bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Optimal Control Problem With Variable Terminal Point
Authors: Niemann R. A.
Published: November 2010

The class of optimal control problems is considered in which the terminal point is constrained to lie on some surface in the state space. A computational algorithm is developed which solves the problem for a series of terminal points on the given surface and iterates until the transversality condition is satisfied. An example is considered in which there are several solutions which satisfy the transversality condition, some producing a local minimum of the performance criterion with respect to the variable terminal point and some a local maximum. A sufficient condition for a local minimum is derived.
A Procedure for the Logical Synthesis of Hybrid Control Systems
Authors: Woods R. L. , Reid K. N.
Published: November 2010

This paper discusses a procedure for the synthesis of hybrid control systems which incorporate both continuous (proportional) and decisional (binary) variables. A hybrid logic algebra is presented which permits the mathematical statement of input-output relations involving both types of variables. Simplification of these relations is straightforward using the algebra. An example is presented to illustrate the synthesis procedure. Fluid power, electronic, and fluidic implementation schemes are identified.
The Matched Acoustic Generator
Authors: Toda K. , Roffman G. , Talkin A. I.
Published: November 2010

The design of a swept-frequency, acoustic generator for quickly measuring the insertion power gain and bandwidth of flueric components is described and illustrated. The generator is used to produce and measure the signal incident on flueric components without being affected by reflections from them. The components are connected to the generator by transmission lines. The output of the flueric component is measured in a line of the same diameter as the input line and long enough to attenuate reflections from the far end of the line to negligible levels. The generator produces a 17.7 × 10−3 kilopascal (2.6 × 10−3 psi) acoustic signal in a 1/8 in. (0.32 cm) line over the frequency range of 200 to 5000 Hz. The maximum error in the measurement of the incident pressure signal is approximately 5 percent. More precise construction of the generator could reduce the measurement error, but the accuracy is sufficient for many engineering purposes. The swept-frequency responses and carrier-pulse responses of several flueric amplifiers are illustrated and in particular the frequency response of certain proportional amplifiers has been shown to extend to 4000 Hz.
Dynamic Aspects of Environmental Toxicology
Authors: Spear R. C. , Wei E.
Published: November 2010

The objective of this paper is to show that state variable models and distribution free statistical techniques can be combined to serve as a framework for the collection and synthesis of divergent data in estimating the health impact of different classes of environmental chemicals on human populations. An example is given for the application of these methods to the assessment of the problem of methylmercury in fish.
Time Delay Instabilities in Large Order Systems With Controlled Follower Forces
Authors: Matsumoto G. Y. , Mote C. D.
Published: November 2010

An extension of the τ-decomposition method is used to predict the stability of a continuous system subjected to nonconservative loading. The technique is implemented through Ritz-finite element discretization. The stability of a flexible rocket (or beam) with a controlled orientation thrust vector (or follower force) is examined with respect to finite time delay in the control mechanism. Higher mode instabilities in the rocket are observed in the sample problem and are treated satisfactorily in the technique. Both buckling and flutter conditions are determined from eigenvalue trajectories in the complex plane.
Inverse Problem for Linear Systems Containing Uncertain Parameters
Authors: Panda S. P.
Published: November 2010

The concept of fuzzy dynamic programming and of guaranteed cost control initiated by Chang is applied to the inverse problem of guaranteed cost control for linear systems containing uncertain parameters. Obtained, for a class of linear systems with uncertain parameters, is a frequency-domain criterion which, analogous to that for the deterministic system, is sufficient for the control law to be of guaranteed cost type. The author presents an iterative method which, if convergent, enables one to solve the inverse problem for the general linear systems.
Improvement of Servo Transient Response by Frictional “Negative-Inertia” Mechanism
Authors: Pessen D. W. , Rogozinski J.
Published: November 2010

The negative-inertia mechanism consists of a double-worm drive with a small flywheel attached to the output shaft. By connecting the drive in parallel with the servo load, very high deceleration rates can be obtained. The drive thus effectively cancels most of the load inertia, as long as the load is decelerated. During acceleration, the drive adds slightly to the original load inertia. Characteristic design equations of the system are described, and experimental results presented. The drive is intended mainly for velocity servos, where very high decelerating torques are required without using clutch-brake mechanisms or excessively large servomotors.
A Quantitative Model of Calcium and Phosphate Metabolism
Authors: Reeve E. B. , Joiner K. A.
Published: November 2010

Equations are given which describe elementary features of the absorption, distribution, and excretion of calcium and phosphate in man. Vitamin and hormonal regulation is primarily of calcium absorption from the gut, calcium entry into and loss from bone and renal excretion of calcium and phosphate. Phosphate entry into and release from bone is determined by stoichiometric relations with calcium, while a high and a low extracellular Ca × P “solubility product” determine calcium phosphate precipitation in the extraosseous tissues and failure of bone calcification, respectively. The results of infusion experiments in man are compared with model predictions.
Model-Reference Adaptive Control System Design Technique
Authors: Sutherlin D. W. , Boland J. S.
Published: November 2010

This paper considers the model-reference adaptive control problem which has received considerable attention in the literature in the last few years. An adaptive control scheme is proposed which has terms in the Liapunov function used in the design procedure which are not included in previously proposed schemes. The relationship of this new scheme to existing schemes is shown by considering the root-loci of the linearized error equations between plant and model. Finally, a second order example is given which illustrates the difference between the two previously proposed model-reference adaptive methods and the one proposed in this paper.
Analysis, Design, and Optimization of High Speed Vehicle Suspensions Using State Variable Techniques
Authors: Hedrick J. K. , Billington G. F. , Dreesbach D. A.
Published: November 2010

This article applies state variable techniques to high speed vehicle suspension design. When a reasonably complex suspension model is treated, the greater adaptability of state variable techniques to digital computer application makes it more attractive than the commonly used integral transform method. A vehicle suspension model is developed, state variable techniques are applied, numerical methods are presented, and, finally, an optimization algorithm is chosen to select suspension parameters. A fairly complete bibliography is included in each of these areas. The state variable technique is illustrated in the solution of two suspension optimization problems. First, the vertical plane suspension of a high speed vehicle subject to guideway and aerodynamic inputs will be analyzed. The vehicle model, including primary and secondary suspension systems, and subject to both heave and pitch motions, has thirteen state variables. Second, the horizontal plane suspension of a high speed vehicle subject to guideway and lateral aerodynamic inputs is analyzed. This model also has thirteen state variables. The suspension parameters of both these models are optimized. Numerical results are presented for a representative vehicle, showing time response, mean square values, optimized suspension parameters, system eigenvalues, and acceleration spectral densities.
A Low Sensitivity, Modern Approach to the Longitudinal Control of Automated Transit Vehicles
Authors: Yang S. C. , Garrard W. L.
Published: November 2010

Modern control and estimation techniques are applied to the design of longitudinal controllers for automated transit vehicles. The sensitivity of dynamic response to changes in vehicle parameters and the effects of noisy sensors on control system performance are studied. A method for sensitivity reduction by augmentation of the state vector with the sensitivity vector is proposed and low sensitivity design is developed which provides excellent dynamic response over a wide range of operating conditions and vehicle parameters.
Stability of Car Trailer Systems With Special Regard to Trailer Design
Authors: Collins R. L. , Wong J. P.
Published: November 2010

A linear stability analysis is performed on the articulated vehicle to provide information on the effects that various trailer parameters and variations in tire pressure have on the inherent towing stability of the typical car-trailer combination. Although certain portions of the mathematical model and solution techniques are similar to some previous efforts, the results are generalized to include a much larger class of vehicles than previously presented. The results indicate that hitch loading, trailer length, mass and moment of inertia, and fairly small variations in the car tire pressures can influence trailer towing stability.
New Results in Modeling Heat Exchanger Dynamics
Authors: Gilles Ge´rard
Published: November 2010

A new approach to modeling counterflow heat exchangers is presented which takes into account variations of the heat transfer coefficients with respect to fluid flow rates and temperatures. The approach involves the derivation of a transcendental transfer matrix based on linearization of a set of four nonlinear partial differential equations which describe the heat exchange processes. An approximate rational transfer matrix is derived from the transcendental transfer matrix using a parametrical identification program. The rational model is directly useful in optimal controller design. Results of an experimental study on a pilot heat exchanger are presented to validate the theoretical results.
Automatic Parameter Identification Applied to a Railroad Car Dynamic Draft Gear Model
Authors: Ward E. D. , Leonard R. G.
Published: November 2010

One of the most important components in simulating track-train dynamics is the mathematical model of the connection between two cars, the draft gear-coupler combination. In this paper an automatic parameter identification technique is presented which can be used to generate a nonlinear functional relationship of dynamic draft gear characteristics using experimental data.
Application of Symbolic Manipulation to Time Domain Analysis of Nonlinear Dynamic Systems
Authors: Dubowsky S. , Grant J. L.
Published: November 2010

The digital computer is often used to perform time domain dynamic analyses of non-linear systems. Such analyses are notoriously expensive. In many cases this expense is due to algebraic computation with the solution process. Presented is a solution approach, using modern automatic symbolic manipulation techniques, which will result in substantial computational savings for a wide class of problems. Included are guidelines based on fundamental mathematical analysis, to predict which problems will benefit from this simulation approach.
Train Safety Control System for SHINKANSEN—CPU System With Priority on Safety
Authors: Kataoka Norio
Published: November 2010

For 10 years since its opening SHINKANSEN, Japan’s 210 km/hr railway line, has carried 700 million passengers with a perfect safety record. Train operation safety depends on the working of local devices, while overall traffic control is maintained by a centralized system with a computer to aid the dispatchers. The local devices for safety control have an extremely high failsafe function which rejects any mistaken order from the center, when it judges that said order conflicts with the safety. The present paper describes the fundamental idea behind this highly reliable train operation control system.
Applications and Techniques of Inners to Stability, Analysis, and Synthesis
Authors: Clark M. R.
Published: November 2010

Recently, E. I. Jury has developed an analysis method for linear systems based on the concept of Inners. His approach uniformly treats both continuous and discrete systems while being computationally simpler than previous techniques. The aim of this paper is to introduce and explain some of the more general applications of the Inners method to problems in stability, analysis, and synthesis of linear systems.
Generalized Cumulants Representing a Transient Random Process in a Linear System
Authors: Mayer Arthur
Published: November 2010

The state vector of a linear system responding to gaussian noise satisfies a Langevin equation, and the moment-generating function of the probability distribution of the state vector satisfies a partial differential equation. The logarithm of the moment-generating function is expanded in a power series, whose coefficients are organized into a sequence of symmetric tensors. These are the generalized cumulants of the time-dependent distribution of the state vector. They separately satisfy an infinite sequence of uncoupled ordinary differential tensor equations. The normal modes of each of the generalized cumulants are given by an easy formula. This specifies transient response and proves that all cumulants of a stable system are stable. Also, all cumulants of an unstable system are unstable. As an example, a particular non-gaussian initial distribution is assumed for the state vector of a second-order tracking system, and the transient fourth cumulant is calculated.
Performance Standards in Dynamics
Authors: Komaroff N.
Published: November 2010

A method to evaluate the performance of dynamical systems governed by ordinary differential equations is presented. It is based on averaging functions describing system behaviour (e.g. velocities) over prescribed domains (e.g. surfaces) in phase space. Quantitative measures of motion are introduced to indicate e.g. how oscillatory or how monotone would be the response following a disturbance. Examples demonstrate how these measures serve as new design specifications whose role is to define, compare and control system performance in a more comprehensive manner. Another application of the work is to qualitative studies in both the analysis and synthesis contexts.
Series-Parallel and Parallel Identification Schemes for a Class of Continuous Nonlinear Systems
Authors: Tomizuka Masayoshi
Published: November 2010

This technical brief deals with the identification of a single-input, single-output nonlinear system which is composed of a nonlinear static part and a linear dynamic part. A series-parallel identification algorithm and a parallel identification algorithm are presented; they require the input, output, and the order of the linear dynamic portion of the system. The stability of the algorithms is assured by Popov’s hyperstability theorem. The effectiveness of the identification schemes developed is demonstrated by computer simulation.
Design of a Hardware Observer for Active Machine Tool Control
Authors: Mitchell E. E. , Harrison E.
Published: November 2010

Observer theory is applied to design an active controller for a machine tool such as a lathe to reduce the chatter tendency and forced vibration effects that can be detrimental to a workpiece surface finish. An observer is used to estimate difficult to measure relative motion between the cutting tool and workpiece. The estimated motion is used in conjunction with measured states in a second application of observer theory to design a control system that causes the cutting tool to track the workpiece, negating relative vibratory motion. Hence, the entire control system with the cutting tool position as an output is an observer of workpiece motion. Stability of the controlled system as a function of mismeasurements of dynamical parameters and its ability to reduce forced vibration effects are discussed. Performance calculations are based on a second order machine tool-workpiece dynamical model; however, the presented methods of design and analysis can be extended to higher order systems.
Techniques for Measurement of Winding Tension in Ring Twisting
Authors: Emerson P. D. , Garibian S. K.
Published: November 2010

Direct measurement of threadline tension between a rotating ring traveler and the point of enrollment on the package surface is difficult because of the general inaccessibility of this portion of the threadline. Despite this limitation, at least four methods for deducing yarn tension by measurement of winding moment have been described. A novel, but simple system for measurement of winding tension is here described in which variation in electrical load on a twisting spindle drive motor provides the means for measurement of winding moment.
Design of Heated Cylindrical Pressure Vessels in Transient Creep
Authors: Kraus H. , Siddall W. F. , Lawton C. W.
Published: November 2010

Long, thick cylinders with closed ends undergoing transient creep as a result of a step change in pressure and an axisymmetric temperature history are analyzed. It is assumed that the initial stress state is elastic and that the subsequent redistribution of the stress state is governed by a temperature-dependent, strain-hardening creep law. The results are applicable to a wide variety of both conventional and nuclear power generating equipment, and are illustrated for the temperature histories and geometries that are encountered in the headers of power boilers. A procedure for evaluating the results of such calculations is suggested and illustrated. Results obtained by these procedures indicate that current ASME Boiler and Pressure Vessel Code practices can lead to unconservative predictions of fatigue life if the equipment is to be operated at temperature levels in the creep range.
Design of Aerobic Wastewater Treatment Facilities
Authors: Ford Davis L. , Gloyna Earnest F.
Published: November 2010

This paper is concerned with the various aspects of designing biological treatment facilities capable of removing organic contaminants from industrial wastewaters. Outlined are a sequential approach to developing a conceptual plan, formulating design criteria, and estimating capital and operating costs. Wastewater characterization data, which are a necessary prerequisite for developing basic design concepts, will be considered with respect to the functioning of the treatment processes. This will include the most prevalent organic parameters and some of the pertinent inorganic parameters which are meaningful in terms of plant operation and effluent quality criteria. The necessary bench or pilot scale studies which must precede final design will be discussed. These include the determination of oxygen and mixing requirements, hydraulic retention times in the various unit processes, and sludge-handling requirements. After translation of this information to the sizing of the various basins, mixing and oxygen-transfer equipment and other mechanical appurtenances will be discussed. Some general aspects of estimating the capital costs for these treatment processes will be included. Additionally, many of those expenditures which can be anticipated with respect to maintenance and operation of different types of aerobic plants will be stated.
Computation of Force Traces for the Rolamite
Authors: Cadman R. V.
Published: November 2010

Rolamite geometries having rectangular and diamond cutouts are presented as examples illustrating the use of the geometry analysis computer codes for accurately predicting force traces. The resultant traces are quite different from those predicted by the simple energy analysis, and agree well with experimental results.
Kinematic Analysis of Spatial Mechanisms by Means of Screw Coordinates. Part 2—Analysis of Spatial Mechanisms
Authors: Yuan M. S. C. , Freudenstein F. , Woo L. S.
Published: November 2010

The basic concepts of screw coordinates described in Part I are applied to the numerical kinematic analysis of spatial mechanisms. The techniques are illustrated with reference to the displacement, velocity, and static-force-and-torque analysis of a general, single-degree-of-freedom spatial mechanism: a seven-link mechanism with screw pairs (H)7. By specialization the associated computer program is capable of analyzing many other single-loop spatial mechanisms. Numerical examples illustrate the results.
An Approach to Die Design in Extrusions
Authors: Shabaik A. H. , Negroni F. , Thomsen E. G.
Published: November 2010

The visioplasticity method was used to obtain the complete analysis of stress and strain in axisymmetric extrusions of lead and aluminum at different die angles and friction conditions. The friction losses and effectiveness of the die were determined. A criterion for the selection of the die angle was outlined. A comparison between a sigmoidal and conical die based on the velocity field and friction losses was made.
Traction Limits for Tracked Vehicles Crawling the Sea Bottom
Authors: Nuttall C. J.
Published: November 2010

State-of-the-art methods in regular use for the calculation of the maximum soil-limited net traction of tracked vehicles ashore are briefed. A few simple caveats in applying these to similar vehicles crawling on the sea floor are suggested. Results of limited preliminary tests with a small single-tracked machine in submerged natural silty sand, with supporting in situ soil strength measurements, are presented and commented in context.
Stress Analysis of Thin Elasto-Plastic Shells
Authors: Lomacky Oles , Hyman Barry
Published: November 2010

The stress analysis of thin shells with large deflections loaded into the strain hardening range is presented. Plastic strain incompressibility is assumed. The two governing differential equations in terms of the stress function and the normal displacement are derived in a form where the corresponding equations of the elastic problem are modified only by the addition of the integrals of the plastic strains. The equations can be utilized in conjunction with any yield criterion, flow rule, and hardening law. The theory is applied to the problem of stress concentration around a circular opening in a pressurized spherical shell. A numerical solution is obtained by an iterative procedure using the finite difference technique for the special case of small displacements, bilinear stress strain curve, and deformation theory of plasticity. The speed of convergence for plastic stress and strain concentration factors was found to decrease with increasing pressure.
Mechanical Design Concept for 1000-MVA Superconducting Turboalternator
Authors: Thullen Philip , Smith Joseph L.
Published: November 2010

A design concept for the construction of a 1000-mva superconducting alternator is determined by consideration of (a) electrical requirements, (b) thermal isolation requirements, (c) mechanical strength, and (d) structural rigidity. The alternator consists of a rotating superconducting field winding and stationary water cooled stator. This study indicates that a superconducting machine will have lower specific weight and smaller physical size, higher critical speed, increased efficiency, lower synchronous reactance, increased I22t, and higher terminal voltage than conventional machines.
Relationship Between Plane-Strain Ductility and KIc for Various Steels
Authors: Barsom J. M.
Published: November 2010

In most structural steels, the critical plane-strain stress-intensity factor, KIc, which represents the inherent ability of the material to resist crack propagation, increases with increasing test temperature. In many steels, the rate of increase of KIc with test temperature increases markedly above a temperature region which is designated the fracture-toughness transition region. Because of this transition behavior with temperature and the inherently high fracture toughness of many steels, very thick specimens must be tested to determine valid KIc values. However, the large size of these specimens and the cost of conducting the tests minimize the usefulness of this procedure as a research tool for analyzing the fracture behavior of steels under plane-strain conditions. Therefore, as part of a long-range program to obtain KIc values from small specimens, the relationship between KIc and the ductility measured in a small plane-strain tension test was investigated. The results showed that the temperature transition of the plane-strain tensile ductility at fracture, εf.ps, paralleled that of the KIc, whereas the temperature transition of the axisymmetric ductility (measured in a conventional round tension specimen) was quite different from that of the KIc. At any temperature, the relationship between these properties for steels ranging in yield strength, σy, from 80 to 250 ksi is approximated by the equation KIc=Aσyε2f.ps where A is a constant for a given steel. This relationship indicates that for certain steels the KIc value approaches an upper limit or shelf value with increasing temperature, because as the test temperature increases, the plane-strain tensile ductility approaches an upper limit and the decrease in yield strength becomes negligible. The existence of a KIc shelf would imply that in thick sections the material could fail suddenly, even at elevated temperatures. However, because of the rapid rate of increase of the plastic-zone size with temperature (and thus the through-thickness plastic flow at the crack lip), steels in conventional thicknesses would lose plane-strain constraint at temperatures approaching that for the KIc shelf, and therefore only ductile behavior would be expected at shelf temperatures.
The Optimum Design of Spatial Frames Using the Method of Constrained Steepest Descent With State Equations
Authors: Bartel D. L. , Haug E. J. , Rim Kwan
Published: November 2010

This paper considers the design of a class of spatial frames which occur frequently in mechanical systems: plane frames with out-of-plane loads. The design objective is to minimize the weight subject to constraints on stress and geometry. The method of constrained steepest descent with state equations is introduced to solve the resulting mathematical programming problem. This method differs from the usual methods of nonlinear programming in that the state variables and the state equations are used explicitly in the formulation. This results in a natural matching of the essential features of the design problem and the method used to obtain its solution. The method is effective and general in that it can be readily applied to a wide variety of design problems which occur in mechanical design.
Cause and Prevention of Stress-Relief Cracking in Quenched and Tempered Steel Weldments
Authors: Meitzner C. F.
Published: November 2010

The paper reviews the causes and characteristics of stress-relief cracking, i.e., intergranular cracking in the heat-affected zone that occurs during the exposure of welded assemblies to the elevated temperatures produced by postweld heat treatments or high-temperature service. The findings presented are based largely on work at the Homer Research Laboratories with quenched and tempered steels. Means for preventing cracking during fabrication and service are discussed.
Numerical Determination of the Response of a Linear Vibration System With a Singular Mass Matrix
Authors: Willmert K. D.
Published: November 2010

In numerically determining the response of a linear second-order multidegree-of-freedom vibrational system subjected to a general excitation, the common approach of applying one of the many multistep methods of numerical analysis (e.g., Milne-Simpson, Adams-Bashforth, etc.) leads ultimately to the solution of a system of linear equations. However, when the mass matrix of the original vibrational system is singular, the coefficient matrix of the system of equations also becomes singular and thus the response cannot be determined. Presented is a means of applying these multistep methods to vibrational systems which results in a method that is capable of obtaining the response independent of the singularity of the mass matrix. This technique is particularly useful in optimization where the values of the parameters of the system are unknown in advance, and thus the method of determining the response must be applicable for a wide range of values of the parameters. In the development and investigation of this technique, the causes of the stability problems which develop from the application of multistep methods to systems with nearly singular mass matrices become apparent.
The Autotape/Autocheck System
Authors: Chinitz M. P.
Published: November 2010

This paper is a brief description of the purpose of the system and the principal manual and automatic steps in its operation. Samples of the input data and final artwork of the system are shown. The principal problems encountered in developing and using an automatic drafting machine for this application, and their solutions, will be covered. This includes the necessity for restrictions on line directions on the free-hand sketch used for input, the method of digitizing the sketch, determining an optimum command sequence, and the main sources of error in the final artwork caused by the drafting machine.
Nonlinear Vibration of Buckled Beams
Authors: Min Gwo-Bao , Eisley J. G.
Published: November 2010

The steady state response and stability of free and forced vibration of simply supported, axially restrained, buckled beams is investigated. The equations of motion dealing with the buckled state include the effect of an initial displacement either by initial load or by initial temperature. By an assumed mode solution, the response and stability of two types of vibration are determined—snap-through (symmetrical) and one-sided (unsymmetric) vibration. The theoretical results of the response and stability are verified by analog computer simulation. It is concluded that the stability of the unsymmetric vibration is not a problem and that the different orders of parametric response of the rest modes (the modes originally not excited) in symmetric vibration correspond to the instability regions determined for the approximate single mode response.
Use of Standardized Copper Cylinders for Determining Load and Energy in Forging Equipment
Authors: Altan T. , Nichols D. E.
Published: November 2010

The actual load and energy capacities of equipment must be known for adequately designing the forging process. In the present study, copper samples have been used to (1) determine the maximum production rate, or strokes per minute, of a mechanical press for various levels of forging energy, and (2) calibrate the strain-gage sensors attached on a press frame in order to measure forging loads. For both applications, the accuracy of the measurement technique is acceptable for practical production and engineering purposes.
The Design of a Thin Shell Nuclear Containment Vessel for Seismic Loading
Authors: Hagstrom J.
Published: November 2010

A procedure is presented for the design of a steel nuclear containment vessel subject to seismic loads. A design spectra representation of the loadings is used with a cantilever beam model of the vessel. The results for the beam model are compared with results from two independent shell analyses; a shell modal analysis and a nonlinear shell time history analysis. The beam results are shown to provide a good design correlation.
Effects of Grain Size and Operating Parameters on the Mechanics of Grinding
Authors: Kannappan S. , Malkin S.
Published: November 2010

An investigation is described of the effects of grain size and operating parameters on the mechanics of grinding. Results indicate that the specific cutting energy in grinding, which is the total specific grinding energy minus the specific energy due to sliding between the wear flats and the workpiece, is independent of grain size and decreases with increasing table speed and downfeed. It is postulated that the specific cutting energy consists of chip forming energy which is independent of table speed and downfeed, and plowing energy which decreases with increasing table speed and downfeed. Results for G-ratio, surface finish, and burning conditions are also presented. Of particular interest are the effects of grain size on burning conditions. With finer grain size, burning occurs at larger wear flat area and energy input per unit area ground, but the G-ratio and grinding wheel tool life are less. This is related to increased attritious wear with finer grains.
On the Large Deformation of a Rigid-Plastic Spherical Shell Compressed by a Rigid Plate
Authors: Updike D. P.
Published: November 2010

The behavior of a rigid perfectly plastic spherical shell loaded by means of contact with a flat rigid surface is investigated. The predictions of the analysis are restricted to overall displacements lying between a few thicknesses and about one tenth the shell radius. At each stage of deformation an approximate limit load and corresponding velocity field are found for an assumed deformed shape of the shell, which later is shown to be very close to the calculated deformed shape. A simple formula relating the total axial force on the shell to the displacement of the shell is derived, and its range of validity is investigated. Finally, the results of some static tests of shells are shown to agree favorably with the theory.
An Analysis of Deformation Characteristics and Interfacial Friction Conditions in Simple Upsetting of Rings
Authors: Liu J. Y.
Published: November 2010

Presented in this paper is an analytical investigation of the deformation characteristics at the outer equator and the change in diameter of the inner equator in simple upsetting of flat rings. Material strain hardening is considered inasmuch as the ratio of the friction stress at the tool-workpiece contacts and the material effective stress is assumed to remain constant in the process of deformation. The surface stress components are calculated by means of the Levy–Mises equations, in which the development of anisotropy is disregarded. Numerical comparisons are made with published experimental data.
Stress State Around an Elliptic Hole in a Conical Shell Under Tension
Authors: Chou S. I.
Published: November 2010

Membrane stress state around an elliptic hole in a conical shell under tension is determined by perturbation in terms of a nondimensional cone angle ε and a nondimensional curvature parameter β. Stress state around the hole in terms of the eccentricity of the elliptic hole whose major axis makes an arbitrary angle with the axis of the shell is given. For a crack making an arbitrary angle with the axis of the shell, stress state in the vicinity of the crack tip is given and shows the inverse square root singularity peculiar to crack problems.
Fracture Resistance of Wire-Wrapped Cylinders
Authors: Shoemaker A. K. , Melville T. , Steiner J. E.
Published: November 2010

Steel cylinders wrapped with steel wire have the capability of offering not only an economical high-strength structure, but also a structure with improved fracture resistance compared with that of an unwrapped cylinder of equivalent strength. Accordingly, 2000-psi-pressure hydraulic burst tests were therefore conducted to determine the fracture resistance of 36-in-dia, 60-ksi yield-strength, 1000-psi-pressure wire-wrapped cylinders at different levels of shell notch ductility, which was varied by testing at different temperatures. The cylinders were prestressed with 1/4-in-dia cold-drawn wire, and the shells contained part-through-wall flaws. A similarly flawed unwrapped cylinder was tested for comparison. The working-stress level was 72 percent of the specified minimum yield strength in the shell and 60 percent of the minimum tensile strength in the wire. The results showed that at a pressure double that of the unwrapped shell, no crack extension occurred at a temperature at which the steel exhibited fully ductile shell behavior (+110 deg F). A 2-ft crack extension occurred at a temperature (+10 deg F) at which the steel was still in the transition temperature range from ductile-to-brittle behavior (about 20 percent shear fracture), but a brittle crack (−70 deg F) propagated to the end of the wire-wrapped shell. Except for the brittle propagating crack, wire wrapping appears to provide sufficient constraint of a shell defect or propagating crack to limit bulging and crack-opening displacement. A model based on the compatibility in displacements between the crack opening and the local wire strain is presented for calculating the arrest conditions of the propagating crack in the test at 10 deg F. The same flaw size was critical at the constant failure pressure for all test temperatures, and showed that, as predicted, ductile initiation occurs even at the −70 deg F temperature in both the wrapped and unwrapped-cylinder tests. A circumferential flaw was shown to be less critical than a longitudinal flaw of the same size.
An Improved Technique for Theoretically Determining the Lift Distribution on an Automobile
Authors: Metz L. D.
Published: November 2010

A technique for determining aerodynamic lift characteristics and surface lift distributions of automobiles is derived. Calculations using both this technique, which includes certain second-order effects, and an earlier technique which omits these effects, are compared with actual pressure measurements taken from actual vehicles. The significant improvements possible near certain regions of the vehicle surface are illustrated, and the improved method’s ability to more accurately predict lift and aerodynamic behavior is shown.
The Bougainville 975 TPH Feeder
Authors: Winkler W. A.
Published: November 2010

This paper describes the traveling tripper-surge bin-feeder-screen system as well as the hopper design for mass flow of material. Highlights of the calculations are brought out, particularly those concerned with belt horsepower and pulley stresses due to unusually high tension. A description of mechanical components is included and the selections of steel cable belt and hydraulic drive are discussed.
Review of Materials Processing Literature—1969–1970: 1—Plastic Working of Metals
Authors: Ramalingam S. , Boulger F. W.
Published: November 2010

The purpose of this review is to apprise the important contributions to the knowledge of materials processing appearing in the published literature and to present a digest of this new knowledge through the Society as a contribution to the improvement of materials processing practice throughout industry. The 1969–70 review consists of three parts: Plastic Working of Metals, Grinding, and Materials Processing Literature Published in German Language. A review of Material Removal Analysis and Material Removal Practice will be published at a later date.
Optimization of Drag Minimums Including Effects of Flow Separation
Authors: Addy A. L. , White R. A.
Published: November 2010

Recent work on the supersonic freestream-centered propulsive jet interaction problem has shown that minimum total afterbody drag can be achieved during power on flight with less than a full (zero annular base) boattail. In contrast to optimum power-on configurations, minimum total afterbody pressure drag for power-off (coast) flight requires, in general, a full boattail. Flow separation of the freestream on the boattail is known to occur for a wide range of flight conditions during power-on operation. This flow separation is shown herein to reduce total afterbody drag for nearly full boattails to values which approach the corresponding values for optimized configurations without separation. Thus, the possibility of reconciling flight-profile drag minimums for both power-on and power-off conditions by using afterbody separation is suggested and shown to be a feasible design consideration.
Dwell Motion From Spatial Linkages
Authors: Shrivastava A. K. , Hunt K. H.
Published: November 2010

The potential of single-loop spatial linkages to produce an output dwell from a rotating input is broadly surveyed. Then three comparatively simple four-bar linkage arrangements are selected, and studied in detail. The dwell characteristics of all three are viewed via surface-surface or surface-curve “matching” at a spherical pair. Attention is mainly confined to symmetric output-input motions, and the accuracy of dwell is assessed.
A Transmission Index for Spatial Mechanisms
Authors: Sutherland G. , Roth B.
Published: November 2010

A general index of the quality of motion transmission for spatial mechanisms is developed using the theory of screws. This index is shown to be related to the mechanical error possible in a linkage. A method for synthesizing spatial linkages with desirable motion transmission and mechanical error characteristics is developed and examples are shown for the RGGR linkage.
Constraint Coordination for the Single Motion State
Authors: Eschenbach P. W. , Tesar D.
Published: November 2010

The methods of constraint coordination are derived and applied to an industrial problem to synthesize a mechanism solution. The motion of an input constraint of unknown proportions is coordinated with the motion of a planar body to yield constraint dimensions. The motion of a secondary constraint is chosen to optimize the transmission angle over a cycle of motion.
An Analysis of Control Methods for Galloping Systems
Authors: Clendening W. R. , Dubey R. N.
Published: November 2010

It is shown that the motion of a galloping system can be quenched by using (a) linear, tuned, damped vibration absorbers, (b) aerodynamic in-span dampers, or (c) spring-damper support systems. It is also shown that either (a) mechanical dampers mounted near the endpoints of the system or (b) tension operated dampers can be used to control galloping provided the self-excitation terms have a small magnitude.
Characterization of Abrasive Tools by Continuous Time Series
Authors: Pandit S. M. , Wu S. M.
Published: November 2010

A succinct characterization of abrasive tools using continuous time series is developed. It is based on three parameters: natural frequency ωn, damping factor ζ, and variance γ0. These parameters can be readily interpreted in terms of the visual records. The interpretation, along with the effects of the physical constituents on the parameters, is discussed and illustrated for profiles of 8 grinding wheels, with different grit size, hardness, and structure.
Deviation Forces From the Wedge Penetration Failure of Anisotropic Rock
Authors: Bradley W. B.
Published: November 2010

Deviation of boreholes is caused by drill string flexibility and the interaction between the drill bit and the formation being drilled. While work has been devoted to the analysis of drill string mechanics, less work has been directed toward the understanding of bit rock interaction. This paper presents the results from some experimental work on the deviation forces and chip volumes generated by the wedge penetration of anisotropic rock. The single blow wedge penetration tests were conducted on blocks of Green River shale cut to simulate formation dip angles from 0 to 90 deg. During the tests, the time history of the force required to penetrate the rock, together with the deviation forces perpendicular and parallel to the strike of the formation were recorded. Tests were conducted using wedges with 30 and 60 deg included wedge angles at atmospheric and 10,000 psi confining pressures. In conjunction with these tests, triaxial tests were performed to determine the failure characteristics of this particular rock. Results from these tests showed that appreciable deviation forces were generated by the 30 and the 60 deg wedges at both confining pressures. Maximum deviation forces were generated in the 30 deg dip region and in the 60 deg dip region, with the deviation forces tending to zero at 0 deg, 90 deg, and in the region of 45 deg. The results are in general agreement with field observations. The volumes generated correlate with the measured forces as well as field experience. Predominant chip volumes were created on the updip side of the tooth at low dip angles and on the downdip side of the tooth at high dip angles for both tooth geometries. Published predictions on the advantages of 60 deg teeth for deviation control were found to be in disagreement with experimental results. When combined with the measured rock failure properties, the theoretical work upon which the above predictions were based did predict deviation forces in qualitative agreement with the experimentally determined values.
Effect of Draw-In on Formability in Axisymmetrical Sheet Metal Forming
Authors: Lee P. K. , Choi C. Y. , Hsu T. C.
Published: November 2010

In the formability of sheet metal, distinction is made between the formability at the critical section, the formability of the material, and process efficiency. It is shown that draw-in has an adverse effect on the formability at the critical section, but greatly improves the gross process efficiency, which measures the extent to which the formability of the material is exploited in a particular process. The effect of draw-in on the strain distribution in the workpiece is shown in a triangular coordinate system for strains.
The Modeling and Optimum Design of Real Spatial Frames Including the Evaluation of Competing Design Concepts
Authors: Bartel D. L. , Swann D. C.
Published: November 2010

Optimization methods are used to evaluate competing design concepts for real spatial frames. The modeling of spatial frames to obtain an accurate, inexpensive analysis capability is described in detail. The resulting optimization/analysis method is applied to evaluate two design concepts for front end loader lift arm assemblies.
Hyperbaric Chamber Lighting
Authors: Canty J. M.
Published: November 2010

Internal electrical systems have been the cause of some very serious accidents in hyperbaric chambers. This paper describes a new “light pipe” system which can be installed in a very small opening in the vessel wall. Most of the IR energy is intercepted before the light enters the chamber resulting in a cool light source, simple to install and maintain. A description of the system is presented along with performance for several light pipe configurations.
On Predicting the Dynamic Effects of Clearances in One-Dimensional Closed Loop Systems
Authors: Dubowsky S.
Published: November 2010

The dynamic response of a complex one-dimensional system with clearances is considered. It is shown that the presence of the clearances results in a substantial amplification of the internal dynamic forces of the system. This behavior is compared with the characteristics of a simple general model of the clearance coupling called an impact pair. It is shown that the impact pair is capable of predicting the effects of clearances on the dynamics of one-dimensional systems and represents a valuable design tool.
Analysis of Nonlinear Transient Motion of a Geared Torsional
Authors: Wang S. M.
Published: November 2010

The dynamic torsional analysis of gear train systems has implemented many practical system designs. A computer analysis to predict the steady-state torsional response of a gear train system is presented in reference [1]. The current paper extends this work to the linear and nonlinear transient analysis of complex torsional gear train systems. Factors considered in the formulation are time-varying gear tooth stiffness, gear web rigidity, gear tooth backlash, shafts of nonuniform cross section, linear and nonlinear damping elements, multishock loadings, and complex-geared branched systems. For linear systems, the equations of transient motion are derived and closed-form solutions can be obtained by the state transition method [2]. For nonlinear systems, numerical methods are also presented. The method may be used as a means to analyze gear train start/stop operational problems, as well as constant speed response subject to internal and external disturbances.