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RESEARCH PAPERS

J. Eng. Ind. 1965;87(4):393-405. doi:10.1115/1.3670852.

A method is presented for the evaluation of the pressure field which is induced in an acoustic fluid by the harmonic axisymmetrical excitation of a submerged thin elastic circular cylindrical shell of finite length. The approach utilizes dynamic influence coefficients from the in vacuo vibrations of the shell and a potential theory source approach for the fluid. Compatibility conditions on the shell-fluid interface allow the determination of the fluid-source strength coefficient and, subsequently, the pressure and/or velocity fields in the fluid. Provision is made for the inclusion of possible viscous-damping effects. Numerical results are presented for several structural configurations.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):406-412. doi:10.1115/1.3670853.

Ends of an initially straight plate strip are rotated 90 deg. Using nonlinear bending theory, the maximum stress is obtained as a function of the half-distance between the rotated ends of the strip. Numerical results are presented in nondimensional form, and the theoretical solution is shown to compare favorably with experimental results. Information given here has a direct application to stress states in a stress corrosion specimen.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):413-418. doi:10.1115/1.3670854.

An analysis is made of the phase change across the interface of a suddenly pressurized, binary liquid-vapor system. The time-dependent temperature and concentration distribution, interfacial growth, and the rate of condensation or evaporation at the interface are obtained. Their application is illustrated by representative numerical calculations for the phase change of one and two-component cryogenic systems of nitrogen-nitrogen, oxygen-nitrogen, and helium-nitrogen.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):419-424. doi:10.1115/1.3670855.

The general algorithm of the discrete maximum principle with information feedback is stated briefly. It is applied to obtain solutions for the optimum stage-weight distribution problems of a multistage rocket vehicle. The first problem treats the structure ratio as a constant in each stage, though it may differ stage by stage. The second problem considers the variations in structural factors with stage weight. The third problem obtains the optimum weight distribution which minimizes hardware weight. Specific examples are solved.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):425-428. doi:10.1115/1.3670856.

Strip-drawing experiments were conducted to evaluate a sigmoidal die profile which, according to slip-line theory, can achieve perfect work efficiency and uniform deformation. The performance of this die profile was compared with that of a straight, a convex circular, and a concave circular die profile, each designed for a similar reduction and axial length. The sigmoidal profile proved best in all criteria examined: Efficiency, uniformity of deformation, and product strength, ductility and fatigue life. The concave circular profile, which is similar to a rolling profile, proved worst in all of these same criteria. The improvement of the sigmoidal profile over the straight profile in fatigue life and ductility was of the order of 20 and 30 percent, respectively, but in efficiency, uniformity of deformation and tensile strength was less than 4 percent. When fabrication of the sigmoidal die is unwarranted by these improvements, the analysis for the sigmoidal profile may yet be useful for approximating the best die angle for a straight profile.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):429-441. doi:10.1115/1.3670857.

An investigation into the dynamics of the metal-cutting process has been carried out using analytical and experimental approaches. An exploratory analysis into the dynamic behavior of the cutting process revealed such dynamic properties as a loop response of the cutting forces caused by the waviness of the work surface. This finding indicates the possibility of unstable behavior of the cutting process in itself. It was possible to describe analytically the phase between the force response and fluctuations of uncut chip thickness for the case of a wavy work surface. Effects of the magnitude of the shear angle as well as of its fluctuations have been studied which make it possible to correlate the instability within the cutting process to the properties of the work material. Apart from the configuration of the cutting process, its physical properties, such as inertia forces in chip formation, have been introduced into the analysis because inertia forces, negligible at steady state, may grow significant if cutting conditions are fluctuating at higher frequencies. An experimental setup has been devised and built featuring a special design of a tool dynamometer particularly suitable for the measurement of dynamic response of the cutting forces. In the setup, a cutting tool activated by a hydraulic shaker is controlled in an average position by a feedback loop mechanism. This setup makes it possible to obtain a record of the dynamic response of cutting forces caused by the fluctuation of uncut chip thickness produced by an oscillating tool in the frequency range up to about 400 cps.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):442-446. doi:10.1115/1.3670858.

Selection of cutter diameter and position of the cutter with reference to the work piece was studied to control the face-milling tool tip failure by fracture. The majority of the tests consisted of studies of the effect of angle of engagement and angle of disengagement on fractures at low and high cutting speeds. The result shows that the angle of disengagement is more critical than the angle of engagement. Favorable cutter diameters and positions based on empirical data are recommended to prevent fractures occurring at low and high cutting speeds. This report suggests that steel can be face-milled with titanium carbide and aluminum oxide tools using optimum setups as suggested by this study.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):447-454. doi:10.1115/1.3670861.

Self-excited chatter, an instability of the cutting process in combination with the machine structure, is a basic performance limitation of a machine tool. A theory is developed which permits calculation of borderlines of stability for a structure having n-degrees of freedom and assuming no dynamics in the cutting process. Harmonic solutions of the system characteristic equation are found using a special chart, and the resulting data are used to plot a stability chart. However, an infinite number of such stability charts exists for a given machine because the structure dynamics vary with cutting-force orientation. This fact makes a simpler index of chatter performance desirable. A simple stability criterion is proposed which states that the directional cutting stiffness must be less than one half the minimum directional dynamic stiffness of the structure for each force orientation to assure chatter-free performance at all spindle speeds. Thus chatter-free performance can be fundamentally identified with adequate structural dynamic stiffness for all cutting-force orientations. Such a broad requirement for dynamic stiffness is difficult to meet in the design stage since structural characteristics are not easily predicted and controlled. Machine testing with continual improvements in the structure to increase dynamic stiffness is currently the best way to combat chatter.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):455-463. doi:10.1115/1.3670862.

This paper is one of four being presented simultaneously on the subject of self-excited machine-tool chatter. Transfer-function theory is applied to obtain a representation of the dynamics of a machine-tool structure. The stability theory developed to investigate self-excited machine-tool chatter requires such a representation. Transfer functions of simple symmetric systems are derived and compared with measurements. When measured frequency-response data of more complex structures are obtained, it provides a very convenient means of data interpretation and enables one to develop the significant equations of motion that define the structure response throughout a specified frequency range. The transfer function presents the phase relationship between structure response and exciting force at all frequencies in the specified range. This knowledge of phase is essential to the proper application of the stability theory and explains the “digging-in” type of instability that is often encountered in machine-tool operation. The instrumentation used throughout these tests is discussed and evaluated. The concept of developing dynamic expressions for machine-tool components and joining these together through properly defined boundary conditions, thereby building up the transfer function of the complete machine-tool structure, is suggested as an area for further study.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):464-470. doi:10.1115/1.3670863.

This is one of four papers presented simultaneously on the general subject of chatter. This work is concerned with finding a representation of the dynamic metal-cutting process which is suitable for use in a linear closed-loop theory of stability of the system composed of the machine tool structure, the cutting process, and their means of combining. Measuring techniques for experimentally determining this behavior are discussed and some problems in the dynamic measurement of forces are explored. It is found that it is not at all sufficient to simply build a dynamometer whose lowest natural frequency is well beyond the range of interest. It is also shown that dynamic cross sensitivity can far exceed static cross sensitivity so that a more general technique for data correction developed in the present work must be used to calibrate dynamic force data. Results obtained to date with an oscillating tool and a flat uncut surface show that some phase, increasing with frequency, is always present between the dynamic cutting forces and the oscillatory uncut chip thickness. This phase is different for the two components of the resultant cutting force. It is felt that two mechanisms, both associated with the tool clearance flank, can explain most of the dynamic cutting effects found in testing.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):471-479. doi:10.1115/1.3670864.

This paper is one of a series of four being presented simultaneously on the subject of self-excited machine-tool chatter. It deals primarily with the applications of the closed-loop chatter theory to several actual machine-tool systems. In all cases the predicted chatter performance is compared with measured data and the correlation discussed. The predicted and measured onset of chatter compare reasonably well, in each example, when the complexities of the test setups are considered. The most serious discrepancy between experiments and the simplified chatter theory is the high-stability region at low cutting speeds. Dynamic specifications to assure the chatter-free performance of a machine tool for a given set of cutting conditions are discussed. The difficulties in arriving at such specifications are also pointed out.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):480-486. doi:10.1115/1.3670865.

The mechanics of orthogonal cutting have been reexamined and for the shear-plane concept of metal cutting, linear and quadratic-force models were suggested. It was shown that for steel SAE-1213, investigated under variable cutting conditions, the dynamic shearing stress remained constant and the linear-force model correlated with those experimental data which were obtained under the absence of a BUE. The angle λ formed by the shear plane and the direction of the resultant force remained constant for each test condition but varied with cutting speed. Neither the Ernst and Merchant minimum energy, nor the Lee and Shaffer solutions are in agreement with experimental observations.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):487-493. doi:10.1115/1.3670866.

The process of hydrostatic extrusion, where the liquid-surrounded billet is pushed through a die by means of liquid pressure instead of a ram, is analyzed. Expressions are provided giving the following: (a) The required pressure as a function of the other process variables. (b) The most suitable cone angle minimizing the required pressure. (c) The capacity of existing equipment. The present study is an extension of a previous study [12] of flow through converging conical dies.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):495-502. doi:10.1115/1.3670869.

The study of rake surface stress distribution was carried out using photoelastic tools. When machining lead, the actual change in stress distribution due to change in tool rake angle from −10 to +20 deg was observed. Certain equations for the magnitudes of maximum and minimum normal stresses at the tool tip were also verified. From the graphs of normal and shear-stress distribution along the contact length, simplified forms of empirical equations for normal and shear force in terms of contact length, rake angle, and so on, were derived. The average friction coefficient was also expressed from the aforesaid studies.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):503-510. doi:10.1115/1.3670870.

This paper contains the annual report of the ASME Survey Committee RR-6. Developments in Railway Mechanical Engineering from September 1, 1963–September 1, 1964, pertaining to cars and locomotives are discussed. A review is given of locomotive development activities, diesel and electric locomotives, passenger freight cars, and transit and suburban cars introduced in North America, Europe, and Asia are described and pictured.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):523-529. doi:10.1115/1.3670872.

The existing theory of propagation of waves of finite amplitude is applied to rubberlike materials using a rigorous finite deformation theory of elasticity. Mooney-Rivlin and Neo-Hookean bodies are investigated in more detail, and explicit solutions are given for the speed of propagation, the particle velocity, and the conditions at the shock front. A numerical example concerning the Neo-Hookean body is given.

Commentary by Dr. Valentin Fuster

DISCUSSIONS

J. Eng. Ind. 1965;87(4):494. doi:10.1115/1.3670867.
FREE TO VIEW
Abstract
Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1965;87(4):494. doi:10.1115/1.3670868.
FREE TO VIEW
Abstract
Topics: Hydrostatics

REVIEW ARTICLES

J. Eng. Ind. 1965;87(4):511-522. doi:10.1115/1.3670871.

Committee of the ASME Materials Processing Field: J. L. Wennberg, Therm, Inc., Chairman ; B. F. von Turkovich, University of Illinois, Metal Cutting Analysis; J. R. Roubik, Kearney & Trecker Corp., Metal Cutting Practice; F. W. Boulger, Battelle Memorial Institute, Plastic Working of Metals; D. A. Farmer, Carnegie Institute of Technology, Grinding; P. A. Smith, Massachusetts Institute of Technology, Metalworking Fluids. The purpose of this review is to appraise the important contributions to the knowledge of material 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 practices throughout industry.

Commentary by Dr. Valentin Fuster

TECHNICAL BRIEFS

J. Eng. Ind. 1965;87(4):530-531. doi:10.1115/1.3670873.

The axisymmetric, transverse vibrations of a spinning membrane disk, centrally clumped between collars with Coulomb friction at the disk-collar interface, are shown, by a scale factor, to be equivalent to those of a membrane fully built into a hub, or clamped between frictionless collars.

Commentary by Dr. Valentin Fuster

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