bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Analysis of Large Systems by Complex Mode Synthesis
Authors: Hasselman T. K. , Kaplan A.
Published: November 2010

The method of component mode synthesis, originally conceived for application to lightly damped structures, is extended to include linear, autonomous, holonomic dynamical systems in general. When written in terms of generalized coordinates, the equations of motion may have completely arbitrary constant coefficients. The work was initially developed for the analysis of high speed trains which exhibit discrete damping in their suspension systems, and nonsymmetry of the coefficient matrices due to wheel-rail interaction and the possibility of Coriolis coupling from spinning wheels and rotors. The object of component mode synthesis is to minimize the number of equations which must be solved for either stability analysis of dynamic response analysis of multi-component systems. Formulation of the equations in terms of the modal vectors associated with isolated subsystems is found to satisfy this objective. The modes are considered to be complex in general as opposed to the classical normal modes in structural dynamics which are always real. A method for computing the frequency response of a system to sinusoidal excitation is described. It is valid over a frequency range determined by the component modes included in the analysis. An example is discussed which illustrates the effectiveness of this approach in terms of reducing the computational effort required to obtain accurate modes for the complete system.
Recent Developments in Control Theory in Austria, Switzerland, and Western Germany
Authors: Pohl W. , Thoma M.
Published: November 2010

Contributions in the field of control theory by authors from Austria, Switzerland, and Western Germany from 1970 until the present are reviewed. Six topics are discussed: Stability, Distributed Parameter Systems, System Theory, Sampled-Data Systems, Identification, and Optimization. Each of these sections contains short comments on important papers in the corresponding fields which were extracted from commonly available literature. Seventy-two references are given, most of which are written in the English language. The majority of the papers are not pure mathematical problems, but applications of modern control theory.
Cellular Logical Networks
Authors: David R. , Richard J. P.
Published: November 2010

Two works are described in this paper. The first is concerned with a synthesis method of asynchronous sequential systems with Universal Cells CUSA. The second describes a combinational system synthesis by cellular arrays.
Response of Continuous Periodically Supported Guideway Beams to Traveling Vehicle Loads
Authors: Smith C. C. , Wormley D. N.
Published: November 2010

The response of continuous span periodically supported guideway beams to traveling vehicle loads is determined using Fourier transform techniques. Vehicle loads are assumed to travel at constant speed with constant magnitude and may be spacially concentrated or distributed to represent wheeled, air cushion, or magnetic suspension vehicles. Guideway dynamic amplification factors and deflection profiles are presented in detail for the single concentrated traveling load. Operating regions in which dynamic resonance conditions occur are identified, and the influence of span damping is evaluated. Guidelines for the formulation of finite span approximations to the infinite continuous span guideway are also developed.
Optimal Control of a Distributed Parameter, Time-Lagged River Aeration System
Authors: O¨zgo¨ren M. K. , Longman R. W. , Cooper C. A.
Published: November 2010

The control of artificial in-stream aeration of polluted rivers with multiple waste effluent sources is treated. The optimal feedback control law for this distributed parameter system is determined by solving the partial differential equations along characteristic lines. In this process the double integral cost functional of the distributed parameter system is reduced to a single integral cost. Because certain measurements are time consuming, the feedback control law is obtained in the presence of observation delay in some but not all of the system variables. The open loop optimal control is then found, showing explicity the effect of changes in any of the effluent sources on the aeration strategy. It is shown that the optimal strategy for a distribution of sources can be written as an affine transformation upon the optimal controls for sources of unit strength.
Lateral Dynamics Optimization of a Conventional Railcar
Authors: Cooperrider N. K. , Cox J. J. , Hedrick J. K.
Published: November 2010

The attempt to develop a railway vehicle that can operate in the 150 to 300-mph(240 to 480-km/h) speed regime is seriously hampered by the problems of ride comfort, curve negotiation, and “hunting.” This latter phenomena involves sustained lateral oscillations that occur above certain critical forward velocities and cause large dynamic loads between the wheels and track as well as contributing to passenger discomfort. This paper presents results of an initial effort to solve these problems by utilizing optimization procedures to design a high speed railway vehicle. This study indicates that the problem is more easily treated as a constrained optimization problem than as an unconstrained problem with several terms in the objective function. In the constrained optimization problem, the critical “hunting” speed was maximized subject to constraints on 1) the acceleration of the car body, 2) the suspension stroke length, and 3) the maximum suspension stroke while negotiating a curve. A simple, three degree-of-freedom model of the rail vehicle was used for this study. Solutions of this constrained problem show that beyond a minimum yaw stiffness between truck and car body the operating speed remains nearly constant. Thus, above this value, the designer may trade off yaw stiffness, wheel tread conicity and stability margin.
Simple Discrete Control of Industrial Processes (Finite Time Settling Control Algorithm for Single-Loop Digital Controller)
Authors: Takahashi Y. , Tomizuka M. , Auslander D. M.
Published: November 2010

Due to the rapid growth in LSI (large-scale integration) technology, it is now possible to consider implementing a discrete (digital) single-loop programmable controller. This paper discusses some software aspects of digital single-loop controllers for industrial processes. Based on the S-shaped response pattern typical in many industrial processes, a simple algorithm for a finite-time settling controller with an observer is proposed.
Simplification of High-Order Mechanical Systems Using the Routh Approximation
Authors: Hutton M. , Rabins M. J.
Published: November 2010

In many recent applications, the control engineer is faced with the problem of controlling a linear system modeled by a transfer function of high or infinite order. In a majority of these cases it is possible and advantageous to approximate the original transfer function by a transfer function of lower order. The Routh approximation is a novel method for reducing the order based on the idea of truncating the well-known Routh table used to determine stability—hence the name given to the method. The Routh approximants can be computed by a finite recursive algorithm that is suited for programming on a digital computer. The algorithm, flow diagrams, and simple numerical examples are presented. A detailed description of the theoretical background and properties of the method are given in [1] and [2]. This paper focuses on the application of the Routh approximation method and the simplification of two mechanical systems are described. First, a low order transfer function for studying vibration is computed from a finite element model of the structure. Second, the Routh approximation is utilized in the design of a thermal control system where the heat conduction is modeled as a distributed parameter system whose transfer function has infinite order.
An Efficient Simulation Method for Distributed Lumped Fluid Networks
Authors: Sidell R. S. , Wormley D. N.
Published: November 2010

A method is presented for the simulation of fluid networks consisting of uniform distributed elements and lumped dynamic, nonlinear elements. The uniform transmission elements may be lossy and dispersive. General relationships are derived for their terminations in junctions with other elements and/or with dynamic, nonlinear lumped elements. The basic computer simulation method is efficient in terms of computation time and core storage requirements in comparison to direct finite difference methods and may be implemented on a minicomputer. Simulation results are compared with experimental data for a pneumatic transmission line terminated with a nonlinear resistance and for a pneumatic transmission network consisting of three lines of incommensurate lengths.
Optimization of Automotive Engine Fuel Economy and Emissions
Authors: Prabhakar R. , Citron S. J. , Goodson R. E.
Published: November 2010

Curve fitting techniques are used to analytically represent experimental data on engine emissions as a function of engine operating variables. A model of the engine-vehicle system is formulated and the optimal control inputs for a given vehicle and specified test cycle are computed. Air-fuel ratio, spark advance, and exhaust gas recirculation are considered as the control variables. The results of the study indicate that considerable improvement over stock car performance can be obtained if the control variables are varied in an optimal manner over the driving cycle.
A Survey of Longitudinal Acceleration Comfort Studies in Ground Transportation Vehicles
Authors: Hoberock L. L.
Published: November 2010

Experimental studies of objective and subjective passenger response to various fore-and-aft, or longitudinal, vehicle acceleration transients are reviewed. It is found that the wide variability in type of study and form of results does not allow conclusive statements to be made regarding passenger acceptability of any specific acceleration—jerk profile in a given transportation system.
An Improved Symbolic Manipulation Technique for the Simulation of Nonlinear Dynamic Systems With Mixed Time-Varying and Constant Terms
Authors: Witham C. R. , Dubowsky S.
Published: November 2010

The time domain behavior of nonlinear dynamic systems often is obtained by numerical integration on the digital computer. These solutions are usually expensive and limit the scope of the dynamic study. The proposed improved technique results in a substantial increase in the computational efficiency by using automatic symbolic manipulation to generate explicit equations of motion algebraically prior to numerical integration. A model is presented which considers the effects of the presence of time-invariant and time-varying symbolic terms and of the sparsity of system elements to provide analytical guidelines for the use of this technique. A number of case studies including typical computational costs are presented.
Identification of Journal Bearing Characteristics
Authors: Burrows C. R. , Stanway R.
Published: November 2010

A new approach is proposed to the identification of the eight linearized coefficients which characterize the dynamics of a journal bearing oil-film. The use of pseudo-random binary forcing sequences is described together with cross-correlation and multiple regression analysis. The proposed technique is demonstrated by building a computer model of a rigid rotor running in plain journal bearings, based on Ocvirk’s short-bearing approximation. Multiple regression analysis is applied to the simulated data and the governing equations are reconstructed. In this way the advantages and limitations of the method are examined under controlled conditions.
Stochastic Linearization by Data Dependent Systems
Authors: Pandit S. M.
Published: November 2010

The paper presents and illustrates a method of stochastic linearization of nonlinear systems. The system response to white noise excitation is modeled by a differential equation, which provides the necessary transfer function. The linearization is optimal in the mean squared sense within the statistical limits imposed by the response. Since the linearization is accomplished purely from the response data, governing equations of the system need not be known. An application to machine tool chatter vibrations illustrates stability assessment and modal analysis. The ease with which optimal prediction and control equations can be derived and implemented is shown by an application to blast furnace operation. Detection and verification of limit cycles are illustrated by a model for airline passenger ticket sales data.
Micro-Machining of Copper and Aluminum Crystals
Authors: Von Turkovich B. F. , Black J. T.
Published: November 2010

The process of chip formation in copper and aluminum single crystals has been examined with a scanning electron microscope. The morphology of the shear planes clearly illustrates that the actual deformation zone (layer or shear front) is an extremely thin and well-defined band of slip planes wherein the predominant deformation takes place. The appearance of the top or upper surface of the chip corresponds to the micro mechanisms operating during the process of machining.
Upper Bound Solutions to Plane-Strain Extrusion Problems
Authors: Chen P. C. T.
Published: November 2010

A method for selecting admissible velocity fields is presented for incompressible material. As illustrations, extrusion processes through three basic types of curved dies have been treated: cosine, elliptic, and hyperbolic. Upper-bound theorem is used in obtaining mean extrusion pressures and also in choosing the most suitable deformation pattern for extrusion through square dies. Effects of die geometry, friction, and material properties are discussed.
A Method for Determining the Surface Contact Stresses Resulting From Interference Fits
Authors: Parsons B. , Wilson E. A.
Published: November 2010

A method is presented whereby the pressures, which are generated at the contact surfaces of two axisymmetrical components assembled together with an interference fit, can be determined. The approach of this method is to set up a series of influence coefficients for discrete matching nodal positions on the mating surfaces of the two components and to relate these by means of a matrix formulation, to the local nodal pressure and interference. Solution of the resulting set of linear simultaneous equations is readily performed by digital computer. The finite element approach for the determination of stresses and displacements in axisymmetrical components is used, in a somewhat modified form, to establish the influence coefficients at the surface of the outer component. While this same approach could be used for the inner component, in this present work, in order to emphasize the scope of the method, the inner component has been considered to be a solid shaft of infinite length for which influence coefficients derived from a “classical elasticity” approach can be used. Results are given for the pressure distribution along the contacting surface of a solid shaft when it is filled with axisymmetrical sleeves of various configurations—including rectangular, triangular, and stepped forms. The effect of using materials of different stiffness for the shaft and sleeve is analyzed, and the results obtained for the cases where the ratio of the material stiffness is very high and very low are compared with previously known solutions for these cases. The effect of using a varying interference is also considered. Full sets of computer programs, written in Fortran language, for each of the stages of the computation, together with detailed instructions for the compilation of input data, are presented.
Progress in Railway Mechanical Engineering, Cars and Equipment, 1968–1969
Authors: Bateson N. E. , Baker P. H. , Schulz F. W. , Manos W. P. , Shedd Tom
Published: November 2010

This paper contains the annual report of the ASME Survey Committee. Developments in Railway Mechanical Engineering from September 1, 1968, to September 1, 1969, 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, South America, Europe, and Australia is described and pictured.
The Effect of Disposable Load Drop on the Range of Aircraft
Authors: Thompson Milton J.
Published: November 2010

A simple analytical procedure is presented for the determination of the range or radius of action of an aircraft, based on the well-known Breguet equation, under conditions where a portion of the total payload, other than fuel, is to be dropped during the flight. It is assumed that this portion of the disposable load or dropped load is released at the mid point of the total distance flown. If the radius of action is compared with the value corresponding to no dropped weight being carried during the flight, the results may be normalized in terms of two weight parameters: (a) the ratio of the total disposable load of fuel and dropped load to the takeoff gross weight, and (b) the ratio of the dropped load to total disposable load. Numerical results are presented for a wide range in the values of these ratios disclosing some rather unique properties of the functional relationships involved. A comparison is made with the results of graphical determinations of bombing range, using methods originally presented by Diehl, it being shown that the present method agrees closely with Diehl’s approximate empirical relation for a limited range of the values of the weight parameters. The procedure described is equally adaptable to either propeller or jet-driven aircraft.
Influence of Lay Barge Motions on a Deepwater Pipeline Laid Under Tension
Authors: Brewer W. V. , Dixon D. A.
Published: November 2010

Tensioning is a prime requirement for laying deepwater pipelines. Of the several new or improved pipe laying methods which have been proposed, or even utilized, all require tensioning of the pipeline to minimize stress in the critical area. In these methods the use of a stinger is optional. Dixon and Rutledge produced charts by which the minimum tension and angle of inclination could be determined for laying pipelines in intermediate and deep waters. The pipeline is freely suspended from the sea floor up to the stinger, or to the lay barge if no stinger is used. It takes a shape over its unsupported length which differs from a natural catenary at its ends due to the pipeline stiffness. In the present work the authors have employed the same mathematical technique to study the sensitivity of a tensioned pipeline to lay barge motions, i.e., surge, heave, and pitch. Two general trends emerge from the results which are presented both in the form of graphs for several sizes of the pipeline and for water depths up to 1000 ft, and in the form of dimensionless charts. Surge, and to a lesser degree heave, is influential in shallow or intermediate water depths. Pitch becomes a critical parameter in deep waters where the tension is large. The influence of a sloping rather than horizontal sea floor is also studied in this work. It is shown that for a practical range of slopes the prior analysis gives a satisfactory description of the configuration. However, additional curves which have been provided are required to make application of the previous results.
Advance Biowaste Electric Propulsion Systems
Authors: Goodman M. , Yakut M. M.
Published: November 2010

This paper studies the vapor biowaste electric propulsion systems and the impact of the evolving advance life support oxygen recovery cycles and subsystem trade-offs on the biowaste expendable composition and mass balances. The results of a computer analysis of the potential performance of three representative compositions used as propellants in electrothermal thrusters are presented, including propellant specific impulse, chamber heating requirements, and electric power input needed for the attitude control of a typical 12-manned earth-orbiting space station. Reaction product compositions at various locations from chamber to plume are also presented.
Process Plant Noise Control at the Design Engineering Stage
Authors: Seebold James G.
Published: November 2010

Effective noise control actions have to be taken in the preliminary definition and engineering design stages of major capital projects. Government legislation and public sentiment have virtually eliminated “wait-and-see” as a viable alternative. Unfortunately, an adequate understanding of the design aspects of noise control in process plants currently exists neither for all important noise sources nor among all suppliers, contractors, and users. This paper discusses both solutions and problems in sections dealing with sound transmission outdoors, plant sound power, furnaces, air coolers, control valves, rotating machinery, piping systems, flares, correction versus design, specifications and guarantees. The contention is that, where it is lacking, an adequate understanding of noise generation can be achieved, leading to the design of plants that are adequately quiet from the start.
Analysis and Design of Ellipsoidal Pressure Vessel Heads
Authors: Esztergar E. P. , Kraus H.
Published: November 2010

The paper describes the development of design rules for 2:1 Ellipsoidal Heads. Elastic, elasto-plastic, and limit analysis results are evaluated to determine the lowest failure mode, including buckling under internal pressure. The numerical values of the failure pressure are compared with ASME Code requirements. It is shown that the code rules are overly conservative for thick heads and are unsafe for very thin heads used in low-pressure applications. A simple design formula is developed, based on rational safety factors, in a form adaptable for a pressure vessel code. The need for further work toward improved failure mode analysis is discussed.
Analysis of Stresses in Shallow Spherical Shells With Periodically Spaced Holes
Authors: Hulbert L. E. , Simonen F. A.
Published: November 2010

This paper concerns the numerical solution of shallow spherical shell problems by the method of boundary-point-least-squares. The analysis forms the basis of a computer program for the calculation of stresses in curved perforated plates. Multiple-pole series solutions are used, and recursion methods for generating the required Bessel-Kelvin functions are discussed. Numerical results are given for previously unsolved problems involving an array of seven circular holes and for an array of four noncircular holes.
Mobility Analysis of Plane and Spatial Mechanisms
Authors: Gupta Viney K. , Radcliffe Charles W.
Published: November 2010

A geometric method for the investigation of the mobility of plane and spatial mechanisms is presented. The mobility conditions are determined explicitly and displayed in the form of mobility charts.
A Computer Algorithm to Design Compound Gear Trains for Arbitrary Ratio
Authors: Dil Pare A. L.
Published: November 2010

A novel numerical method to determine the numbers of teeth in the driver and driven gears in a compound gear train is presented as an algorithm for computer-aided design applications. A brief review of available methods for double-pair gear sets is made, and compared to the proposed algorithm from the viewpoints of precision, computational efficiency, and ease of programming. In comparison, we now have for the first time completely eliminated dependency on tables of prime factors and conjugate fractions, and/or the ingenuity of the designer (albeit an interesting intellectual challenge), and reduced the problem to a direct, straightforward calculation as a self-contained algorithm easily programmed by the designer himself. The arbitrary irrational value of 1/π is used in a numerical example; sixteen candidate gear sets are obtained having an overall ratio within ±5 micro-units. The triple-pair gear set design problem is considered, and an extended form of the algorithm derived. This allows, also for the first time, the systematic design of a triple-pair gear set, and obviates heuristic or cut and try methods. The same value of 1/π is used in an illustrative example, and the results presented in tabular form.
On a Model of a Pneumatically Actuated Mechanical System
Authors: Skreiner M. , Barkan P.
Published: November 2010

A model of a general mechanical system, comprising a pneumatic system coupled to a linkage mechanism, is developed. The dynamic system behavior is studied using the digital computer as a design tool to determine the effect on the performance of changing design parameters. Within practical limitations, models of this kind have been used to achieve optimum design. Novel methods are used to treat the two major components of the system. The pneumatic system is modeled using an equivalent flow area which is a function of the time-dependent pressure ratio. Differential equations used to solve for the transient flow in the reservoir/piping/piston system are derived here. The mechanism driven by the pneumatic system consists of multiple series chains of four-bar linkages. The first- and second-order kinematic ratios required in the dynamics are computed from new explicit expressions derived here. Frictional losses, impact, and flexibility of the mechanism are included in the dynamic model. The nonlinearity of the differential equations arises from: (a) the kinematics, (b) drag forces depending on velocity squared, (c) magnetic forces depending on time squared, and (d) the strong nonlinearity of the time-dependent pneumatic system. The system of equations is solved numerically to obtain the record of pressure, temperature, and leakage in the pneumatic system and the travel of the mechanisms versus time. Good agreement is obtained between the theoretical solution and actual tests.
Nonlinear Dynamic Response of Elastic Slider-Crank Mechanism
Authors: Viscomi B. V. , Ayre R. S.
Published: November 2010

An investigation of the vibratory bending response of the elastic connecting rod of a slider-crank mechanism is presented. The response of the system is found to be dependent upon five dimensionless parameters. These are classified as the length, mass, damping, external piston force, and frequency parameters; and the effects of these parameters on the response of the system are investigated. The dynamic behavior is described as graphs of nondimensionalized deflection versus crank angle. Solutions of the linear as well as the nonlinear forms of the equations are included.
Dynamic Analysis of Mechanical Systems With Clearances—Part 2: Dynamic Response
Authors: Dubowsky S. , Freudenstein F.
Published: November 2010

The theory developed in Part I has been applied to the determination of the dynamic response of the Impact Pair under various operating conditions. Simulation techniques, as well as approximate methods used in control theory, have been used for this purpose.
Transverse Vibrations of a Centrally Clamped Spinning Membrane Disk
Authors: Krauter Allan I.
Published: November 2010

Axisymmetric and asymmetric vibrations of a membrane disk having a central hole and disk-central clamp friction are studied. It is shown that the vibration frequencies can be obtained by considering an equivalent disk having full central clamping.
Some Effects of Injecting Cutting Fluids Directly Into the Chip-Tool Interface
Authors: Sharma C. S. , Rice W. B. , Salmon R.
Published: November 2010

An experimental investigation in which SAE 1040 steel was cut orthogonally with fluid being forced directly into the chip-tool interface through a small hole in the rake face of the tool is described. Three fluids were used, a straight mineral oil, and the same oil containing either chlorine or sulphur. The distance of the hole from the tool tip was varied over a range of one to three times the depth of cut. Results indicate that cooling of the chip-tool interface by the injected fluid is of primary importance; and that blocking of the hole is a result of the breakdown of chloride and sulphide films caused by high temperature at the interface. An explanation of how the fluid escapes from the chip-tool interface is provided.
Prediction of the Geometry Changes of the Free Boundary During Upsetting by the Slip-Line Theory
Authors: Shabaik A. H.
Published: November 2010

Local values of shear stress at the tool-workpiece interface in plane-strain upsetting were determined from experimental observation of the distorted grid pattern. The friction condition at the interface was formulated and used to develop the slip-line net. This slip-line net was used to predict the geometry changes of the free boundary. Results of this method showed good agreement when compared with those obtained experimentally. Using Hencky’s equations, the normal pressure was determined at the interface. From the normal pressure values, the load was calculated and compared to that measured during experiment.
Stochastic Model for Machining Processes—Optimal Decision-Making and Control
Authors: Wu S. M. , Dalal J. G.
Published: November 2010

An automatic screw machine process is used as an example to investigate machining operations. Experiments were conducted and a stochastic model for the time series on observed performance of the machine was identified. With the stochastic model, it is possible to forecast the future performance. A simple cost model is assumed for the machining operation and an operating criterion of minimum expected cost per period of operation is used to determine the optimal operating policy. A rolling policy method was used to obtain the optimal operating policy for an indefinite planning horizon. The automatic screw machine process was simulated on a digital computer to determine its performance. The stochastic portion of the deviations from the target was corrected, and the extent of correction was shown to be determined by the cost parameters.
Application of a Disorder Measure to Acoustical and Structural Models
Authors: Lyon Richard H.
Published: November 2010

The interaction of structures and sound fields frequently involves many degrees of freedom of each participant in a complicated interaction process. In one way or another, statistical or deterministic models of the systems involved are applied in such problems and the resulting vibration (or radiation) is calculated, frequently to a satisfactory degree of accuracy. At other times, however, the results of these calculations suggest that a statistical rather than deterministic model might have been more satisfactory (or vice versal). What is clearly lacking is an a priori criterion for deciding whether a statistical or deterministic model of a system/response situation is more appropriate. The purpose of this paper is to discuss the manner in which a measure of disorder similar to those employed in other areas of technology might be calculated for problems in sound and vibration.
Procurement of Safe Viewports for Hyperbaric Chambers
Authors: Stachiw J. D. , Gray K. O.
Published: November 2010

Lack of ASME Pressure Vessel Code Standards for the selection of material, designs, fabrication techniques, and prooftesting methods for viewports in hyperbaric chambers makes it mandatory that engineering judgment be exercised to the fullest in the procurement of such viewports. Based on the experience gained by the authors in past experimental programs dealing with design criteria, and procurement of acrylic viewports for major Navy hyperbaric chamber installations, practical guidelines are proposed for specifying such viewports. The guidelines contained in this paper address themselves to selection of viewport shape, safety factor, material, fabrication, quality control, proof-testing, and periodic inspection.
Stress Concentration in a Cylindrical Shell Containing a Circular Hole
Authors: Adams N. J. I.
Published: November 2010

The state of stress in a cylindrical shell containing a circular cutout was determined for axial tension, torsion, and internal pressure loading. The solution was obtained for the shallow shell equations by a variational method. The results were expressed in terms of a nondimensional curvature parameter which was a function of shell radius, shell thickness, and hole radius. The function chosen for the solution was such that when the radius of the cylindrical shell approaches infinity, the flat-plate solution was obtained. The results are compared with solutions obtained by more rigorous analytical methods, and with some experimental results. For small values of the curvature parameter, the agreement is good. For higher values of the curvature parameter, the present solutions indicate a limiting value of stress concentration, which is in contrast to previous results.
Fatigue Crack Growth in Type 316 Stainless Steel at High Temperature
Authors: Shahinian P. , Smith H. H. , Watson H. E.
Published: November 2010

The dependence of fatigue crack growth rates on range of stress intensity factor (ΔK) in Type 316 stainless steel was investigated over the temperature range of 75 to 1100 deg F. The data for the most part could be described by a power law relationship. An increase in temperature generally increased crack growth rate for a given ΔK and decreased fatigue life. The dependence of crack growth rate on temperature is not described adequately by an Arrhenius relation over the range investigated. On the other hand, by normalizing ΔK with respect to Young’s modulus, E, the crack growth rates for the various temperatures tend to fall within a single band.
Radiation and Response of Cylindrical Beams Excited by Sound
Authors: Bailey J. R. , Fahy F. J.
Published: November 2010

The sound radiated from an unbaffled cylindrical beam vibrating transversely at resonance is calculated by solution of the classical wave equation subject to the boundary conditions imposed by the motion of the beam. The interaction of sound and vibration is then demonstrated by using a theory based on the principle of reciprocity to predict the resonant response of a cylindrical beam to acoustic excitation. The results show that radiation and resonant response are highly frequency dependent. An experimental program is also reported. The power radiated from three cylindrical beams vibrating at resonance and the resonant response of the beams to pure-tone acoustic excitation are measured in a reverberation chamber. The experimental results agree well with the theoretical predictions.
Coupled Response of Spatial Vibratory Structures Mounted to Isotropic Plate Elements
Authors: Saczalski K. J. , Huang T. C.
Published: November 2010

Compatibility and modal coupling, using Lagrangian multipliers as coupling mechanisms, establishes the dynamic influence of isotropic flat plates on spatial vibratory structures containing arbitrary shaped rigid bodies. The elastodynamic Euler-Lagrange equations of equilibrium and compatibility are developed and resolved into matrix form to provide a convenient format for describing deterministic and nondeterministic response characteristics of the coupled system. The resulting vibration problem is solved by classical transform methods for free and forced vibration excitations. Special cases of randomly excited systems round out the nondeterministic statistical applications. A particular example illustrates the application of analysis.
The Effect of Liquids on the Dynamic Motions of Immersed Solids
Authors: Fritz R. J.
Published: November 2010

It is known that the presence of liquids can significantly affect the dynamic motions of immersed solids. This paper proposes a method for evaluating fluid forces for use in the dynamic analysis of moving systems in which solid bodies are completely immersed in incompressible, frictionless fluids. A damping parameter is suggested to determine whether a fluid system may be considered frictionless. The incompressibility requirement is also discussed. Experimental data are cited to support the proposed method. Formulas for hydrodynamic masses are tabulated.
A Note on the Calculation of Torsional Natural Frequencies of Branch Systems
Authors: Gilbert A. C.
Published: November 2010

An adoption of matrix techniques is proposed as a method for the solution of torsional natural frequencies in a branch or geared shaft system. Both fundamental and higher mode shapes and frequencies are produced by a comparatively rapid and straightforward technique. The method is illustrated by a numerical example of a coupled turbine and reciprocating engine system driving a common propeller.
Axial Vibration Transmission Characteristics of Shells of Revolution
Authors: Wilson C. E. , Curreri J. R. , Koplik B.
Published: November 2010

Transmission of vibration by shells of revolution is investigated, with particular emphasis on the effects of shell mass and thickness, internal damping, and edge restraint. Numerical results are given for the truncated conical shell where harmonic axial excitation is assumed at one shell edge, resulting in a harmonic axisymmetric response. Input-response relationships are described by a four element transfer matrix relating force and displacement amplitudes. The matrix elements are obtained by superposition of the results of simultaneous numerical integrations of the shell equations. The results are applied to the case of a conical shell supporting a rigid mass.
Analog and Digital Analysis and Synthesis of Oscillatory Tracks
Authors: Mansour W. M.
Published: November 2010

A vibratory feeder is essentially an inclined plane which is subjected to an acceleration cycle. It is used to transport components or material, after giving them the proper orientation or mixing. Usually rapid upward motion is desired. The purpose of this paper is to provide the designer with some basic tools that enable him to analyze, and effectively choose, the basic parameters pertaining to a vibratory feeder. Programs to solve specific cases are also included. The digital and analog approaches are used with equal emphasis whenever applicable.
Upper-Bound Solutions to Tube Extrusion Problems Through Curved Dies
Authors: Chang K. T. , Choi J. C.
Published: November 2010

Velocity fields of tube extrusion problems through curved dies are presented for an incompressible material. These velocity fields are also applicable to conical and square-cornered dies. Thus, in principle, upper bound solutions for tube extrusion problems through arbitrarily shaped dies are obtained. As an illustration, tube extrusion processes through conical dies of small cone angle have been treated. Effect of die geometry and friction is presented graphically.
On the Metal Physical Considerations in the Machining of Metals
Authors: Ramalingam S. , Black J. T.
Published: November 2010

Experimental studies of plastic deformation produced during metal cutting have shown that a dynamic equilibrium is established between strain hardening and recovery during chip formation. Recrystallization studies on interrupted cut specimens show that the chip is formed by shear on a thin plane or surface which segments the chip into a lamella structure. Scanning and transmission electron microscopy studies on the lateral surfaces of prepolished interrupted cut specimens substantiate the evidence obtained from the recrystallization studies. The chip formation process has thus been found to be strongly sensitive to the metal physics and defect strticture of the material undergoing plastic deformation. The important variables involving dislocation interactions during chip formation are the number and orientation of operable slip systems, certain characteristic dislocation parameters such as stacking fault energy, the interaction of dislocations with vacancies and solute atoms or with second phase particles (both coherent and noncoherent types), the short and long range order of the material, and the temperature of the deformation, all of which affect the strain hardening behavior of the material. In addition, those factors which govern the kinetics of dynamic recovery such as outright collision of dislocation segments, cross slip, and climb induced by a supersaturation of point defects produced in the course of deformation must be considered.
Diamond Bit Drilling Research
Authors: Dellinger T. B. , Livesay B. J.
Published: November 2010

Fundamental relationships of the parameters; penetration rate, bit weight, rotary speed, bit horsepowers, flow rate, and pressure were developed using eight full-scale, oilfield diamond drilling bits under laboratory-controlled conditions. One thousand five hundred data points, with all the parameters, were analyzed with 642 plots and 131 multiple-regression analyses. The hydraulic lift under the diamond bit has been accounted for in order to obtain relationships of mechanical bit weight with torque and penetration.
Computer-Aided Synthesis of Mechanisms Using Nonlinear Programming
Authors: Gupta V. K.
Published: November 2010

The synthesis of spatial mechanisms is formulated as a mathematical programming problem and solved using a penalty function approach. The objective function as well as the equality and inequality constraints are determined explicitly from conditions such as those required for linkage closure, mobility, and transmissibility.
A Finite Element Based Procedure for Simulating the Transient Response and Failure of a Two-Dimensional Continuum With Nonlinear Material Characteristics
Authors: Wallace D. B. , Seireg A.
Published: November 2010

This paper presents a finite element based procedure for the analysis and graphic display of the response and failure patterns of a two-dimensional continuum subjected to impulsive loading. Elastic, anelastic, plastic and other nonlinear material properties and failure theories can be incorporated in the analysis. The procedure is illustrated by examples of elastic and anelastic impact of solid and hollow cylinders. The developed technique gives a powerful tool for the evaluation of transient stresses, deformations, yield and fracture modes in two-dimensional continuum with arbitrary geometry and nonlinear properties.
The Design of a Linear “Out of Phase” Vibratory Conveyor
Authors: Schofield R. E. , Yousuf M.
Published: November 2010

This paper describes the development of a linear “out-of-phase” vibratory conveyor. The “out-of-phase” effect is achieved by controlling the components of motion normal to and parallel to the track independently. This is done by mounting the trough on sets of double “U” shear rubber mountings. From Fig. 1(a) it can be seen that these mountings allow motion in any direction in the plane of the rubber while substantially constraining motion perpendicular to that plane. Excitation of the trough is by two hydraulic pumps the phase angle between which is controlled by a positive drive belt. Experimental investigations into the behavior of single parts were carried out and results comparable to the theoretical predictions for “out-of-phase” were obtained. Substantial increases in the mean conveying velocity of single parts can be achieved without erratic part movement because it is possible with this system to use high values of normal track acceleration An/g combined with low vibration angles. Increases in mean conveying velocity of as much as 270 percent are obtained, depending on the coefficient of friction and vibration angles.
The Mechanism of Gyroscopic Tracking: Part 2
Authors: Mansour W. M. , Pavlov D. , Dokainish M. A.
Published: November 2010

A parametric study is conducted to assess the effect of different factors on the tracking performance. The conditions leading to the free flight mode are established. Design recommendations and proposed applications are presented.
Kinematic Analysis of Plane and Spatial Mechanisms
Authors: Gupta V. K.
Published: November 2010

A method is presented for the investigation of the kinematics of plane and spatial mechanisms. The kinematic analysis solutions are determined explicitly from the geometric constraints associated with particular links in the mechanism.
Kinematic Synthesis of Cam Profiles for Prescribed Acceleration by a Finite Integration Method
Authors: Chen F. Y.
Published: November 2010

In this paper, a new numerical method of finite integration is introduced for synthesizing the cam profile for arbitrarily prescribed acceleration curves. The method is compared with the conventional method of finite-differences, and it is shown that the proposed method is of superior accuracy and is believed to be suitable for high speed profiles. Numerical examples are given.
Design of Spherical Crank-Rocker Mechanism With Optimum Transmission
Authors: Bagci Cemil
Published: November 2010

Spatial and spherical mechanisms must not be designed for optimum transmission characteristics as plane mechanisms. The transmissivities and transmission angles in spatial and spherical mechanisms are determined by the skew angles between the pair axes on the links. A spherical crank-rocker mechanism is optimized to satisfy a prescribed advance-to-return time ratio and to have an optimum torque-to-torque transmissivity. Design equations and some illustrative design tables are given. It is illustrated that a spherical mechanism optimized as a plane mechanism may be a structure. A graphical method of designing spherical crank-rocker mechanisms, using stereographic projections, is also presented.
Degrees of Freedom and Constraints in Geared and Belted Mechanisms
Authors: Bagci Cemil
Published: November 2010

Further application of the general form of the mobility equation in identifying geared, belted, and chained mechanisms correctly, and in determining degrees of freedom in these mechanisms is illustrated. It is shown that the pair (gear tooth pair—GT) at the point of contact of two mating gears is a class 1 pair; a loop formed by gear members, in which the center distance does not vary, experiences over closure of order one; loops including a belt and pulley, or a chain and sprocket, have the same properties as those including a gear and rack. Several planar, spherical, and spatial geared and belted mechanisms and cam mechanisms are tested for their mobility.
The Automatic Generation of a Mathematical Model for Machinery Systems
Authors: Smith D. A. , Chace M. A. , Rubens A. C.
Published: November 2010

This paper presents a detailed explanation of a technique for automatically generating a mathematical model for machinery systems. The process starts from a relatively small amount of input data and develops the information required to model a mechanical system with Lagrange’s equation. The technique uses elements of graph theory which were developed for electrical networks. The basic identifications required for mechanical systems are: paths from ground to mass centers, the independent loops of parts, if any, and paths associated with applied force effects. The techniques described in this paper have been used successfully in a generalized computer program, DAMN.
Synthesis of Kinematic Chains via Method of Cut-Set Matrix With Modulo-2 Operation
Authors: Huang M. , Soni A. H.
Published: November 2010

Method of cut-set matrix with modulo-2 operation is used to enumerate all possible tree graphs from a given tree graph. The typical kinematic chains corresponding to the tree graphs are the chains with cams and gears. The equations used to find the number of heavy edges (corresponding to cam or gear joints) and fine edges (corresponding to turning joints) required in the tree graphs are presented. A table of tree graphs and their corresponding cam kinematic chains is prepared. The method is potentially promising for computer-aided design application because of its simplicity, compact notation, and high degree of organization.
Closed Form Displacement Relationships of Single and Multi-Loop Six-Link Spatial Mechanisms
Authors: Soni A. H. , Dukkipati R. V. , Huang M.
Published: November 2010

Using (3 × 3) matrices with dual elements, two loop Watt and Stephenson type six-link spatial mechanisms with one revolute and six cylinder pairs and single loop R-C-R-R-P-R, R-C-R-R-R-R six-link mechanisms are examined to obtain closed form displacement relationships between independent and dependent displacement parameters. Displacement analyses are performed to illustrate the use of these displacement relationships.