authors: Stachiw J. D.
Published: December 2011

An experimental study has been conducted to determine the critical pressure of conical acrylic windows under short-term hydrostatic loading. Conical windows with 30, 60, 90, 120, and 150 deg included angle, and thickness-to-diameter ratios in the 0.125 to 1.0 range have been tested to destruction. Both their critical pressures and displacements through the mounting have been recorded and plotted for ready reference of designers.
Fracture of Abrasive Grain in Grinding
Authors: Eiss N. S.
Published: December 2011

The fracture strength of single grits of alumina abrasive grain, as observed while cutting mild steel, was measured as a function of the grain depth of cut, the tangential force during cutting, and the number of cuts made before fracture. A one-component force dynamometer with a natural frequency in excess of 20,000 cps was used to measure the variation in tangential force during a single cutting event which was typically 100 to 200 μsec in duration. Data are presented showing the distribution of tangential force as a function of depth of cut and the cumulative distributions of fracture stress and the number of cuts to failure. It is concluded that the failure mechanism during the first few cuts is different from the mechanisms which cause long-term failure. The definition of failure of grain over a long period must include progressive fracture and wear.
Metal Cutting as a Property Test
Authors: Lira F. , Thomsen E. G.
Published: December 2011

It is suggested that a metal-cutting test can be utilized as a high-strain-rate property test at strains larger than those normally achievable in conventional tests. The strain and strain-rate analysis is performed on the chip root of a composite specimen whose interface records the necessary information in terms of deformed grid lines which become streamlines. In the stress analysis, it is necessary to assume that the shear stress calculated from transducer forces is constant throughout a thin shear zone observed at the higher cutting speeds. The results can be converted into effective-stress and effective-strain data and should permit the establishment of stress, strain rate, strain, and temperature relationships for materials at the larger strains and at the higher strain rates.
Economics of the Abrasive Cutoff Operation
Authors: Farmer D. A. , Shaw M. C.
Published: December 2011

A minimum rate of wear exists at a particular downfeed rate in the abrasive cutoff operation. When the feed rate is lower than this value, wear is excessive due to high temperatures in the outer portions of the wheel. On the other hand, when the feed rate is higher than the minimum wear rate value, wear is also excessive due to insufficient space between active grains to accommodate the chips. In practice, a feed rate somewhat higher than the mininum wear rate value should be chosen since this will correspond to minimum cost per cut. Methods of arriving at the cost optimum downfeed rate for the abrasive cutoff operation are presented, including special charts for use in the workshop.
A New Approach to Determination of the Shear-Plane Angle in Machining
Authors: Rowe G. W. , Spick P. T.
Published: December 2011

A reevaluation of the minimum-energy type of solution for shear-plane angle has been made, without reference to a coefficient of friction. It is proposed that the shear plane will be oriented at an angle such that the total work done in plastic shearing of the metal, on the shear plane and at the rake face, has an extremum value. A full solution for nonhardening material is obtained, and this is extended to provide a qualitative explanation of chip thickening and the formation of a built-up edge with strain-hardening material and high rake-face stress. The importance of the length of contact on the rake face is emphasized.
Strain-Hardening and Strain-Rate Effects in Plastic Flow Through Conical Converging Dies
Authors: Avitzur B.
Published: December 2011

An upper-bound solution for energy expended to cause the flow of strain-hardening material through conical converging dies is presented. A linear strain-hardening coefficient is considered. The solution is adapted for determination of the required drawing force in wire drawing and the required ram force for extrusion. A simplified equation is then recommended, utilizing an expression for the average effective strain. The accuracy of the simplified equation was checked and found to agree within 1–2 percent with the upper-bound solution for all practical values of reduction, cone angle, and strain-hardening coefficients.
Rapid Filling of a Cylinder With a Compressible Fluid
Authors: Schmidlin A. E.
Published: December 2011

A study was made of the temperatures in a cylindrical receiver resulting from rapid filling with a compressible fluid. The classical bottle-filling case was compared with the filling of a slender cylinder. The results indicate that the isentropic temperature rise was never realized even in cylinders filled in 1/40 sec. The temperature field was studied using a linear partial differential equation in transformed coordinates developed by H. Pfriem. The case of a pressure transient linear in time was solved. Simple methods are presented for transforming the results back to physical or real variables.
Mass-Spring-Damper Response to Repetitive Impact
Authors: Park W. H.
Published: December 2011

The object of this research is the study of the response of a simple mass-spring-damper system to repetitive impact. The following analytical and experimental methods were employed: (a) Solution of the equations of motion by analytical and computational methods; (b) use of an experimental model to quantitatively establish the correspondence between the mathematical model and the real system; and (c) development of useful engineering data, charts, and curves from the analytical and experimental phases.
Statistical Energy Analysis of Vibrating Systems
Authors: Ungar Eric E.
Published: December 2011

The “statistical energy analysis” approach provides a relatively simple means for understanding and estimating the significant properties of multimodal random vibrations of complex systems, since this approach permits one to treat complex vibration problems in terms of much simpler energy balances. This paper delineates the concepts and relations which form the basis for the statistical energy approach, indicates its range of validity, and illustrates some of its applications.
Use of Mass as a Perturbation Parameter in Vibrations
Authors: Chicurel R. , Counts J.
Published: December 2011

Linear vibration problems involving harmonic excitation of discrete and continuous systems are solved by using the classical perturbation technique. The perturbation parameter is proportional to a mass and the square of the excitation frequency. The power series solution for the displacement of some point in the system is converted to the quotient of two polynomials by the use of continued fractions. The eigenvalues (natural frequencies) of the problem are calculated by finding the roots of the denominator polynomial. The situation wherein a quantity which cannot vanish at any frequency can be found is treated as a special case.
Torsional Instability of Fully Stalled Airfoil (or Supercavitating Hydrofoil)
Authors: Natesh M. S.
Published: December 2011

A theoretical study is carried out to determine the conditions under which steady-state pitching oscillations of an airfoil in one degree of freedom are possible in two-dimensional subsonic incompressible stalled flow using Parkin’s [1] coefficients. The results show that such oscillations can occur if the axis of rotation is located at a point that is approximately rearward of airfoil midchord but not too far rearward of the airfoil trailing edge. The practical significance of these results with respect to flutter is briefly examined. Torsional flutter [2] in the case of potential flow can occur only at very low reduced frequencies and under special circumstances, namely, when the rotation point is ahead of quarter chord, K′ > 550 and k < 0.0435. The significant difference between classical and stall flutter (torsional) is that the real part of the pitching moment coefficient [2] is negative in the former case and is positive in the latter case in the region of instability. Therefore, stall flutter can occur at very low values of K′, unlike classical flutter where K′ has to be greater than 550. The ratio of torsional natural frequency to flutter frequency is greater than 1 in the case of stall flutter, whereas in classical flutter the ratio is less than 1 because of the sign of the real part of the moment coefficient. A single-degree-of-freedom torsional flutter equation was derived, and by equating the real and the imaginary parts of the equation, relationships between the various flutter parameters were obtained. Stability boundaries were obtained for the structural damping coefficient gα = 0, 0.001, 0.005, 0.01, 0.02, 0.04, and 0.1 for various values of K′, namely, 5, 20, 40, 60, 80, 100, and 1000. The above values practically cover all airplane wings and compressor blades. The significant results are tabulated and some of the important parameters are plotted in the attached figures. By utilizing these figures, a typical airfoil in question could be checked, whether it is flutter-free or not, and if it is in flutter, all the flutter parameters could be determined. The analysis was conducted using Parkin’s coefficients [1], which require that the airfoil be completely stalled during the cycle.
Instability of Oil Bearings Due to High Oil Viscosity
Authors: Chen Y. N.
Published: December 2011

On a large turboblower running in oil bearings, it was found that the rotor became seriously unstable when the bearing oil temperature was low. It will be shown that this unstable vibration is due to the high bearing number effected by the high oil viscosity and its beating character is caused by the unequal elasticity of the bearing pedestals.