bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fluidic Load Cell
Authors: Drzewiecki Tadeusz M.
Published: November 2010

A possible fluidic load cell design consists of three parts: a structural member that deforms linearly with load, a fluidic strain gage having fluidic resistance that changes with deformation, and a three-stage laminar proportional amplifier-gain block that amplifies the change in strain gage through-flow to useful levels. This Technical Brief presents design relations for the first two parts of such a system. Two compressive load cells were built, incorporating different fabrication techniques and deformation-sensing methods. The loading range of these cells is about 0 to 20 kN (0 to 2 tons) with a dynamic range greater than 100 and a typical full-scale output pressure of 30 pascals (4 × 10−3 psi). Possible applications for fluidic load cells include force measurements in highly incendiary or radiative environments and/or when other fluid control circuitry is used.
A New Performance Index for Improved Computer Aided Design of Control Systems
Authors: Martens H. R. , Larsen G. R.
Published: November 2010

A new performance index for the computer aided design of control systems is developed. The index is structured to force the design of the control systems into a region of the design space relating to acceptable system specification: The design process converges to a feasible region in which all of the performance requirements have been satisfied. The performance specification index was developed specifically for systems requiring a steady state response after a given time interval. The CAD process utilizes the Davidon-Fletcher-Powell Optimization Method in conjunction with State Transition and Runge-Kutta-Merson simulation techniques to obtain discrete and continuous time system designs, respectively. The procedure determines DDC and PID parameters by minimizing specified performance violations. Examples of the discrete and continuous time system performance specification designs are compared with conventional ISE design results.
Input-Output Stability Criteria for a Broad Class of Stochastic Nonlinear Distributed Systems Defined by Green’s Function
Authors: Jumarie G.
Published: November 2010

This paper deals with the input-output stability of a class of nonlinear distributed systems defined by their Laplace-Green’s functions, or similarly from a practical point of view, by their distributed transfer functions. The time dependent nonlinear feedback element is distributed and bounded by two limiting gains which depend explicitly upon the distributed parameter. These systems are disturbed by a state and space dependent Gaussian noise which is added to the input of their linear components. This noise depends explicitly upon the output of the system via its own nonlinear feedback gain. Some input-output stability criteria are stated, which can be considered as being stochastic distributed versions of the circle criterion available for deterministic lumped parameter systems. They involve the stochastic mean square norm and they are expressed in term of the relative positions, in the complex plane, of a circle which depends upon the nonlinearities and the variance of the noise on the one hand; and a locus which may be interpreted as being the Nyquist locus of the linear part on the other hand.
Dynamics of the Human Kip-Up Maneuver
Authors: Ghosh T. K. , Boykin W. H.
Published: November 2010

Results of experimental and analytical investigation of a human motion problem are presented. Kip-up maneuvers by a human performer are recorded photographically. A three rigid link model is constructed for the performer using Hanavan’s inertia model of a human being. Comparisons of the observed motion with solution of the mathematical model equations are presented. A “minimum-time” performance of the performer is then compared with an approximate analytic solution for the three link model. Differences between the observed motions and the analytical solutions are discussed. Some changes in the model are suggested.
Critique of a Large-Scale Organ System Model: Guytonian Cardiovascular Model
Authors: Sagawa K.
Published: November 2010

This paper reviews Guyton’s model which is large not only in the number of its components but also in the time scale that it spans. The evolution of this model is explained in three stages. Guyton started with a drastically simplified model of the entire cardiovascular system as a closed hydraulic loop. It accounted for short-term regulations of cardiac output with a special emphasis on the role of blood volume and the vascular capacity. Guyton’s research objective was then directed toward the analysis of longterm regulation of arterial pressure. Two slowly acting mechanisms were considered as particularly important: (1) the marked increase or decrease of urinary output with only slight increase or decrease in arterial pressure (the renal function curve in the Guytonian model) and (2) long-term vascular autoregulation which includes changes in the extent of vascularization as well as constriction or dilation of existing vessels to match the blood flow with the oxygen demand in tissues. This second-stage model explained the transient dynamics and steady equilibrium of renal hypertension. The current version of Guyton’s model incorporates a variety of additional endocrine and neural mechanisms which parametrically control the renal function curve. With the enormous growth, the identification (or estimation) capability of the model is bound to degrade while its use for multiple parameter sensitivity tests expands. The modeller’s group has attempted to minimize the hazards by frequent checks of model predictions with experimental studies. This interactive effort, plus their concern over these long-term regulatory mechanisms, make the Guytonian model a unique venture in modern cardiovascular physiology.
Modeling Studies of the Dynamic Control of Hepatic Glucose Balance
Authors: Bergman R. N. , El Refai M.
Published: November 2010

The survival of mammals is dependent upon a relatively constant, adequate supply of glucose to the central nervous system, despite large fluctuations in the amount of food available. When food is abundant, the liver stores ingested carbohydrate as glycogen, and during fasts, the stored glycogen is released at a precisely regulated rate to maintain the blood glucose level. The rates of storage and release of carbohydrate by the liver are determined by the plasma concentrations of several bloodborne signals; most important are the concentrations of glucose, and the hormones insulin and glucagon. To understand the complex control relationships of these three signals as they affect the liver, their individual dynamic influences have been determined experimentally, and they have been integrated by means of a computer simulation of the pathways of hepatic glycogen metabolism. The simulation studies have led to specific hypotheses about the biochemical effects of glucose and insulin on the liver. The simulation studies have also led to the conclusion that glucose exerts a rapid moment-to-moment influence of glucose on the rate of uptake of glucose by the liver. Insulin, however, by exerting a slower influence on the sensitivity of the liver to glucose, is very effective in “optimizing” the amount of glycogen which the liver stores food during food intake. Thus, integrated experimental and simulation studies can lead to a view of a physiological regulating system which does not emerge from either approach used alone.
Plenum Air Cushion/Compressor-Duct Dynamic Interactions
Authors: Sweet L. M. , Richardson H. H. , Wormley D. N.
Published: November 2010

An analytical model for the static and dynamic behavior of plenum-type air cushion suspensions, including compressor and feeding duct interactions, is developed and experimentally verified. Conditions for cushion instability (flutter) are identified and stable and unstable operation is demonstrated both analytically and experimentally. Step response tests conducted by dropping experimental scale model suspensions from heights up to 1.75 times the equilibrium hover height show that a linearized model accurately predicts the experimental response, including sprung and unsprung mass natural frequencies and damping ratios. Criteria are given for selection of low-order dynamic models, based on product expansions, for the distributed parameter feeding duct. It is shown that cushion-duct dynamic interactions may strongly affect cushion stability unless the lowest duct resonant frequency is substantially higher than the suspension sprung and unsprung mass natural frequencies.
A New View of the Modal Control Technique
Authors: Ju H. , Rabins M. J. , Han C. D.
Published: November 2010

The well-known modal control technique has been reviewed and a new computational approach been developed. Unlike other methods, this approach is both nonrecursive and independent of the relative dimensions of the state, input, and output vectors. Also a companion modal feedforward controller is developed to compensate for measured disturbances. The development of the method is presented along with comparison to previous computational approaches. Application of the method is tested on a simulation of a complex dynamic system, and numerical results are discussed.
The Effect of Elevated Guideway Construction Tolerances on Vehicle Ride Quality
Authors: Hedrick J. K. , Ravera R. J. , Anderes J. R.
Published: November 2010

In this paper the ride quality of a vehicle traversing an elevated guideway is related directly to guideway construction tolerances and design parameters. Moreover, the construction tolerances are modeled in terms familiar to a guideway contractor. The tolerances modeled for an elevated, two-span semicontinuous, concrete guideway are: surface finish, camber deviations, pier survey errors, and pier settlement. The major design parameters relating to live-load deflection, stiffness (material and cross-section), and pier spacing are included. A general technique is presented for relating these tolerances to vehicle ride quality by means of a digital computer simulation. Various ride quality criteria are considered, including rms acceleration, acceleration spectral density, acceleration frequency decomposition, and a deterministic state space boundary. Numerical results are presented for a particular vehicle-guideway configuration and as such are valid only for the system considered. It is shown that for this system, equivalent ride quality can be maintained while adjusting the various construction tolerances. This trade-off capability allows the contractor to choose the least costly combination of tolerance parameters.
System Properties of One-Dimensional Distributed Systems
Authors: Bonderson L. S.
Published: November 2010

The system properties of passivity, losslessness, and reciprocity are defined and their necessary and sufficient conditions are derived for a class of linear one-dimensional multipower distributed systems. The utilization of power product pairs as state variables and the representation of the dynamics in first-order form allows results completely analogous to those for lumped-element systems.
Lagrange’s Equations for Complex Bond Graph Systems
Authors: Karnopp Dean
Published: November 2010

The standard means of imposing causality to extract state equations for bond graph models of physical systems can be inconvenient when algebraic loops and derivative causality in combination with nonlinear constraints are present. This paper presents an alternative means of writing system differential equations using energy and coenergy state functions and Lagrange’s equations. For certain types of systems, particularly mechanical and electromechanical systems, this indirect means of finding state equations turns out to be very convenient. In this technique, causality is used in a new way to establish generalized coordinates and generalized efforts for nonconservative elements. Finally, it is shown that in some cases in which a Lagrangian can be written by inspection for a complex mechanism, a detailed bond graph for this component is unnecessary and yet the equations of the mechanism can be easily coupled to the bond graph equations for the remainder of the system.
Shear Stress in Metal Cutting
Authors: Von Turkovich B. F.
Published: November 2010

Since the shear stress is the main parameter influencing the energy requirement in machining, the estimation of this stress remains one of the principal problems in the theory of chip formation. An insight in the behavior of the shear stress can be obtained by considering the process of plastic deformation from the viewpoint of dislocation theory. The theory is developed for high strain rate processes and very large strains.
The Offset Torsion Bar
Authors: Fazekas G. A.
Published: November 2010

The offset torsion bar is shown to generate a load versus torsional deflection characteristics similar to that of Belleville Springs.
Finite Kinematic Synthesis of a Cycloidal-Crank Mechanism for Function Generation
Authors: Kramer S. N. , Sandor G. N.
Published: November 2010

The method of complex numbers is applied towards the kinematic synthesis of a planar geared five-bar cycloidal-crank mechanism for approximate function generation with finitely separated precision points. It is shown that up to 10 precision points can be obtained, and a closed-form solution is presented which yields up to 6 different mechanisms with a 6-point approximation. In this method, the designer has control over the design of the cycloidal crank regarding gear ratio and configuration. The method has been programmed for automatic digital computation on the IBM-360 system, and the program is made available to interested readers. An optimization method utilizing iterative application of the closed-form solution is outlined.
Selection of Sampling Parameters for Modeling Grinding Wheels
Authors: Deutsch S. J. , Wu S. M.
Published: November 2010

Autoregressive-moving average models are developed to represent grinding wheel profiles for different combinations of sampling parameters including the sample interval, the number of observations, and the length of record. Using 46 and 120 grit grinding wheels, the effects of the choice of sample interval and number of observations on the appropriate model form are investigated. Discrimination between models for different grit size grinding wheels is discussed. A new criterion is proposed for the selection of the sample interval, based on observations per grit (OPG), to achieve comparable discrete approximations of the wheels and to maximize discrimination between models of different wheels.
The Effect of Parameter Variations in Precision Grinding
Authors: Lindsay Richard P.
Published: November 2010

Introduction of the metal removal and wheel wear parameters enable the basic linear laws of grinding to be established. The effects of diamond dressing and wheelspeed upon the metal removal parameter, surface finish, and workpiece geometry are described. Since in a production cycle these outputs are also affected by workpiece hardness and stock conditions, procedures are described whereby each influence may be studied separately and in combination. Finally a method is described which, when applied to a production cycle, compensates for these variations and results in more consistent output quality, with a higher probability of meeting tolerance specifications.
A Statistical Analysis of Rod Pump Maintenance
Authors: Rollings R. E. , Jensen P. A. , Wagner G. R.
Published: November 2010

This paper explains the development of a decision tool to assist in determining if investments should be made to replace rod pumps which have failed in marginal oil wells. The paper is concerned with satistically forecasting the economic parameters of payout, rate of return, and total oil and equivalent gas produced between failures, using regression analysis and Monte Carlo simulation.
Contributions to the Determination of the Equations of Motion for Multidegree of Freedom Systems
Authors: Maros Desideriu , Orlandea Nicolae
Published: November 2010

This paper is a further development of the kinematic problem presented in our 1967 paper [1] in which we have obtained the transmission functions for different orders of plane systems with many degrees of freedom. This paper establishes the corresponding system of differential equations of motion beginning with these functions. The purpose of this paper is to facilitate computer programming. Our study is based on the work of R. Beyer [2, 3] and is the first original addition to his papers. A second original contribution to Beyer’s theories is the deductive method of solution, from general to particular, which we have, incorporated in our work. Beyer concluded that the cases having two or three degrees of freedom can be considered as particular solutions to the results obtained.
Roberts’ Cognate of Space Five-Link RHHHH and HHRHH Mechanisms
Authors: Soni A. H. , Pamidi P. R.
Published: November 2010

Using the principle of similarly varying triangles, the existence of the coupler cognate of space five-link RHHHH and HHRHH mechanisms is established for the general case in which the coupler point is arbitrarily located in the plane of one of their coupler links.
Coupler Cognates of Eight-Link Mechanisms With Ternary Links and Double Joints—Part 2
Authors: Soni A. H.
Published: November 2010

Using the principle of stretch rotation and the principle of similarly varying triangle, the existence of coupler cognates of eight-link mechanisms with ternary links and double joints is established. It is shown that there are two additional stationary pivots; each of these stationary pivots yields an infinite number of cognate mechanisms for a given source eight-link mechanism.
The Towne Lecture: The Price of Success—Management Leadership in a Pluralistic Society
Authors: Drucker Peter F.
Published: November 2010

Management has been the “success story” among social institutions in this century. And, because of its success, it is now being asked to take on a new role—that of integrator, leader, and conscience of the interests and needs of the community in a new pluralistic society.
A Concept of a Plan
Authors: Grogan George C.
Published: November 2010

A concept is presented wherein an elemental plan is comprised of seven distinct, but inseparable, dimensions. Various partial combinations of these dimensions are shown to connote familiar management terms. The process of constructing a multidimensional plan is described, including internal consistency checks and documented formats. Speculation on future planning needs concludes the paper.
A System of Specification of Lathe Tool Nomenclature
Authors: Luk W. K.
Published: November 2010

From the mechanics of turning operation, a system of specification of lathe tool nomenclature is derived. The system also satisfies the criteria of ease of grinding and ease of inspection.
The Damping Effects of Viscoelastic Materials: Part 2—Transverse Vibrations of Plates With Viscoelastic Coatings
Authors: Pearce Britt K. , Baumgarten Joseph R.
Published: November 2010

An energy method is employed to analyze a nonhomogeneous, damped plate composed of an elastic (metal) layer and an unconstrained viscoelastic layer. This analysis is limited to the case of thin plates subject to no constraints and vibrating freely in the fundamental mode. The theory developed enables one to predict the damped natural frequency and the rate of decay (in terms of logarithmic decrement) of the transverse vibrations of a composite plate of given dimensions and composed of two particular materials. Experimental measurements bear out the fact that theoretical predictions are indeed accurate. Plates with two symmetric viscoelastic coatings are also considered and their damping effects are compared to those of coatings applied to one side only.
Analysis and Design of Multistage Torsion Springs
Authors: Libman H. , Shaanan S.
Published: November 2010

An experimental and theoretical study of a “multi-stage torsion spring” is presented. The spring is designed for high torsion (25 kg-m), considerable angular displacement (±20 deg), space limitations, considerable service life, linearity, and hysteresis restrictions. Theoretical and experimental data are found to be in very close agreement.
Optimum Design of Prismatic Bars Subjected to Longitudinal Impact
Authors: Wallace D. , Seireg A.
Published: November 2010

This paper presents a procedure for the automated selection of the configuration of stepped prismatic bars placed between given hammers and anvils to produce maximum force amplification or attenuation. A relatively economical computer scheme has been developed for the analysis of the wave propagation in bars with step changes in impedance. The procedure is utilized in an automated system for the optimum design of such bars.
Optical Properties of a Spherical Plastic Underwater Observatory NEMO
Authors: Trowbridge Taylor
Published: November 2010

The optical effects occurring during observation from within a transparent spherical underwater observatory are analyzed. Quantitative results are presented for the NEMO observatory. These results include location, size, and shape discrepancies for the entire range of possible object locations, for the entire range of possible eye locations, and for “best” and “worst” cases of eye orientation. Results were obtained from ray tracing computed in accordance with Snell’s law by using an iterative numerical procedure. The distance and size discrepancies were found to be severe; however, the distortions in shape and the discrepancies in the subtended angles were remarkably mild. It may be that for reasonable eye locations, observations in all directions from spherical observatories will present a much more realistic scene than observations through a planar interface, even for viewing normal to the planar interface.
Nonlinear Deformation of a Pressure Diaphragm in Contact With a Piston
Authors: Soedel Werner , Cohen Raymond
Published: November 2010

The problem of a shallow shell of revolution type diaphragm experiencing large deflections while being in contact with a centrally located piston is solved for some typical cases of pressure-displacement converter designs. The configuration and size of the contact area between diaphragm and piston is pressure dependent. Marguerres equations were assumed to be applicable and were solved by successive integration. The piston is assumed to be rigid, but supported by a linear spring.
Underwater Behavior of Free-Flooded Ceramic Ring Transducers
Authors: Wilkinson J. P. D. , DaCosta M. J.
Published: November 2010

A numerical method is presented for the study of the underwater behavior of piezoelectric ceramic transducers in the shape of a shell of revolution, which are known as free-flooded ring transducers. The ceramic is circumferentially polarized and may be prestressed circumferentially by a layer of fiberglass. The method computes stresses within the transducer, its electrical admittance, and the acoustic radiation pressure field in the water. The theory is compared with experimental results from a circumferentially polarized PZT-4 cylindrical ring, and good agreement is obtained.
Stress Resultants and Out-of-Plane Deformations in Stiff Rings Attached to Elastic Cylinders and Subject to Concentrated Loads
Authors: Shaffer Bernard W. , Ungar Eric E.
Published: November 2010

Expressions are derived which give the internal loads and deformations of a relatively stiff ring which is mounted on an elastic cylinder. Three basic types of loads acting on the ring are considered: a concentrated force acting in the direction parallel to the axis of the cylinder, a bending moment acting about a radial axis, and a bending moment acting about a tangential axis. The entire problem is first analyzed for the general case in which the centers of twist of the ring cross sections do not coincide with the mid-surface of the cylinder, and then also developed for the special case where these do coincide. An illustrative example is presented which gives an indication of the effect of the lack of coincidence of the centers of twist of the ring and the cylinder mid-surface.
The Transient Character of the Near-Field Acoustic Radiation From a Cylindrical Diaphragm Excited by Water Hammer Transients
Authors: Davis B. W. , Weynand E. E.
Published: November 2010

An investigation of the transient character of the near-field acoustic radiation from a water hammer excited, cylindrical diaphragm was conducted. The investigation was principally experimental and focused on relating the radiated waveforms to pressure transients within the pipe. The basic experimental system consisted of a length of rigid pipe extending from a flow source into a large sonar tank. The rigid pipe was interrupted by a cylindrical section of elastomeric tubing which served as a diaphragm and, thus, as an acoustic coupler between the water inside the pipe and water surrounding the pipe. A quick-closing valve downstream of the diaphragm produced water hammer transients which were coupled to the surrounding water through the diaphragm and were monitored in the near-field by hydrophones. The physical system geometry was varied to include data for a range of pipe sizes from 0.5 in. to 4.0 in. inside dia and from 10 ft to 34 ft in length. The experiments revealed that two distinct major waves could always be identified in each radiated wave pattern. One was found to originate from the primary water hammer compressive wave downstream of the diaphragm. The other major wave was attributed to a precursor wave which originated upstream of the diaphragm. The propagation paths of the two waves are identified and it is shown that their relation to one another in time space is a predictable function of geometry. It is estimated, by extrapolating from the experimental data, that an acoustic pressure in excess of 88 psi at one yard is possible from a system of realistic mechanical design.
Traveling Waves in Rotating Cylindrical Shells
Authors: Srinivasan A. V. , Lauterbach G. F.
Published: November 2010

Vibration analysis of long, thin cylindrical shells rotating about their longitudinal axes is presented. It is shown that only traveling waves may be excited in a rotating shell. Furthermore, coriolis and centrifugal accelerations may have significant effects on the natural wave speeds of forward and backward-traveling waves. Numerical results are presented for a case which includes an external torque acting on the ends of the shell.
An Analysis of Viscoelastic Damping Characteristics of a Simply-Supported Sandwich Beam
Authors: Chatterjee A. , Baumgarten J. R.
Published: November 2010

An energy method is employed to analyze the damping in the fundamental mode of a simply-supported sandwich beam with viscoelastic core material sandwiched between two elastic metallic layers called the facings. The theory developed herein enables one to predict the damped natural frequency and the damping (in terms of logarithmic decrement) of the transverse vibration of a beam of known dimensions, provided the moduli-frequency characteristics of the core material are known. Experimental measurements bear out the accuracy of the theoretical predictions. The theory can very easily be extended for the analysis of higher discrete modes.
Effect of Fillets on Stress Concentrations in Cylindrical Shells With Step Changes in Outside Diameter
Authors: Gwaltney R. C. , Corum J. M. , Greenstreet W. L.
Published: November 2010

The effect of varying the radii of circumferential fillets in the transition region of cylindrical shells with a step change in outside diameter and loaded with internal pressure has been examined by means of finite element analyses for 27 models. Parameters studied were ratios of the thickness of the thicker section to the thickness of the thinner section, ratios of the fillet radius to thickness of the thinner section, and ratios of the inside radius of the cylindrical shell to the thickness of the thinner section. Comparisons are presented between experimental and theoretical results for two experimental models, and duplicate analyses for two cases were made with different computer programs for comparison purposes.
On Elastomer Mount Design When Machine and Foundation Are Multi-Resonant Structures
Authors: Wang Wei-Ming
Published: November 2010

Some considerations on elastomer mount design in vibration isolation when both the machine and foundation have many resonances are presented, and possibilities for improvement on the mount performance are discussed. A lower bound of the effectiveness of a mount in the frequency range embracing these structural resonances is used as a measure of its performance. This lower bound is obtained as a function of the mount parameters as well as the driving-point characteristics of the machine and the foundation. Based on the enhancement of this quantity, a simple and straightforward approach can be formulated to augment the conventional mount design.
Sum and Difference Frequencies in Vibration of High Speed Rotating Machinery
Authors: Ehrich F. F.
Published: November 2010

A vibration incident on a gas turbine engine was noted where two major excitation frequencies were involved—an excitation synchronous with rotor rotation, associated with rotor unbalance, and an asynchronous excitation associated with fluid inadvertently trapped in the rotor. Spectral analysis of the vibration wave form revealed not only the two base excitation frequencies, but also a component at the difference frequency. A mechanism for generating such a difference frequency is hypothesized—the truncation of the basic “beat frequency” wave form by virtue of clearance in the rotor bearing system. Fourier analysis of the hypothesized excitation wave form indicates that components at difference frequency are indeed generated, and also at the sum frequency and a spectrum of higher harmonics and side band frequencies. The hypothesized wave form’s spectral analysis bears a remarkable resemblance to the measured spectrum, except that low frequencies appear to have been greatly amplified in the experimental case, and high frequencies attenuated. This latter fact is attributed to the transmission characteristics of the gas turbine stator system, and is probably responsible for the lack of precise correspondence between the measured and hypothesized wave forms.
Subharmonic Rotor Instability Due to Elastic Asymmetry
Authors: Messal E. E. , Bonthron R. J.
Published: November 2010

Experimental studies were made of the instabilities of the lateral motion of a vertical rotor consisting of an asymmetric shaft having a central disk, a built-in upper bearing support, and an asymmetric set of springs for the lower bearing support. This system is statically indeterminant, and the motion of the disk is described by two coupled Hill equations. Major instabilities were observed when the rotational driving speed was near the maximum or minimum natural frequencies of lateral vibration. Very weak instabilities were observed at one-half of the above frequencies. These subharmonic instabilities are caused by inherent instabilities in the ideal system and also by bearing misalignment. Another very weak instability due to unbalance was observed at one-third of the natural frequencies. The subharmonic instabilities were observed by monitoring the motion of the central mass with two capacitance probes and displaying this motion on an oscilloscope. They were accurately predicted by first and second order perturbation-variation analyses using a method proposed by C. S. Hsu.
Fracture Mechanics and Nondestructive Testing of Brittle Materials
Authors: Clark W. G.
Published: November 2010

The fracture mechanics approach to the development of meaningful nondestructive inspection requirements is presented. The basic concepts underlying the technology are reviewed and the practical engineering aspects of this approach to the prevention of structural failure are demonstrated. Particular emphasis is placed on evaluating the influence of defect morphology (size, shape, orientation, distribution, etc.) on fracture behavior. A hypothetical inspection problem is included and the pertinent considerations associated with the development of a realistic nondestructive inspection specification are discussed in detail.
Large Amplitude Vibrations of Circular Plate on a Uniform Elastic Foundation
Authors: Bolton R.
Published: November 2010

Herrmann’s equations, the dynamic analogues of the von Karman equations, are solved for a circular plate on a linear elastic foundation by assuming a series solution of the separable form involving unknown time functions. The spatial functions include both regular and modified Bessel functions and are chosen to satisfy the linear mode shape distributions of the plate as well as the usual edge conditions. Total differential equations governing the symmetric plate motions are derived using the Galerkin averaging techniques for a spatially uniform load. By extending the concept of normal modes to nonlinear plate vibrations, comparisons between normal mode response and single mode response, as functions of the first mode amplitude, are shown for different values of the elastic foundation parameter. Results are obtained for plates with simply supported and clamped edges and with both radially moveable and immoveable edges. These results are used to discuss the limitations of single-mode response of circular plates, both with and without an elastic foundation.
Theory for the Determination of Flutter Speed of a Class of Hydrofoils
Authors: Mahig J.
Published: November 2010

A theory is given for the determination of the flutter frequency and speed of a hydrofoil traveling at a constant speed. This work used the work of Sears to determine the fluctuating lift and combined it with the chordwise and transverse drag forces to determine flutter speeds. It is shown that flutter speed is sensitive to the drag coefficient as well as lift curve slopes. The theoretical results obtained are shown compared with an experimental study conducted by Huang.
The Resonant Response of a Rectangular Plate With an Elastic Edge Restraint
Authors: Egle D. M.
Published: November 2010

An analysis of a plate, simply supported on three edges and elastically restrained on the fourth, excited by a concentrated load with a harmonic time history, is used to study the peak resonant response of the plate for several configurations and a wide range of edge restraint. Classical thin plate theory is employed with a complex elastic modulus to account for energy dissipation. An approximate method, based on a single term normal mode solution, is developed for calculating the limits of the peak resonant response for arbitrary edge restraint.
Conical Acrylic Windows Under Long-Term Hydrostatic Pressure of 5000 psi
Authors: Stachiw J. D.
Published: November 2010

Conical acrylic windows with included angle 30 deg ≤ α ≤ 150 deg and thickness to minor diameter ratio of 0.375 ≤ t/D ≤ 1.00 have been subjected to 5,000 psi sustained hydrostatic loading of 1,000 hr duration in 65–75 deg F temperature range while the axial displacement of the windows through the flange has been monitored. The magnitude of axial displacement was found to be a function of α, t/D, temperature and duration of loading. Only windows with t/D ratios ≥1.000, 0.625, 0.500, 0.500, and 0.500 for 30, 60, 90, 120, and 150 deg conical angles, respectively, were found to be free of cracks. It is recommended that only windows with included angle α ≥ 60 deg be utilized for general service (long-term and cyclic) under 5,000 psi maximum hydrostatic pressure. The corresponding t/D ratios recommended for general service are 0.750 for α = 60 deg, and 0.625 for α ≥ 90 deg.
On Circular Spot Brakes
Authors: Fazekas G. A.
Published: November 2010

The center of pressure of circular friction pads coincides with the geometrical center of the pads, provided that such pads are constrained to move perpendicularly to the brake disk (as is the practice). Radially, there exists a serious pressure gradient which should be taken into account.
The Filling of the Flash Gap in Closed-Die Forging
Authors: The J. H. L. , Scrutton R. F.
Published: November 2010

The pressures required to drive overflow material into a flash gap of annular shape and ever-decreasing thickness are calculated in the presence of thermal conduction into the die. The behavior of the plastic boundary layer near the die surface is also examined in relation to the transient flow of heat into the die. The energy expended in material acceleration is considered in the analysis and is shown to have a dominant influence on power requirement in some instances.
Nonlinear Seismic Analysis of Thin Reactor Containment Vessels
Authors: Citerley R. L. , Ball R. E.
Published: November 2010

A comparison between the linear and nonlinear seismic analysis of a thin unreinforced steel reactor containment vessel is presented. The effects of the nonlinear coupling between the low Fourier harmonic excitations and the higher Fourier harmonics producing an ovalling response are examined. Imperfection shapes of the containment vessel are employed to provide the mechanism for this response.
Influence of Hold-Time and Temperature on the Low-Cycle Fatigue of Incoloy 800
Authors: Jaske C. E. , Mindlin H. , Perrin J. S.
Published: November 2010

A study has been conducted to determine the low-cycle fatigue behavior of solution-annealed Incoloy 800 bar at temperatures from 800–1400 deg F. The experimental work included evaluation of specimens under both continuous, completely reversed strain cycling and under strain cycling with hold time periods at the strain limits. At 1000, 1200, and 1400 deg F, it was found that 10-min hold-times at the tensile strain limit during every cycle significantly reduced the cyclic fatigue life compared to continuous cycling. However, there was little reduction in cyclic fatigue life when 10-min hold-times were introduced at the compressive strain limits or at both the tensile and compressive limits. The ratio of hold-time cyclic fatigue life to no-hold-time cyclic fatigue life decreased as the length of hold time increased (at constant total strain range) and as the magnitude of strain range decreased (at constant hold-time length).
Optimum Design of Composite Multilayer Shell Structures
Authors: Menkes E. G. , Sandor G. N. , Wang L. R.
Published: November 2010

An improved method of structural optimization is presented which encompasses recent advances in nonlinear mathematical programming methods and methods of analysis for fibrous composite materials. The methodology is based on a transformation of an inequality constrained minimization problem into a sequence of unconstrained minimizations, by applying a penalty function formulation of the Fiacco-McCormick type. Advances include the formulation and solution of a composite shell design problem, including constraints on joint-discontinuity stresses and fibrous composite failure modes. The optimization method is first developed by considering a classic structural design application, the redundant three bar truss. Next, an application to a composite shell structure is demonstrated. Behavior constraints invoked for the shell include consideration of joint discontinuity stresses, shell buckling, deformation limits, and combined stress failure. The objective function is general enough to include both cost and weight criteria. Results for optimum sectional properties for the three bar truss, a composite pyrocarb cylinder and a carbon/aluminum cylinder joined with a composite hemisphere are obtained by this decision making technique.
Analysis of Friction in Ring Compression: A Factorial Experiment
Authors: Mulc A. , Kalpakjian S.
Published: November 2010

The influence of lubricant, rate of deformation, surface roughness, deformation, and temperature on the coefficient of friction of three types of aluminum were studied using ring-compression tests. The experiments were designed according to the factorial plan 24; namely, four variables were investigated at two levels each. The order of importance of these variables were established for each aluminum alloy and at room and elevated temperature.
Optimization of Inertia Welding Process by Response Surface Methodology
Authors: Wang K. K. , Rasmussen G.
Published: November 2010

The inertia welding process was investigated using Response Surface Methodology. The optimum welding condition to yield maximum breaking strength at the weld was attained through a steepest ascent path. A second-order predicting equation for weld strength was established without significant lack of fit to the data. The response surface is represented by a family of ellipsoids. The optimum region covers a relatively wide range of factor levels for welding low-carbon steels. The weld is formed by the subsurface material under severe spiral plastic flow after the surface layer has been disrupted and squeezed out. A successful weld has an average hardness 27 percent higher than that of the base material. The hardness has the highest value at the center and gradually declines toward the edge and away from the interface of the specimen.
Influence of External Loads on Pressure-Carrying Capacity of Outlet Connections
Authors: Palusamy S. , Lind N. C.
Published: November 2010

Six experiments were performed on mild steel models which confirm that the presence of external loads (axial force, coplanar moment, and shearing force) lowers the plastic limit pressure-carrying capacity of outlet connections from spherical pressure vessels. Excellent agreement is observed between experimental results and theoretical predictions obtained from lower-bound rigid plastic analysis. Similar agreement with upper bound analysis is obtained in the case of axisymmetric loading.
Effective Elastic Constants for the Bending of Thin Perforated Plates With Triangular and Square Penetration Patterns
Authors: O’Donnell W. J.
Published: November 2010

Bending tests were run on a series of aluminum beam specimens perforated in triangular and square arrays. Progressively thinner specimens were tested down to 1/8 the thickness covered by the ASME Code. The results for the thick specimens show good agreement with the theoretical generalized plane strain values. The trend of the results with decreasing thickness agrees with the theoretical values for the bending of very thin plates. The applicability of the results is generalized using dimensionless parameters.
A Rotating Valve for High Pressures
Authors: Clement P. H. , Abbot L. H. , Newhall D. H.
Published: November 2010

Some operations of tumbling barrel type mixers require that the vessel be isolated during treatment of the charge. The present paper describes a valve designed and constructed for such a purpose. The valve is attached co-axially to and rotates with the vessel, is capable of containing gas or liquid pressures of 20,000 psi, and is operated by instrument air applied through a slip joint.
Design Charts for the Three-Gear Drive
Authors: Michaud G. H. , Hall A. S.
Published: November 2010

As an intermittent motion mechanism the three-gear drive offers several easily obtained motion characteristics. The design regions in which these characteristics are found are defined by particular input/output velocity and acceleration equations which are presented graphically by a series of design charts.
Calculation of Residual Stresses in Plastic Deformation Processes
Authors: Lee C. H. , Iwasaki H. , Kobayashi S.
Published: November 2010

Three problems, namely, autofrettage process, plastic upsetting of a solid cylinder, and plane-strain and axisymmetric extrusion, are treated for residual stress calculation. A thick-walled cylinder consisting of two loosely fitted concentric cylinders of different materials is subjected to various levels of internal pressure. The residual stresses were calculated with an emphasis on the case where the inner surface of the cylinder yields again upon removal of the internal pressure. Comparison between the calculations and the measurements is given. The residual stresses in plastic upsetting of a solid cylinder were calculated by the finite-element method. An attempt was also made to simulate the real situation in extrusion by the finite-element method. An estimation of the residual stress distribution is then discussed for axisymmetric extrusion problems.
Application of Pseudo-Random Test Signals and Cross Correlation to the Identification of Bulk Handling Plant Dynamic Characteristics
Authors: Roberts A. W. , Charlton W. H.
Published: November 2010

In the determination of the dynamic characteristics of bulk handling systems the complexity of the problem usually makes experimental identification necessary. Experimental techniques which are based on statistical methods are known to be more reliable than conventional methods such as frequency response analysis. A statistical technique that employs a pseudo-random binary coded signal (prbs) to perturbate the system followed by cross correlation analysis may be used very effectively to identify the dynamic characteristics of the system even in the presence of extraneous noise signals. This paper describes this technique and discusses its application to two areas in the bulk handling field; the first deals with the determination of the natural frequencies of screw conveyors used for grain handling and the second deals with the identification of the dynamic characteristics of grain discharge chutes.
The Dynamic State of a Moving Plane
Authors: Eschenbach P. W. , Tesar D.
Published: November 2010

Salient loci existing for special properties of the nth-order motion state are investigated. Generalized analytical expressions are given for the loci as functions of the motion parameters in a rectangular coordinate system. Metric geometry is used to show that the well known Bresse circles are the proper circles to a pencil of circles. Circles similar to the Bresse circles are shown to exist for the nth-order motion state with an associated coaxial pencil of circles. A detailed treatment for special properties of velocity, acceleration, and jerk is presented.
Higher-Order Path Curvature in Spherical Kinematics
Authors: Yang A. T. , Roth B.
Published: November 2010

Characteristic numbers are derived which define a spherical curve, within a stretch rotation, to a given order. The loci of all points, which have the same characteristic numbers, under rigid body spherical motion are studied. These results are useful for synthesis and analysis of spherical linkages. The theory is illustrated by numerical examples for the motion of rolling cones and a spherical turning-block linkage.
Analysis and Design of Cam-Driven Mechanisms With Nonlinearities
Authors: Chen F. Y.
Published: November 2010

The cam-and-follower mechanism is represented by a lumped parameter model of finite degrees of freedom, in which nonlinear system parameters may be taken into account. An approximate dynamic analysis of the system excited by either functional or numerical form of the base motion of a cam is obtained. The method of solution which uses an interpolating polynomial for approximating the excitation function and mechanical quadrature for evaluating the convolution integral is well suited for computer programming. A digital computer program for analysis based on this scheme is developed. In order to utilize the analysis tool for design purposes, parametric studies are conducted, design stratagems are presented and a rational procedure of closed loop computer-aided design is outlined and discussed.
Static Analysis of a Laminated Beam
Authors: DiTaranto R. A.
Published: November 2010

The governing differential equation and natural and rigid boundary conditions have been obtained for a three-layer beam having a middle layer which is primarily shear carrying, using a variational method. Results have been obtained for a fixed-fixed and symply supported beam having a uniform load. For beams having these boundary and loading conditions, curves are presented showing the effect of varying the physical and geometrical properties of the laminated beam on the maximum displacement and stress.
Impact Extrusion—Upper Bound Analysis of the End of the Stroke
Authors: Hahn W. C. , Avitzur B. , Bishop E. D.
Published: November 2010

The upper bound approach is used to analyze the final stage of impact extrusion of a thin or thick-walled cup. The results of two different velocity fields are compared. The prediction and prevention of defects during the final stage is described.