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RESEARCH PAPERS

J. Eng. Ind. 1972;94(4):961-964. doi:10.1115/1.3428346.

Under impact, when the velocity is reduced from its initial value vo to zero over a very short period of time, the deceleration a and its rate of increase ȧ (the principal parameters determining the survival of the occupants) are dictated by the length x of the vehicle deformation and by its dynamic process. The model equation suggested by the author is a = Ktn with 0 < n < 1. The constants K and n depend on the design of the vehicle and on deformation conditions. Alternative mathematical expressions of safety deformation requirements are considered with a view to improved design in the future and to speed restrictions on designs currently in use. Analysis of the formula reveals the conflict between the requirements for low a and ȧ, as well as the problem of high initial ȧ. An acceptable compromise can be recommended. Using suitable n values, a more satisfactory dynamic process can be achieved and the time of deformation tt can be increased considerably at a given length xt . The optimal value for n seems to be around 1/4 . The concepts of deformation coefficient and deformation factor are included in the discussion.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):965-970. doi:10.1115/1.3428347.

An exploratory drill point stress analysis was obtained experimentally using a three-dimensional photoelastic technique. A drill model was stress-frozen under simulated drilling conditions and seven segments were sliced perpendicular to and along the cutting edge for subsequent photoelastic analysis. Isochromatic fringe patterns from slices close to the drill periphery suggest an action analogous to orthogonal cutting. Generally, stresses become more compressive as the cutting edge or the outer corner is approached. A maximum shear stress was found to exist along the cutting edge at a point about three-fourths of the distance from the chisel edge and was noted to be similar to a previously determined cutting edge temperature distribution.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):971-978. doi:10.1115/1.3428348.

An analytical solution for the symmetrical lateral extrusion process based on slip line theory is presented. The analysis incorporates the stress equations modified for strain-hardening and the conventional First Theorem by Hencky. Material flow, material strength, and forces for extruding 6061-0 aluminum are thus analyzed. The calculated ram forces are found to be in substantial agreement with experimental results.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):979-984. doi:10.1115/1.3428349.

It is shown that the tool life of tungsten-carbide tools can be increased by at least 80 percent by treating the surface of carbide tools with various oxides. Among the oxides that increase the tool life are titanium dioxide, zirconium oxide, aluminum oxide, and chromium sesquioxide. The oxide treatment was done by diffusing the oxide layer, which had been coated on the tool surface, into the subsurface layer in a vacuum of 10−5 torr at various temperatures. The increase in tool life is greater at higher temperatures of the oxide treatment, the maximum temperature being the sintering temperature of the carbide tools. It is believed that the decrease in the tool wear rate is caused by the retardation of mass diffusion between the tool and work, lowering of the chip-tool interfacial friction, and by decrease in the temperature at the chip-tool interface. Other possible causes are also discussed.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):985-990. doi:10.1115/1.3428350.

This paper deals with a challenge to apply the method of indicial response analysis for obtaining the frequency characteristics of total cutting system, tool system, and cutting zone. The feasibility of this method has been verified by simulation tests. Furthermore, linearity in cutting zone has been demonstrated to a first approximation by utilizing the proposed method. As examples of its application, on-line prediction or prevention of chatter vibration and simple evaluation of machine tool structure have been proposed.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):991-998. doi:10.1115/1.3428351.

The power and forces required to fill a corner cavity in closed-die forging depend on the amount of transient thermal conduction from the heated billet into the cold die. The amount of this conduction is calculated numerically for a steel billet and a steel die, by neglecting the flow of heat in the direction parallel to the movement of metal. The theory takes account of variations in the flow stress consequent on temperature change within the bulk of the plastic material and in the plastic boundary layer near the interface.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):999-1006. doi:10.1115/1.3428352.

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.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1007-1019. doi:10.1115/1.3428281.

Noise control problems exist where high pressure, high temperature gasses are vented to the atmosphere. An example is used to illustrate an approach to the design of an acoustically treated expansion chamber for a typical noise problem caused by superheated steam vented to the atmosphere. An analysis is developed to aid in the design of the acoustically treated expansion chamber type muffler for broadband frequency application. The algorithm as well as the supporting theory are sufficiently general so as to be applicable to a number of high velocity gas-generated noise conditions. An Appendix of terminology definitions is included.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1020-1024. doi:10.1115/1.3428282.

A short-time dynamic acceptance test for machine tools based on a single measurement of a coefficient of dynamic stiffness (Kd ) is proposed. A feature of this test is that it takes into account the random fluctuation of the cutting forces that will be experienced by the machine tool in actual operation. Kd is defined as the inverse of the standard deviation of the steady state translational dynamic response of the machine tool under these cutting forces and is a function of the static stiffness of the machine-tool-workpiece system, the damping in the machine, and the equivalent intensity coefficient of the random cutting forces. The analytical expression for the coefficient Kd is obtained from the stationary solution of the Fokker-Planck equation that describes the probabilistic response of the machine tool. The form of excitation considered in the final results is the equivalent “white-noise” spectral density of the ensemble of the cutting forces experienced by the particular machine over the range of feed rates and cutting speeds during operations such as roughing, finishing, etc.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1025-1034. doi:10.1115/1.3428283.

A computerized modular method is developed for predicting shape complexity, material volume, load, stress distributions, and center of loading in forgings. The method consists of dividing a forging into standard components which can be assembled in a building-block manner to analyze a given forging. The method has been applied to a nonsymmetric rib-and-web-type aircraft part from 6061 aluminum. The flow stress during forging, in two distinct zones of the part, was calculated by estimating average forging temperatures. The predicted values of the forging variables are compared with experimental results. The predicted forging load, which varies with the tool-material interface friction, agreed well with the measured load for a friction factor of about 0.3.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1035-1043. doi:10.1115/1.3428286.

The detailed deformation characteristics involved in axisymmetric plastic indentation was examined. Circular punches with flat and hemispherical ends were indented into specimens prepared from SAE 1215 steels under as-received and annealed conditions. The load-displacement curves were recorded, and measurements were made of the geometrical changes of the workpieces and of the strain distributions for various punch-workpiece dimensions. Furthermore, the mode of deformation was examined by revealing the flow lines, and fracturing of the workpiece was also observed.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1045-1052. doi:10.1115/1.3428289.

Assuming plane shear surfaces and chip tool friction force in the direction of the relative displacement between chip and tool, the direction of chip flow is determined. The condition of minimum energy determines the shear angle. The cutting ratio, the cross section of the chip, and the cutting forces are theoretically predicted. The solution for the case of cutting in a solid prismatic block whose free surface is parallel to the direction of cutting is worked out.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1053-1059. doi:10.1115/1.3428292.

Over 150 conical frustum acrylic plastic windows were subjected to 10,000 psi hydrostatic loading of up to 1000-hr duration in deep ocean simulators maintained at 65–75 deg F ambient temperature. Axial displacements of the windows under hydrostatic loading through the conical cavity in the flange were recorded and plotted as a function of time, thickness to minor diameter ratio (t/D), and included conical angle α. Data indicate that only windows with α ≥ 90 deg and t/D ≥ 0.75 are satisfactory for sustained long-term hydrostatic loading of 1000-hr duration at 10,000 psi in ambient temperatures ≤80 deg F. For general service, which includes also cyclic pressurizations to 10,000 psi, an included angle α ≥ 90 deg and t/D ratio of ≥ 1.0 are recommended. The axial displacement of windows recommended for 10,000 psi service is approximately 0.04D after 1000 hr of sustained loading. Approximately 75 percent of this displacement takes place during the first hour of pressure application.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1060-1066. doi:10.1115/1.3428295.

The dynamic similarity of two geometrically similar extrusion processes was examined. The flow lines, values of the flow function ψ, and velocity components were compared for the hot extrusion of SAE 1018 steel at 1800 deg F and 10 ips, and the superplastic eutectic alloy of lead–tin at room temperature and 0.088 ipm. The comparison showed a good agreement between the two cases and that dynamic similarity of the flow fields was achieved under the previous conditions. Material properties were examined and results indicated that similarity of the mechanical properties is necessary for the dynamic similarity of the flow fields.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1067-1071. doi:10.1115/1.3428296.

Service loads of machine-tool dynamometers are usually reduced to a system of three mutually orthogonal force components through a fixed reference point. Three additional components (moments) result if the resultant cutting force does not pass through the reference point. At least some of these six components reach finite values under machining operations; sometimes all six must be considered. It follows that the response surface of the output signal of each channel to all six components must be known in order to evaluate the measurement process. Six component calibration of multi-component dynamometers, such as, e.g., wind tunnel balances, is known to be a rather expensive and time-consuming operation. It will be shown that, under some rather general limiting conditions, useful estimates of the response surface parameters may be obtained with a reasonable number of straightforward tests. Expensive special purpose calibration stands are dispensed with, simple jigs and general purpose equipment being all that is needed for most applications. The performance of machine-tool dynamometers may, therefore, be analyzed in detail, and a good understanding of their measurement capabilities may be obtained, even when operating under a light budget. Details are given concerning the application of the proposed method to a tool-post-type lathe dynamometer.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1073-1076. doi:10.1115/1.3428299.

Of the numerous methods developed to predict failure of isotropic materials exposed to a three-dimensional state of stress, experimental studies tend to confirm the validity of the distortional energy theory. To date no rational basis of predicting inelastic action in an orthotropic material exposed to principle stresses coincident with the material axes has been proposed. This study assumes that distortion energy may be used to predict failure of orthotropic materials, and a usable algebraic method of predicting failure is developed.

Topics: Failure , Stress
Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1079-1086. doi:10.1115/1.3428305.

The upper bound approach is used to analyze the early stage of impact extrusion of a thin or thick-walled cup. It is shown that during the early stage of extrusion with a flat ram the ram pressure increases linearly with increasing penetration of the ram, increased area of contact between the tool and the workpiece, and poorer lubrication. With the same friction and process geometry the early stage of extrusion is made easier by using a nosed ram instead of a flat one. The optimum nose contour can be determined by a minimization technique.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1087-1093. doi:10.1115/1.3428308.

Stylus type instruments that employ needle tracers for examination of surfaces by means of translating the stylus over the surface and recording the undulations which occur during that traverse are analyzed by means of scanning electron microscopy. The scanning electron microscope (SEM) has superior resolution capabilities and can directly record the interactions of stylus with surface. The true levels of resolution of this instrument are measured and discussed in terms of finite size of the stylus, damage produced in the specimens due to stylus plowing, and stylus skipping and nonparallel tracking. The fundamental difference between magnification and resolution is examined in terms of tracer devices. Needle or stylus tracer devices are found to be dynamic microhardness testors which produce outputs which must be carefully judged as to their meaning and reliability in terms of faithfully recording the topographical nature of surfaces. The potential future of the SEM as a true nondestructive surface quality inspection tool is emphasized.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1094-1098. doi:10.1115/1.3428309.
Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1099-1107. doi:10.1115/1.3428310.

An analytical method applying a chance-constrained programming concept is proposed to determine the optimum cutting conditions considering the probabilistic nature of the objective function and constraints. The proposed analytical method is illustrated through an application to an example. It is shown that the optimum cutting conditions are significantly affected by the probabilistic nature of coefficients in the constraints. The effect of the uncertainty of the predicted tool life in the production cost function on the optimum cutting conditions is also considered. The study further investigates the effects of the cost-time parameter and allowable maximum force on the optimum conditions and the resulting production cost.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1108-1111. doi:10.1115/1.3428311.

Velocity fields of tube extrusion problems through curved dies are presented for an incompressible material. These velocity fields are also applicable to conical and square-cornered dies. Thus, in principle, upper bound solutions for tube extrusion problems through arbitrarily shaped dies are obtained. As an illustration, tube extrusion processes through conical dies of small cone angle have been treated. Effect of die geometry and friction is presented graphically.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1113-1123. doi:10.1115/1.3428313.

The paper describes measurements of lateral flow of material which took place during cold rolling thin strip. This sideways flow is shown to have a considerable influence of the final flatness of the strip. A mathematical model of a rolling mill stand is described, which includes a calculation allowing for sideways flow of material. Parameter studies are made using the mathematical model, which show the influence of crowns, tensions, back-up and work roll bending on the resultant strip shape. A comparison is made between results predicted by the model and test results obtained on a production mill.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1124-1129. doi:10.1115/1.3428316.

A model for free oblique continuous cutting is proposed. In addition to the hypotheses used in Merchant’s model for free oblique continuous cutting, coincidence of chip-tool friction force with the direction of chip flow on the tool face is assumed; moreover, the deformation process in the primary deformation zone is considered as a case of plane strain. The direction of chip flow is predicted and is found to be function of the cutting conditions. The theoretical predictions compare favorably—less than 10 percent discrepancies—with experimental data published in literature for conditions of low friction at chip tool interface.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1131-1141. doi:10.1115/1.3428319.

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.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1142-1148. doi:10.1115/1.3428320.

There is little data available in the literature regarding temperature gradients and heat transfer in diving chambers (decompression chambers) with an environment of normal diving mixtures of helium and oxygen at pressures up to 33 atm. This paper reports on a preliminary study that was made to determine the actual behavior of the gas mix-tures in a model chamber as compared to predicted behavior. It was hypothesized that three distinct regions of flow are developed from the circulation of the environmental gas. Equations were developed for the temperature profiles and checked by the model data. Agreement between theory and test data was quite good. The test procedure and instrumentation are described in part. Full details and data are available in reference [18].

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1149-1155. doi:10.1115/1.3428321.

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.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1157-1163. doi:10.1115/1.3428324.

A prototype drill grinder was designed and built based on a computer aided drill point geometry analysis. The new grinder controls all essential drill point grinding parameters. The new grinder was evaluated by grinding drills, measuring their point geometry parameters, and comparing these measurements with their expected values. The effects of five parameters, consisting of three grinding and two cutting condition parameters, on the drill thrust and torque are determined by an experiment using a two-level factorial design.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1164-1170. doi:10.1115/1.3428325.

Three suggested phases of improvement in the design methods for gray iron components are: (a) design based on accurate strength and deformation analyses, instead of the currently used elastic formulas; (b) an ultimate strength instead of working stress approach to ensure consistent strength designs; and (c) factors of safety based on probabilistic methods to help eliminate bias based on the behavior of the material. An initial contribution covering these three aspects is presented.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1171-1177. doi:10.1115/1.3428328.

The S3 semisubmerged ship concept consists basically of two parallel torpedo-like hulls, submerged to a depth of about two diameters and attached to an above-water platform by means of four vertical struts. Horizontal fins and control surfaces attached to the hulls provide dynamic stability and permit full automatic control over pitch, heave, and roll. The anticipated advantages of the S3 over conventional ships are greatly improved seaworthiness, high-speed potential, large internal volume and deck area, controllability, and many aspects of its unusual hydrodynamic form. The S3 concept appears to be most applicable to small ships (100 to 15,000 tons) having missions associated with the use of sonar—the handling of aircraft, weapons, or submersibles—and for missions requiring a high degree of seaworthiness and stability.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1179-1187. doi:10.1115/1.3428330.

Two correlations are developed (for which there is precedent in the literature) interrelating the many process variables for adequate design of a flash stage. Both correlations are based on the Colburn factor, jm, for mass transfer. These correlations were determined from experimental data obtained from American Machine and Foundry Co. (AMF) in Connecticut and another model by Baldwin-Lima Hamilton (BLH) in Wrightsville Beach, North Carolina.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1189-1192. doi:10.1115/1.3428333.

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.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1193-1205. doi:10.1115/1.3428335.

Kineto-elastodynamics is the study of the motion of mechanisms consisting of elements which may deflect due to external loads or internal body forces. This paper describes the initial phases in the development of a general method of kineto-elastodynamic analysis and synthesis based on the flexibility approach of structural analysis, which may be applied to any planar or spatial mechanism. Dynamic error is investigated due to flexural, longitudinal, and torsional element strain, and system inertia fluctuations; the treatment of Coulomb and viscous friction is indicated. Kineto-Elastodynamic Stretch Rotation Operators are derived which will rotate and stretch both planar and spatial link vectors reflecting rigid body motion plus elastic deformations of the link. A numerical example is presented to demonstrate the elastodynamic analysis technique.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1206-1213. doi:10.1115/1.3428338.

The workpiece temperature in cylindrical plunge grinding is considered as a superposition of a base temperature and an interference zone temperature. A solution for the transient base temperature distribution is derived. A two-part experiment for determining thermal effects is described. The heat transfer coefficient at the workpiece surface is measured in the first part, and specific grinding energy and workpiece temperature are measured in the second part. The energy entering the workpiece during grinding is determined from the base temperature solution and experimental data. Results obtained with several grinding fluids and application systems are presented. The energy entering the workpiece was found to be 75 to 85 percent of the total grinding energy during dry grinding and 25 to 35 percent during wet grinding.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1215-1224. doi:10.1115/1.3428342.

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

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1972;94(4):1225-1230. doi:10.1115/1.3428343.

A procedure for smoothing the experimental values of the flow function ψ in axisymmetric extrusion through curved boundaries was developed. The analysis was applied to a 45 deg conical die with a 6:1 extrusion ratio and a circular arc of 0.33-in. radius and 0.033-in. land at the exit section. An analytical expression of ψ in terms of r and z was obtained and used in the calculation of velocity and strain rate components in axisymmetric extrusion of a superplastic of the eutectic of lead–tin. The stress components were obtained from the known values of the strain rates by considering equilibrium and plasticity equations and material properties.

Commentary by Dr. Valentin Fuster

DISCUSSIONS

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