bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Design Variation on Service Stresses in Railroad Wheels
Authors: Bruner J. P. , Jones R. D. , Levy Samuel , Wandrisco J. M.
Published: December 2011

The satisfactory performance of a railroad wheel depends on its ability to withstand not only the repeated stresses imposed on it by normal loads and braking conditions, but also the occasional high stresses that develop under abnormal operating conditions. The continuing trend of present railroad operating practices toward higher wheel loads and speeds has created the need for better design criteria to insure that wheel configurations are the best attainable. Under sponsorship of the American Iron and Steel Institute, the General Electric Company developed computer programs to simulate service braking and loading conditions. These were reported at the 1965 ASME Winter Annual Meeting. Now the programs have been applied to different wheel designs and the braking and loading stresses computed. The results indicate that cyclic stresses of significant magnitude may occur under different operating conditions, so fatigue concepts are important in wheel design considerations. There was no one optimum wheel design for all possible service conditions, although several configurations showed promise. A method was proposed for optimizing design for specific service conditions to safeguard against fatigue damage. To fully utilize this technique for design optimization, accurate data relating to service conditions are needed.
Railroad Axle Design Factors
Authors: Byrne R.
Published: December 2011

Railroad axle designs have been developed from an application of theoretical principles of Reuleaux combined with extensive laboratory fatigue studies supplemented to some extent by road service tests. The designer is presented with data on the effects of the complex forces acting on axles operating in railroad service. Criteria for wheel seat and axle body stresses established from fatigue tests and modified by practical considerations are discussed. The paper gives elaborate reference material for use by future investigators of axle properties and designs.
Effects of Dynamic Chip-Breaking Upon Surface Microgeometry and Free Chip Dimension
Authors: Ostwald P. F. , Shamblin J. E.
Published: December 2011

A process called dynamic chip-breaking introduces a controlled low frequency vibration in the direction of the feed travel of a lathe tool. This superimposed vibration is given an amplitude such that continuous ductile chips are broken prematurely by the action of the tool. The dynamic chip-breaking process can be adjusted to give optimum values for the quality of the surface topography and free chip length. This exploratory study investigates the prospects of breaking chips from ductile materials by methods other than the conventional chip-curling type of breaker. Rational and empirical results are given which provide encouragement for additional development.
An Electron Diffraction Study of the Oxide Formed on Cemented Tungsten Carbide—Titanium Carbide Cutting Tools
Authors: Stanislao J. , Richman M. H. , James C. F.
Published: December 2011

The oxide protecting the surface of cemented carbide cutting tools containing both tungsten and titanium carbides is identified by electron diffraction as Ti2O3, which is formed during the cutting operations. This is a protective and adherent oxide which is formed as an intermediate layer between the TiC-TiO solid solution (the titanium carbide particle) and an outer layer of TiO2. The outer layer of TiO2 is spolled off by the abrasive action of the chip and only the Ti2O3 layer protects against welding of the chip fragments to the tool; and the protective layer retards tool wear.
Determining the Normal Stiffness of Joint Faces
Authors: Connolly R. , Thornley R. H.
Published: December 2011

The effect of load and types of finish on the stiffness of joints between machine surfaces has been investigated. An expression has been established between the normal load and the elastic stiffness of the joint. This expression has been verified experimentally. The relationship enables figures of merit (m) to be obtained for different surface conditions, different methods of machining, and different sizes of joints. A survey of industrial practice in the machining of joint surfaces has also been undertaken. This has provided a representative selection of machine finishes and enables quantitative figures to be quoted for typical joints.
Temperature Distributions in Drilling
Authors: DeVries M. F. , Saxena U. K. , Wu S. M.
Published: December 2011

An analytical temperature distribution along the cutting edge and on the flank face of a drill is obtained using Tsueda’s and Loewen and Shaw’s equations after modifications. Experimental temperature distributions are also investigated and the effects of a pilot hole and the heat sink are evaluated. Agreement between the analytical and experimental results is fairly close except near the chisel edge and near the drill periphery. The use of workpieces containing a pilot hole provides a method to account for the discrepancy between the analytical solution and the experimental results near the chisel edge while some explanation is offered to describe the discrepancy near the drill periphery.
Bending of Circular Plates Under a Uniform Load on a Concentric Circle—Part II
Authors: Heap J. C.
Published: December 2011

The basic equations of deflection, slope, and moments for a thin, flat, circular plate subjected to a uniform load on a concentric circle were derived for four generalized cases. From these generalized cases, six simplified cases were deduced. The four generalized cases have the uniform load acting on a concentric circle of the plate between the inner and outer edges, with the following boundary conditions: (a) Outer edge supported and fixed, inner edge fixed; (b) outer edge simply supported, inner edge free; (c) outer edge simply supported, inner edge fixed; and (d) outer edge supported and fixed, inner edge free.
A Stability Algorithm for a Special Case of the Milling Process: Contribution to Machine Tool Chatter Research—6
Authors: Hohn R. E. , Sridhar R. , Long G. W.
Published: December 2011

In an effort to determine the stability of the milling process, and due to the complexity of its describing equation, a special case of this equation is considered. In this way, it is possible to isolate and study its salient characteristics. Moreover, the simplified equation is representative of a machining operation on which experimental data can be obtained. This special case is described by a linear differential equation with periodic coefficients. A computer algorithm is developed for determining the stability of this equation. To demonstrate the use of the algorithm on an example whose solution is known, the classical Mathieu equation is studied. Also, experimental results on an actual machining operation described by this type of equation are compared to the results found using the stability algorithm. As a result of this work, some knowledge about the stability solution of the general milling process is obtained.
Basic Investigation of Built-Up-Edge
Authors: Takeyama H. , Ono T.
Published: December 2011

The formation of a built-up-edge has been differentiated into two mechanisms, that is, adhesion or nucleation of built-up-edge and growth of adhered metal. As to adhesion, the affinity between tool and work material has been investigated experimentally. The findings are that the position of a metal in the periodic table and the solubilities of the mating metals are substantially associated with the strength of adhesion. Although the temperature at the interface is primarily significant to accelerate the adhesion, the effect of relative velocity has been revealed to be negligible. Theoretical analogy and experimental analysis have led to a conclusion that work-hardenability is a requisite condition for the existence and growth of built-up-edge.
An Investigation of Analog Materials for the Study of Deformations in Metal Processing Simulations
Authors: Chang K. T. , Brittain T. M.
Published: December 2011

Many materials were surveyed with the hope of finding a material which could be used in room temperature simulations of forming processes on hot steel—particularly the process of the rotary piercing of tubes. By comparing the results of simulations on a model mill with the results of an actual production process, it was found that a composition of 81.0 percent (by weight) Plasticine clay, 16.2 percent kaolin, and 2.8 percent paraffin proved to be an excellent, if not optimum, analog material when used at 55 deg F. As a result of strength data collected in this investigation it is expected that this composition-temperature combination might also be used for the simulation of the plastic deformation of steel at room temperature.
Plastic Instability in Simple Stretching of Sheet Metals
Authors: Negroni F. , Kobayashi S. , Thomsen E. G.
Published: December 2011

The plastic instability was examined for stretching a plane flat sheet by in-plane tensile principal stresses. Limiting equilibrium or development of nonuniform strains defines the onset of plastic instability. Under dead loading the Swift theory gives the conditions for limiting equilibrium, while it results in the condition for the failure of uniqueness for given strain paths. When the initial nonuniformity of the properties and dimensions in the sheet is considered, the Dorn maximum load criterion is applicable for the condition of plastic instability. The optimum paths along which the maximum strains can be achieved before instability takes place were obtained and the limiting maximum strains was calculated along these paths for the Dorn criterion and for the Swift theory.
A New Method of Testing the Surface Finish of a Metal
Authors: Panda B. C.
Published: December 2011

A sensitive method of testing the surface finish of a metal has been suggested based on the principle of field emission. The quasi-classical calculation of the field-emission current from a plane metal surface shows that the calculated current is always less than the experimental current. The discrepancy between these theoretical and experimental currents has been shown to be a measure of the nonplanarity of the metal surface from which one can get information about how much finish a particular metal surface can take.
Analysis of a High-Speed Solenoid-Actuated Mechanism
Authors: Wirth R. L.
Published: December 2011

The mechanism which is considered in this paper is a high-speed, solenoid-driven, impact printing mechanism. The purpose of the analysis is to construct a mathematical model of the mechanism from which the dynamics of the mechanism can be studied during a complete printing cycle. The basic approach taken is to construct a lumped parameter model of the mechanical system. Motion equations are written which are solved simultaneously with equations governing the electromagnetic system. Elements of the mechanical system which are described include viscoelastic buffers between impacting parts. Dead space or intermittent contact between parts is another aspect of the problem which is defined. The relationship between core flux and impressed current is established through an experimentally measured magnetization curve. Equations governing both the rise and fall of the magnetic flux are developed since a complete cycle of operation is under study. The resulting set of equations is nonlinear in nature and impractical to solve by hand. However, a systematic solution to the equations is readily obtained by numerical integration on a digital computer.
Three-Dimensional Kinematic Synthesis
Authors: Tull H. G. , Lewis D. W.
Published: December 2011

A synthesis technique applicable to the three-dimensional mechanisms of the RRGG type to generate specified arbitrary space curves is presented. Specified points which define the curve are to be “occupied” at specific crank rotation with respect to an arbitrary reference angle. Synthesis is by use of new steepest descent method converging from any starting approximation (even very poor ones) to a local minimum of the sum of the squares of the errors.
Motion of an Elastic Rod With External Coulomb Friction
Authors: Wilms E. V. , Wempner G. A.
Published: December 2011

The effect of external friction on an elastic rod is considered for the case of a sudden application of force to one end. The interesting result obtained is that the maximum distance which the wave propagates down the rod is independent of the material properties land depends only on the applied force at the end and on the friction force.
An Integral Analysis of Turbulent Reattachment Applied to Plane Supersonic Base Flows
Authors: Lamb J. P. , Hood C. G.
Published: December 2011

A conceptually simple control volume analysis of plane turbulent reattachment in isoenergetic base/wake regions with no mass bleed, has been demonstrated to yield wall static pressure distributions which are in reasonable agreement with available measurements for approach Mach numbers up to 4.5. The analysis, which assumes free interaction in the reattachment region, utilizes a numerical search technique to determine conditions which satisfy the necessary integral conservation equations and geometric conditions. The successful prediction of pressure distributions by this theory tends to confirm (i) the validity of the Chapman-Korst isentropic escape criterion as a satisfactory technique for identification of the dividing streamline rather than as a thermodynamic specification of the dividing streamline stagnation process, (ii) the feasibility of ignoring both upstream boundary layer and corner flow influences in the determination of conditions in the lower portion of the free shear layer, and (iii) the suitability of utilizing a first-order free interaction analysis for obtaining indicative results for the redeveloping wall layer downstream of reattachment.
Advanced Developments in Hard Space Suit Technology
Authors: Vykukal H. C.
Published: December 2011

A hard space suit suitable for use on planetary surfaces and for other extravehicular activities has been designed and fabricated at the Ames Research Center. Except for the use of soft gloves, the suit is constructed completely of hard materials and allows for exceptional mobility with low torques and leakage. There are no restoring torques in the constant volume joints; that is, the joints are neutrally stable in any position in which they are placed.
A Method of Estimating the Optimum Mean Life of Plant Groups
Authors: Brennan J. F.
Published: December 2011

This paper describes a method of optimizing average service life of plant groups. The method is stochastic or statistical rather than deterministic, in the sense that a time-frequency distribution of failures is employed. Simplified methods are introduced for determining current average life and for correlating maintenance expense with age of plant. The effects of replacement and of inflation are considered. An example of a computer solution is given.
Assessment of the Plastic Strength of Pressure Vessel Nozzles
Authors: Rodabaugh E. C. , Cloud R. L.
Published: December 2011

Theoretical developments on limit pressures of shells are cited and briefly discussed. Calculated limit pressure from several of the theoretical analyses are compared with numerous tests on radial nozzles in both spherical and cylindrical vessels. Test data on burst pressures of nozzles in cylindrical vessels are presented and compared with limit pressures.
Digital Computer Simulation of Railroad Freight Car Rocking
Authors: Liepins A. A.
Published: December 2011

A mathematical model for the simulation of railroad freight car rocking is presented. The equations of the model are developed into a digital computer program. The model response is validated by two series of test results, and the model is considered reliable for engineering predictions.
Suspension Dynamics by Computer Simulation
Authors: Diboll W. B. , Bieniecki H. S.
Published: December 2011

An analytical study of the effect of changing the design parameters of a two mass, six-degree-of-freedom suspension system was made. Rail cars with coil and air springs were analyzed by analog and digital computer. Spring stiffness, spring spacing, damping rates, height of center of gravity, and total mass were varied. The effect on frequency and response were determined.
The Effects of the Lateral Instability of High Center of Gravity Freight Cars
Authors: Wiebe D.
Published: December 2011

High center of gravity freight cars experience extreme weight shift from side to side as a result of lateral resonance on track with cross-level differences from alternately staggered joints, as well as soft or other local variations in either rail. Dynamic measurements from tests made on test track with controlled 3/4-in. cross-level difference changes illustrate the force and motion magnitudes resulting from resonant and near resonant operating speeds; side bearing loads of 138,000 lb and spring group loads of 100,000 lb, accompanied by center plates separating and wheels lifting. The rotational energy input to the car body can be approximated for a given motion cycle and is proportional to the product of the amplitudes of the track profile and the car body motion. The high lateral (horizontal) forces on the truck at the side bearing and center plate make the truck unstable and cause wheels to lift off the rail on one side. This lateral force at a given end of the car is proportional to the corresponding vertical side bearing load. Freight cars traveling at resonant speed are especially prone to derail on curved track under high wheel-rail friction conditions. Forces and motion generated between the car body, truck, and the track, cause high cyclical stresses and severe wear between components that can shorten equipment life and cause severe track maintenance problems.
Analysis of the Time-Dependence of Multi-Freedom Mechanical Systems in Relative Coordinates
Authors: Chace M. A.
Published: December 2011

A theoretical model and a computational procedure are proposed for the analysis of the time-dependence of highly constrained, multi-degree-of-freedom mechanical systems. Problems are formulated as a simultaneous set of Lagrange differential equations in the system relative coordinates, accompanied by second-order constraints. The equations are linear in the second-order terms and are solved by a numerical integration procedure.
Some Applications of Graph Theory to the Structural Analysis of Mechanisms
Authors: Dobrjanskyj L. , Freudenstein F.
Published: December 2011

Concepts in graph theory, which have been described elsewhere [2, 4, 6] have been applied to the development of (a) a computerized method for determining structural identity (isomorphism) between kinematic chains, (b) a method for the automatic sketching of the graph of a mechanism defined by its incidence matrix, and (c) the systematic enumeration of general, single-loop constrained spatial mechanisms. These developments, it is believed, demonstrate the feasibility of computer-aided techniques in the initial stages of the design of mechanical systems.
The Design of the Spherical Drag-Link Mechanism
Authors: Soni A. H. , Harrisberger L.
Published: December 2011

The spherical drag-link mechanism has been designed using an approach based on minimum transmission angle. Explicit relationships have been derived for the required dimensions which satisfy the criteria of minimum transmission angle, and a design chart for the solution of spherical drag-link mechanisms (similar to that of Hain) is presented. Also, the seven cognates of the spherical drag-link mechanisms are identified and discussed.
Low-Cycle Fatigue of Large-Diameter Bolts
Authors: Snow A. L. , Langer B. F.
Published: December 2011

New constant-deflection amplitude fatigue data on bolting materials are presented. The relationship of cyclic yield strength to static yield strength is examined. Several series of full-size stud fatigue tests are analyzed and compared to the basic failure curve to obtain experimental fatigue strength reduction factors for bolts and studs. The variation of fatigue strength reduction factors with thread root radius, stud size, thread taper, and other variables is noted. A new design fatigue curve for bolts is proposed which reflects the additional information available at the present time.
Report of Committee RR-6 Survey: Progress in Railway Mechanical Engineering, 1965–1966
Authors: Bateson N. E. , Lich R. L. , Baker P. H.
Published: December 2011

This paper contains the annual report of the ASME Survey Committee RR-6. Developments in Railway Mechanical Engineering from September 1, 1965, to September 1, 1966, which pertain to railcars and locomotives are discussed. A review of technical achievements incorporated in locomotives, rapid transit, and freight cars introduced in North America, Europe, and Asia is described and pictured.
Transient Thermal Stress and Associated Natural Frequency Variations in Circular Disk Elements
Authors: Mote C. D.
Published: December 2011

Most available thermal stress and associated natural frequency analyses of circular disk elements incorporate only the steady-state temperature distribution and intuitively assume that the transient is not significant. An analytical rule-of-thumb involving the calculation and test of a nondimensional number h1 is proposed for predicting conditions when the transient regime may be significantly more severe than the steady state. The number h1 = hb2/ksa, a modified Biot number, involves disk surface heat transfer, disk conductivity, and geometry.
In-Plane Bending of a Short-Radius Curved Pipe Bend
Authors: Jones N.
Published: December 2011

The analysis developed in this article is a logical extension, or generalization, of Von Karman’s original theory [1] on curved pipe bends. It can be shown, for long-radius pipe bends which have a negligible shift of the neutral axis, that the solution presented here reduces to that of Von Karman. It is evident from the results of this analysis that the stresses in and flexibility of curved pipe bends are virtually independent of γ(a/ρ) (even for γ approaching unity) and depend almost entirely on the simple Von Karman pipe factor λ(tρ/a2). Errors arising from premature truncation of the selected power series for the radial displacement are discussed, and a guide given to the number of terms necessary for a particular problem.
Beating in Three-Mass Systems Under Step Velocity Input. Part 1—Analytical
Authors: Stokey W. F. , Wunder R. A.
Published: December 2011

The response of three-mass systems to step changes of the base velocity is discussed. It is shown that beating, which may occur between the vibrations in two normal modes, can result in a large increase in the maximum acceleration, or effective static force, undergone by one of the masses. Included are curves which show the maximum effective static forces on the system masses, and the beat frequency, for a wide range of system parameters.
A Remote Sensor Method for Determining Average Tool-Chip Interface Temperatures in Metal Cutting
Authors: Lipman M. P. , Nevis B. E. , Kane G. E.
Published: December 2011

This paper shows the development of a mathematical model for determining the average interface temperatures when using a remote sensor. The accuracy of the remote sensor technique was greatly improved by introducing an insulator between the tool and tool-holder. The presence of the insulator provided boundary conditions which enabled a numerical solution to the set of equations representing heat flow and temperature distribution. The model was compared experimentally with a tool-chip thermocouple, and agreement of the order of ± 6 percent was observed. The model can be used not only to determine the average tool-chip interface temperature, but the temperature distribution of the overall tool. The developed model proved to be somewhat insensitive to physical constants and the surrounding environment. Its use as a practical, accurate method for determining cutting temperatures is possible without the need for calibrating tool-chip thermocouples, complicated experimental setups, tedious iterative calculations, over-generalized assumptions, and unavailable physical constants for tools and work materials.
A New Explanation of the Phenomenon of Chip Curling During Machining
Authors: Ponkshe G. R.
Published: December 2011

None of the existing explanations suggested by various research workers satisfactorily explains the various degrees of chip curl observed under different cutting conditions. A new explanation of the same, based on the shear strain theory and derived from the slip line field, has been presented in this paper and its validity has been discussed under various conditions of cutting.
Three-Dimensional Variation Diagrams for Control of Calculations in Optimum Design
Authors: Johnson R. C.
Published: December 2011

This paper presents and illustrates a graphical technique for the control of calculations in the procedure of optimum mechanical design. This three-dimensional variation diagram technique minimizes the number of calculations required for the determination of the optimum design, and the general technique is applicable to many problems. Specific practical examples are given for the optimum design of a torsion bar and for the optimum design of a gearset.
Optimization of Orthotropic Laminates
Authors: Fischer L.
Published: December 2011

Stress-strain relationships for a single layer are used to obtain the stress distribution in a laminate composed of any number of orthotropic layers subjected to axial and shear stresses. The mathematical procedure is simplified for an isotropic laminate. An interaction equation is presented to predict failure of a laminate. Optimum structural design criteria are obtained by considering different combinations of layer orientations.
Comments on Long Trains
Authors: McDowell E. L.
Published: December 2011

In this paper, equations of motion appropriate to long trains are derived which include the effects of undulating terrain. The formulation of a nonlinear dynamic programming problem to be applied to “programmed braking” is presented and the class of problems within the capability of available computing equipment is discussed. An analysis of the effect of undulating terrain on the operational response of long traveling at constant speed is presented in detail and numerical results for particular train configurations are given. In particular, the critical velocity for longitudinal resonance as a function of train length and terrain characteristic is given, and from the specialized results for the uniform train it is possible to discern the influence of changes in car mass, coupling stiffness, and so on.
Low-Cycle Fatigue Behavior of Internally Pressurized Boxes
Authors: Gross M. R. , Heise R. E.
Published: December 2011

One phase of a continuing study of the low-cycle fatigue behavior of metals for deep submergence structural applications involves the validity of simple specimen results when applied to complex structures. As a part of this study, the low-cycle fatigue performance of twelve internally pressurized boxes was investigated. The boxes were constructed from 1-in-thick plate of six materials consisting of three steels, one aluminum alloy, and two titanium alloys. The boxes were cyclically pressurized at peak nominal stresses up to about 80 percent of the yield strength of the base metal. The results are compared with data previously obtained for simple laboratory specimens. The results of the box tests tend to confirm two general conclusions reached previously from simple specimen tests, that is: (1) Increases in low-cycle fatigue strength for a given life are not commensurate with increases in yield strength, and (2) low-cycle fatigue life is closely related to total strain range and appears to be independent of both structural metal and strength level in the life range of 1000 to 30,000 cycles.
An Analytical and Experimental Evaluation of the Damping Capacity of Sandwich Beams With Viscoelastic Cores
Authors: Jones I. W. , Salerno V. L. , Savacchio A.
Published: December 2011

A study is made of the free vibrations of sandwich beams with viscoelastic cores. The study, which is a generalization of a previous investigation by the authors [1] includes the equations of motion and natural boundary conditions, derivation of expressions for the modal distribution of damping based upon “small damping” assumptions, numerical examples, and a supporting test program. The generally high values calculated for beams of various materials indicate that this type of construction is efficient for vibration damping applications. It was found, however, that the calculated and test values were not in accord. This lack of agreement signifies the necessity for greater refinement in both analytical methods and test procedures.
Radial Expansion of Hot-Machined Workpieces
Authors: Ichimiya R.
Published: December 2011

This paper presents the results of research on the influence of radial expansion on the final dimensions of the workpiece when machining it at elevated temperatures. Equations are developed for temperature distributions and radial expansions of the workpieces, including the effects of the cooling time in air. Three basic heating methods are studied: Through-heating, line heat source, and point heat source. In addition, numerical and experimental results of the through-heating method are presented. Also, theoretical analysis and experimental results are discussed in detail. The results show temperature distributions within and the variations of the workpiece diameter caused by temperature and cooling time.
Application of Potential Flow Theory to Plane-Strain Extrusion
Authors: Shabaik A. , Kobayashi S. , Thomsen E. G.
Published: December 2011

Theoretical and experimental flow fields of several extrusion ratios of lead in plane strain were compared. It was found that, for extrusion ratios where dead metal exists, the agreement between the potential and experimental flow nets was better for small reductions when a modified boundary approaching a flow line was used. It was also found that when the flow changed direction gradually, the potential flow net was in good agreement with the experimental one. The solution obtained is unique and complete.
Some Aspects of the Dynamic Similarity in Metal Cutting
Authors: Hsu Tao-Ching
Published: December 2011

A new approach to the mechanics of metal cutting is demonstrated by applying the principle of dynamic similarity to the plastic flow in the cutting process. In accordance with known effects of temperature and strain rate on the flow stress of materials, three dimensionless parameters are chosen by theoretical considerations, two for temperature distribution and one for strain rate effects. For convenience, a secondary set of dimensionless parameters is derived from the first. Nondimensional cutting force and non-dimensional stresses on the tool face are defined. Successful application of dimensional analysis to experimental results is presented.
Thermal Analysis of Metal Flow at the Chip-Tool Interface in Metal Cutting
Authors: Scrutton R. F.
Published: December 2011

The plastic flow of metal adjacent to the chip-tool interface is analyzed using a mechanical equation of state, which relates the variables stress, strain, strain rate, and temperature. Expressions are derived for the temperature at points within the thin plastic layer. The assumptions, which are similar to those used in the theory of viscous boundary layers, include the hypothesis that the shear stress is constant throughout the layer.
Metal Cutting Analysis: Introduction to a New Theoretical Approach
Authors: Vidal Jessen
Published: December 2011

In this work, the author develops a new approach to the theory of the cutting mechanism based on the comparative analysis of classical theories. He suggests the introduction of an empirical parameter E, related to the efficiency, which modifies the Lee-Shaffer solution; at E = 1, the theory reduces to the latter theory.
An Explanation of the Apparent Bridgman Effect in Merchant’s Orthogonal Cutting Results
Authors: Oxley P. L. B. , Welsh M. J. M.
Published: December 2011

In Merchant’s modified shear angle solution, it is assumed following Bridgman that the shear strength of the work material is a function of the hydrostatic stress. Although Merchant’s experimental results confirm the assumed relation, subsequent workers have failed to obtain such agreement. In this paper, it is shown that Merchant’s results can be explained independently of the Bridgman effect by considering the variable flow stress properties of the work material, which are strain-rate dependent.
The Influence of Pressure Cycling on Thermal Regenerators
Authors: Rea S. N. , Smith J. L.
Published: December 2011

A theoretical and experimental investigation examines the performance of thermal regenerators in which rapid flow cycling is accompanied by large pressure variations with time. This class of regenerators is characterized by two basic parameters: (a) the ratio of the convective heat transfer within the regenerator to the work of compression, and (b) the ratio of the rate of mass storage within the regenerator void volume to the through-flow. The definition of heat exchanger effectiveness is extended to include the effects of mass storage within the regenerator void volume. A method of predicting this effectiveness is presented.
Transition Mechanisms Attendant to Large Amplitude Parametric Vibrations of Rectangular Plates
Authors: Somerset J. H.
Published: December 2011

Experiments have been conducted to investigate the transition mechanisms attendant to the parametric vibrations of a simply supported rectangular plate subjected to a periodic load of the form P = P0 + P1 cos γt. It is found that the transition mechanisms, such as “jumps” within the zone and “dropout” from the zone, are influenced by the initial curvature of the plate and by interactions with the source of energy. Due to the possibility of transitions between the parametric oscillations and forced vibrations of the plate, “splitting” of the zone may occur. Preliminary experiments indicate that the transition mechanisms have a strong influence on the response of the plate to stochastic loading.
On the Critical Speeds of a Continuous Shaft-Disk System
Authors: Eshleman R. L. , Eubanks R. A.
Published: December 2011

The effect of gyroscopic moments on the critical speeds of a shaft-disk system mounted in short end bearings is investigated. Representation of the shaft as having continuously distributed mass and elasticity allows accurate determination of higher critical speeds. Frequency equations are obtained for the critical speeds associated with both backward and forward whirling modes. The first four critical speeds (backward and forward whirling modes) are given for a range of shaft and disk sizes and for various disk locations on the shaft. Experimental verification is given for the first and second critical speeds.
On Precession and Critical Speeds of Two-Bearing Machines With Overhung Weight
Authors: Huang T. C. , Huang Frank C. C.
Published: December 2011

A study has been made to analytically determine the angular precession and critical speeds of two-bearing machines with overhung weight. The gyroscopic moment (when rotating), rotatory inertia (when not rotating), and shear deformation (in each case) are considered. Rotor precession of all types and critical frequency of nonrotating shaft are analyzed and presented.
The Design and Evaluation of a Supercritical-Speed Helicopter Power-Transmission Shaft
Authors: Prause R. H. , Meacham H. C. , Voorhees J. E.
Published: December 2011

A series of research programs with small-diameter, supercritical-speed power-transmission shafting has led to the development of design techniques for the application of one or two viscous dampers to control shaft vibrations through as many as 20 critical speeds. These techniques have been used to design a large, 338.5-in-long helicopter rotor synchronizing shaft using aluminum tubing with an outside diameter of 4.50 in. and a wall thickness of 0.12 in. A single viscous damper located 30.0 in. from one end of the shaft has been used to successfully operate the shaft through its first five critical speeds. The design parameters and experimental results for this shaft are discussed, along with a description of the application of modal balancing at the third, fourth, and fifth critical speeds.
The Electrodynamic Vibration Absorber as a Passive or Active Device
Authors: Abu-Akeel A. K.
Published: December 2011

The theory of a new damper is derived and verified experimentally. The damper utilizes an electric armature elastically coupled to its field stator which is fixed to the vibrating system. The electric energy output is discharged through an electric network. The damper compares favorably to a dynamic absorber. When active feedback is utilized, much better efficiency can be obtained. Optimum tuning can be attained by relating the resonant frequency of the electric current to that of the main system. Damping is provided through the electric circuit and adjusted by varying either the resistance of the circuit or the magnetic field strength. Eliminating the spring coupling between the armature and the vibrating system results in a system similar to the Lanchester damper, with much higher efficiency. The absorber can be applied to torsional as well as unidirectional (lineal) vibrations at any practical frequency range. The experimental damper, with a mass ratio of 1/71, produced an optimum magnification factor of 10.5 comparable to a dynamic absorber at similar conditions. The theory of this passive damper is modified to account for feedback conditions. A signal proportional to the strain in the elastic support of the vibrating system is amplified and fed to the armature of the damper through the proper transfer network. Under sinusoidal force input, the experimental characteristics displayed a fairly flat response. With an armature mass of 1/340 of that of the vibrating system, a maximum magnification factor of only 4 was obtained experimentally. Both theoretical and experimental response plots are given and analyzed under different feedback conditions. The damper with feedback may be employed without external viscous damping and the frequency tuning can be achieved by the proper choice of the feedback network. Because of its construction as an electric machine, it is foreseen to be applicable in mechanical and control systems. The characteristics presented add in a detailed fashion to those reported in the literature for similar feedback applications.
Surface and Wake Flow Phenomena of the Vortex-Excited Oscillation of a Circular Cylinder
Authors: Ferguson N. , Parkinson G. V.
Published: December 2011

Using an original design of acoustic-level pressure transducer, measurements were made of fluctuating pressures on the surface and in the wake of a circular cylinder at rest and in vortex-excited oscillation at subcritical Reynolds numbers. Frequency, amplitude, and phase, where relevant, of the cylinder oscillation were also measured, and some effects of cylinder oscillation on the organized wake geometry were observed. The new results are compared with relevant existing information for the stationary cylinder, and with the few measurements previously available for the oscillating cylinder, and some analysis is made.
Design and Analysis of Welded Pressure-Vessel Skirt Supports
Authors: Weil N. A. , Murphy J. J.
Published: December 2011

Factors determining the performance of welded skirt supports for vertical process vessels are discussed. The importance of thermal effects is emphasized. A comprehensive analysis of local stresses with closed-form solutions is presented, permitting assessment of expected performance in service on a fatigue basis. The expected shape of skirt distortion is briefly mentioned. Suggestions and recommendations are made for design practice, control of thermal stresses, weld and fabrication detail for optimum practical quality, as dictated by service conditions. A numerical example is presented to illustrate the application of the analysis.
Tire Testing
Authors: Hannell John W.
Published: December 2011

The use of tire tests for fiber characterization in research programs aimed at the development of improved tire yarns is discussed. Examples are included to demonstrate some of the factors which influence tire impact, fatigue, and heat resistance. The test results can be generally related to specific tire cord properties, thus defining the areas in which research should be concentrated.
The Effect of Presetting Helical Compression Springs
Authors: Atterbury T. J. , Diboll W. B.
Published: December 2011

A procedure for predicting the increase in fatigue load carrying capacity due to presetting helical springs is developed, based on the actual stress-strain curve of a material. Reasonable correlation with experimental results is obtained. For the cyclic load conditions and the material chosen, an increase in load carrying capacity of 21 per cent was observed. It is expected that an increase of approximately 40 per cent could be realized with slight modification of fabrication techniques.
A Quantitative Investigation of the Factors Which Influence the Fatigue Life of a V-Belt
Authors: Marco S. M. , Starkey W. L. , Hornung K. G.
Published: December 2011

A new design method for V-belts has been developed. The new method involves a horsepower-life relationship which has been derived on the basis of the results of a vast experimental program of belt testing involving many hundreds of tests, together with an analysis of these data which introduces several new concepts of stress analysis for rubber-textile structures.
Edge Influence Coefficients for Toroidal Shells of Positive Gaussian Curvature
Authors: Galletly G. D.
Published: December 2011

Tables are given for the edge deformations of constant-thickness toroidal shells subject to uniform pressure and edge bending loads. Over one hundred different shell geometries were investigated and the results are presented in dimensionless form. Possession of these coefficients, which were obtained on a digital computer, means that a rapid and accurate formulation of the compatibility equations at toroidal shell junctions is now possible.
Edge Influence Coefficients for Toroidal Shells of Negative Gaussian Curvature
Authors: Galletly G. D.
Published: December 2011

Continuing the work presented in reference [1], the present paper gives additional tables for the edge deformations of constant-thickness toroidal shells subject to edge bending loads and uniform pressure. The two papers together thus cover a wide variety of toroidal shell geometries and enable a designer to calculate in a simple manner the edge moments and shears at toroidal shell junctions.
Shear-Zone Size, Compressive Stress, and Shear Strain in Metal-Cutting and Their Effects on Mean Shear-Flow Stress
Authors: Kececioglu Dimitri
Published: December 2011

A relationship for the calculation of the shear-zone size is given. The shear-zone size, when machining SAE 1015, 118-Bhn seamless steel tubing under a wide range of cutting conditions, is found to vary from 0.95 × 10−6 in.3 to 61.5 × 10−6 in.3 The mean shear-flow stress is found to increase significantly with a decrease in the shear-zone size and with an increase in the compressive stress in the shear zone. It is concluded that the only size effect in metal-cutting is the shear-zone size effect, and that no separate depth-of-cut size effect should be sought. An apparent decrease in the shear-flow stress with an increase in the true, mean shear strain in the shear zone is observed, and this behavior is explained.
Overstrain Tests on Thick-Walled Cylinders
Authors: Jorgensen S. M.
Published: December 2011

The experimental work described in the following covers pressure-expansion tests on thick-walled, closed-end cylinders of four different steels. The tests covered stress levels through the plastic and strain-hardening ranger to destruction, at pressures up to 100,000 psi. A theoretical method is given for computing expansion and bursting strength, based on both tension and torsion data. Finally, a simplified formula for ultimate pressures is described and checked against the experimental data.
The Strength of Thick Cylinders Subjected to Repeated Internal Pressure
Authors: Morrison J. L. M. , Crossland B. , Parry J. S. C.
Published: December 2011

In April, 1956, the authors presented to The Institution of Mechanical Engineers a paper entitled “Fatigue Under Triaxial Stress: Development of a Testing Machine and Preliminary Results,” and in September, 1956, a supplementary paper was presented to the International Conference on the “Fatigue of Metals.” These papers reported tests carried out on cylinders made from a 2 1/2 per cent Ni-Cr-Mo steel, which were subjected to (up to) ten million repetitions of internal oil pressure of (up to) 45,000 psi. Since the publication of these papers a considerable amount of testing has been carried out on cylinders made from a carbon steel, a 3 per cent chrome steel, an austenitic stainless steel, a light alloy, a nearly pure titanium, the Ni-Cr-Mo steel in a harder state, and both the Ni-Cr-Mo steel and the chrome steel in the nitrided condition. In addition, many tests of more academic significance have been carried out on the Ni-Cr-Mo steel in an attempt to achieve a better understanding of the extraordinary results which have been obtained. This paper is concerned mainly with the presentation of the results (supported, of course, by ancillary tests on each material), which are of importance in design. Points of academic interest are discussed only when they are relevant to the practical problem. In order to make the paper reasonably self-contained, a brief summary of the previous work is given, together with a short description of the machine which has been developed for this work.
Simplified Approach to Understanding the Suction Problems for Reciprocating Mud Pumps
Authors: Liljestrand Walter E.
Published: December 2011

There are no standards or generally approved formulas for designing or analyzing mud-pump suction systems such as already worked out for centrifugal pumps. This paper analyzes pump-suction and suction-piping characteristics showing responsibility areas of users and manufacturers. Empirical formulas and verifying test procedures are explained. This material should be used as a basis for preparation of standards on pump suction systems as used in the oil field. It will reduce pumping troubles and costs and permit increased pump output.
Helixform Bevel and Hypoid Gears
Authors: Spear G. M. , King C. B. , Baxter M. L.
Published: December 2011

The Helixform process is a recent development in the art of gear cutting. Gears made by this method are classified as nongenerated which means that the workpiece remains at rest while the teeth are being cut. Cutting the gear without generation is a process especially adapted to high production and accurate machining and is the method used to manufacture most automotive spiral bevel and hypoid gears. Pinions which match nongenerated gears are of course produced with generating motion, that is, the tools cutting the teeth of the pinion are mounted on a machine element which, while the teeth are being cut, turns in concord with the turning of the pinion on its axis.
An Analysis of Factors Used for Strength Rating Helical Gears
Authors: Wellauer E. J.
Published: December 2011

This paper discusses the factors used to rate the strength of helical-gear teeth by means of the fundamental tooth-strength formula developed by the American Gear Manufacturers Association’s Gear Rating Committee. The new approach combines different concepts of geometry factors, an improved evaluation of dynamic loads, rational allowable stresses, and risk or reliability considered as a statistical probability. In addition, the inclusion of the effect of operating error and load-distributing tooth flexibility provides the gear engineer with a more accurate means for helical-gear strength rating.