bluuebunny/crossref_metadata_2025 huggingface dataset:
The Deformation Process in Metal-Cutting
Authors: McDonald W. J. , Murphey B. F.
Published: December 2011

An analysis of the orthogonal chip process for a strain-hardening material is presented together with a qualitative evaluation of the effects of temperature increases and of flank rubbing. An expression is derived for the average stress on planes through the tool point ahead of the shear plane. The authors postulate that the strain-hardening requires that a stress-reinforcing phenomenon be present and that this requires the shear to take place in a region of increasing stress. The rate of increase required is postulated to depend on the final strain imparted to the chip. Data from the literature are presented to support this view. The conclusion is drawn that the strain imparted to the chip is a measure of the deviation of the shear angle from the Merchant minimum-energy condition.
Supersonic-Wind-Tunnel Air-Drying-System Design
Authors: Macios T. W.
Published: December 2011

Air-drying system design for supersonic wind tunnels entails many complexities. These complexities are discussed in this paper with the express intention of establishing criteria for air-drying-system design. Various types of systems are examined and a method of drying-system selection is presented.
Tensile and Short-Time Creep Properties of N-155 Alloy Sheet
Authors: Bernett Eugene C.
Published: December 2011

The special test equipment and procedures developed for the evaluation of ultrashort-time elevated-temperature mechanical properties of materials are described herein. The tensile and high-stress creep data obtained for Haynes N-155 alloy sheet are reported. At rapid strain rates, the high-temperature tensile strengths were up to 300 per cent higher than those obtained at conventional testing speeds. At high temperatures and high stress levels, however, creep rates were shown to be extremely rapid, and in most cases, the creep strength became a critical factor. The application of rapid-strain-rate tensile data and high-stress creep data in short-life designs is discussed.
A Critical Comparison of Metal-Cutting Theories With New Experimental Data
Authors: Kobayashi S. , Herzog R. P. , Eggleston D. M. , Thomsen E. G.
Published: December 2011

The following alloys were investigated in orthogonal metal-cutting tests at varying cutting speeds, rake angles, and feeds: Steel SAE 1112 annealed and as-received; steel SAE 1020 as-received; steel SAE 4135, annealed, as-received, and Rockwell hardnesses 27 and 35–37; aluminum alloy 2024-T4; aluminum alloy 6061 in the 0 and T6 conditions; alpha brass. The new data obtained in the present investigation under wide variation of test conditions (speed for SAE 1112 annealed and as-received was varied from 0.083–1010 fpm) confirmed earlier observations [1, 3] that the shearing stresses are independent of the test conditions investigated. These observations were supported by theoretical considerations. Correlation of metal-cutting data with compression data on the basis of the incremental or distortion-energy theory was good for the ductile metals. Less perfect correlation was observed with SAE steel 4135 and aluminum alloy 2024-T4. It was found further that none of the known theoretical angle relationships were in agreement with all of the experimental data.
Structural Weight Approximation for a Bell-Nozzle Divergent Section
Authors: Brewer G. D. , Levin E.
Published: December 2011

In the preliminary design of missile systems it is necessary to consider the weight of the individual components which comprise the missile. The usual procedure in weight approximation is to consider that an article is composed of small regular-shaped bits, each of whose weights is easily found and whose sum approximates the weight of the total article. When the component is such an irregular shape that a simple approximation cannot be made, or where the number of digital operations is excessive, the estimation of its weight becomes a tedious procedure. In this report, a method is derived for approximating the structural weight of such an article, namely, the divergent section of a bell-shaped nozzle for a rocket motor.
Optimum Tolerances of Sheet Materials for Flight Vehicles
Authors: Hoffman George A.
Published: December 2011

A method is derived for specifying economically optimum tolerances for a variety of sheet materials for use in flight vehicles. The results indicate a significant disparity between present industry practices and the apparent optimum tolerances. These tolerances are listed as possible target requirements for rolling programs of new and future metals.
Deformation and Moments in Elastically Restrained Circular Plates Under Arbitrary Load or Linear Thermal Gradient
Authors: Zaid M. , Forray M.
Published: December 2011

The problem of a circular plate, with a central hole, elastically constrained against rotation and deflection, acted upon by a transverse linear temperature gradient or a general axisymmetrical loading condition is considered in this paper. With the aid of presented graphs and simple algebraic equations, it is a relatively simple matter to construct the desired deflection and stress pattern for any combination of elastic constraints and load distribution.
Analysis of Buckling Column Spring With Pivoted Ends and Uniform Rectangular Cross Section
Authors: Blake Alexander
Published: December 2011

Design formulas and working charts are derived for predicting load-deflection characteristics and maximum bending stresses in initially straight buckling column springs, of uniform cross section, considered to be pin jointed at the supports. Load-deflection analysis is based on the study of a slender bar, compressed beyond critical buckling, made by Lagrange. Stresses are calculated using the elementary strength of materials theory. The predicted load-deflection curves for typical spring proportions are compared with the experimental results.
On the Analysis of Random Errors in Precision Grinding Operations
Authors: Hahn Robert S.
Published: December 2011

The concept of random variables as used in the theory of probability is applied to machining operations, in which the input stock, hardness, stock distributions, etc., vary. Output errors are calculated in terms of input variations and machining time, specifically for grinding operations. In particular, output size errors are related to input stock variations as well as variations of wheel sharpness. Variations in runout or ecccentricity are related to the initial runout and stock. A dimensionless variable for comparing metal-cutting machine tools is also introduced which permits an estimate of elastically produced errors. Transient forces on grinding wheels are also considered.
Machinability of Nodular Cast Irons: Part I—Tool Forces and Flank Adhesion
Authors: Ham I. , Hitomi K. , Thuering G. L.
Published: December 2011

Three grades of nodular cast iron (60, 80, and 100) were tested to determine the cutting and feed forces required to machine the materials, to determine the performance of several grades of carbide and oxide cutting tools, and to investigate the flank adhesion phenomenon. Cutting characteristics for grade 80 and grade 100 were found to be the same as for high-strength gray cast irons with similar Bhn values. Flank adhesion, with accompanying sharp increases in cutting force values, was encountered only when grade 60 was machined with carbide tools. An attempt was made to correlate tool composition and flank adhesion.
An Experimental Investigation of the Electrolytic Grinding Process
Authors: Cole Reno R.
Published: December 2011

Data are presented covering the effect of several variables on grinding rate for the electrolytic grinding process. The relative amount of material removal due to electrolysis and due to conventional grinding action was investigated. The Faraday current efficiency of the electrolytic part of the process was found to be near 100 per cent to the extremely high current density of 700 amps per sq in. This is thought to result from the scraping action of the wheel abrasive which prevents passivation of the work anode. Several phenomena of the process are explained on the basis of hydrogen gas pressure in the work-wheel interface. A formula is presented for calculating the hydrogen gas pressure. Equations are proposed for the basic chemical reactions of the process.
Practices in Operational Management—Engineering Management
Authors: Paules C. E.
Published: December 2011

Inherent in the history of the engineering profession has been constant advance in its methods of carrying out its tasks and ever-improving quality of its work output. In this country, it has played a major role in aiding in the development of the United States into its leading industrial position. Seldom in our history has the engineer been confronted with a challenge—to think and to perform—equalling that of the past decade.
A Tabular Collocation Method for Beam Vibration
Authors: Chicurel R. , Suppiger E.
Published: December 2011

This paper presents a procedure, based on the integral equation method, for the calculation of the natural frequencies of lateral vibration of beams with variable cross section. The approximate solution is obtained by collocation [1, 2]. A preliminary step in the analysis is the determination of static deflection curves; this is carried out in a convenient tabular form. An example of a stepped beam is given and the results are compared to those obtained by Myklestad’s method [3].
Stress and Strain in Spinning Paraboloid Dishes—2
Authors: Cohen M. J.
Published: December 2011

Solutions for the stress and strain systems in spinning paraboloid dishes, both holed and whole, are presented. They are applicable to all such dishes of aperture small enough to justify the usual approximation for small angles of cos θ ≈ 1, sin θ ≈ 0. The direct stress p, the hoop stress f, the shear stress s, the bending moments Mθ and Mφ, and the radial displacement Δ are obtained as power series in θ, the angular distance of any point of the dish at the center of the sphere of curvature at the dish apex. These series in θ are expressed in terms of tabulated coefficients which are essentially functions of a single basic dish parameter Rα2/h. The range for Rα2/h covered is 0 ≤ Rα2/h ≤ 10.
The Flexural Vibrations of Thin Laminated Cylinders
Authors: White J. C.
Published: December 2011

A method is developed for calculating the natural frequencies of vibration of a thin right circular cylinder. The vibration pattern may contain any number of peripheral or axial nodes. The cylinder is assumed to consist of a large number of thin laminations of two dissimilar materials, arranged alternately, and with the plane of a lamination normal to the axis of the cylinder. Built-in and simply supported end conditions are considered.
Damping Structural Resonances Using Viscoelastic Shear-Damping Mechanisms: Part I—Design Configurations
Authors: Ruzicka Jerome E.
Published: December 2011

This paper considers the problem of resonant vibration control in designing structures to function in modern dynamic environments. Methods of specifying structural damping are given and damping properties of engineering materials are reviewed. The disadvantages of some current design practices are outlined and special structural designs which incorporate viscoelastic shear-damping mechanisms are suggested as a method of controlling the resonant flexural vibrations of structures. The general dynamic characteristics and design philosophy of structures and strip dampers (additive damping techniques) that incorporate viscoelastic shear-damping mechanisms are discussed. A description is given of some parameters useful in the design of viscoelastic-damped structures.
Magnetic Properties of Malleable Irons
Authors: Bock W. K. , Hutchinson T. D.
Published: December 2011

Standard or ferritic malleable iron is satisfactory for use as a cast, soft magnetic material. It is made by heat-treating white iron. In addition to its magnetic properties, it can be readily cast into intricate shapes and is one of the most machinable ferrous metals. By merely changing the heat-treatment, pearlitic or martensitic malleable iron can be produced from the same white iron. Like all soft, magnetic materials, ferritic malleable iron is mechanically soft. On the other hand, pearlitic malleable and martensitic malleable irons are graphitic steels and exhibit a range of hardness and strength. They have the same availability as ferritic malleable and much of its machinability. Ordinarily, carbon steels are not used for magnetic applications, but because the pearlitic and martensitic malleables have the advantages outlined above, there is some idea that they might be used as a compromise by giving up some magnetic quality to gain mechanical properties. This paper supplies the magnetic properties necessary for such compromise. Magnetically, pearlitic and martensitic malleables behave like steels if allowance is made for the graphite which is present.
Free Oscillations of Edge-Connected Simply Supported Plate Systems
Authors: Ungar Eric E.
Published: December 2011

A simple semigraphical method for calculating the natural frequencies of two-plate systems is developed, a two-plate system being one made up of two rectangular plates simply supported at all edges and joined at a common edge. Charts for easy determination of the afore-mentioned natural frequencies are developed. One of these gives, as a by-product, the natural frequencies of rectangular plates (of any dimensions) having one edge clamped, the remaining three simply supported. It is demonstrated that the higher natural frequencies of two-plate systems are very nearly equal to those of the individual component plates. Equations for the mode shapes are also given.
Deflection of Heat Exchanger Flanged Joints as Affected by Barreling and Warping
Authors: Dudley W. M.
Published: December 2011

The conventional formulas for bolted-flange design, given in the ASME Unfired Pressure Vessel Code, provide for stresses due to initial bolt tightening and the axial force of internal pressure. Additional forces tending to loosen a joint are created by unequal radial expansion or barreling of the flange and shell, due to temperature differences or pressure, and by unequally warped flanges. Formulas have been developed for the extra bolt loads required to overcome these effects and applied to a heat-exchanger joint in a catalytic reforming unit. The margin of safety against leakage is increased by using soft gaskets that can re-expand after being compressed, and by retightening bolts after operating temperatures and pressures are reached. Joints designed to resist initial bolting and hydrostatic forces only are likely to leak because of barreling effects or warped flanges.
Thermal-Stress Analysis of Irregular Shapes
Authors: Bijlaard P. P. , Dohrmann R. J.
Published: December 2011

A method has been developed for determining the thermal stresses resulting from an axially symmetric temperature distribution in an irregularly shaped cylindrical vessel. It permits the calculation of the principal stresses, rotations, and displacements for all points within the cross section and on the boundary of the geometry being considered. Finite-difference techniques are used to solve the governing fourth-order differential equation that must be satisfied. The method was applied to geometries and temperature distributions for which classical analytical solutions are available, and the agreement was very good. An example is given for which the “isostress” and isothermal lines are plotted for an irregular geometry with varying temperature gradients in the radial and longitudinal directions.
An Experimental Investigation of Temperature Distribution at Tool-Flank Surface
Authors: Chao B. T. , Li H. L. , Trigger K. J.
Published: December 2011

The measurement of temperature distribution at the flank surface of a cutting tool is characterized by the extremely small extent of the surface over which the temperature field is explored. This paper describes a technique which makes use of a moving lead-sulfide, photoconductive, infrared radiation detector. The surface in question is quickly scanned by the detector’s view field. For the level of temperature encountered, data are reproducible and the method may be used to determine temperature distribution over sliding contacts in general. From the measured flank surface temperatures, tool-chip interface temperature distribution was deduced using geometrical, electric analog. The technique also has the general application in finding steady temperatures at locations which are not accessible for direct measurement. The computed tool-chip-interface temperature profile agrees well with known crater-wear patterns. Tool-face frictional force calculated from thermal considerations compares favorably with independent dynamometer measurement.
Some Controlled Metal-Cutting Studies With Resulfurized Steels
Authors: Thomsen E. G. , Kobayashi S. , Shaw M. C.
Published: December 2011

Cutting tests, including controlled tool-chip contact area and controlled artificial flank wear-land studies, were made with five resulfurized steels having nearly identical strength properties. It was found that the dynamic shear stress was 62,700 psi and appeared to be identical for all steels at the two cutting speeds of 356 and 936 fpm with sulfur contents of the alloys ranging from 0.11 to 0.37 per cent. For the low sulfur steel (S = 0.033 per cent), the dynamic shear stress was found to be 72,000 psi. A comparison of the effective stresses obtained from compression tests with those from metal cutting tests showed good correlation at equal strains. The controlled tool-chip contact area and the controlled wear-land studies at feeds of approximately 0.005 ipr and cutting speeds of 318 to 356 fpm appear to indicate that sublayer plastic flow at the tool chip and tool work interfaces was essentially absent.
Performances of Carbide Tools in Machining 18-8 Stainless Steel
Authors: Takeyama H.
Published: December 2011

The austenitic 18-8 stainless steel is one of the most troublesome materials to be machined because of the tendencies of work-hardening, high temperature, and adhesion. The ultimate object of the experiment is to establish the machining standard of the austenitic stainless steel with carbide tools based upon tool life. Generally speaking, tool life in a modern machining practice should be specified not only by the flank wear, but by the crater. This paper describes the process of obtaining the optimum cutting conditions for turning the stainless steel from the viewpoint of tool life, and discusses how the tool life is governed by flank wear and crater depending upon the cutting conditions.
Milling Forces Measured With a Planetary-Gear Torquemeter
Authors: Roubik J. R.
Published: December 2011

Cutting-force data, obtained with a torquemeter of planetary-gear design in carbide milling tests on SAE-1018 cold-rolled steel at feeds from 0.002 to 0.030 in. per tooth, cutting speeds from 87 to 957 fpm, and depths of cut from 0.100 to 0.300 in. with a tool geometry of −7°, 0°, 3°, 5°, 0°, 15°, 1/64″ × 45°, are presented. The influences of variations in cutting speed, feed per tooth, and depth of cut on tangential cutting force are depicted graphically. Cutting-force values for other workpiece materials are also included. With these data a comparative method of experimentally verifying the computed high efficiency of the torquemeter itself is derived and applied. A method of obtaining highly accurate determinations of milling machine efficiency under actual oscillatory cutting loads is described with an example. Actual and theoretical traces of the variation of tangential cutting force with both single and multiple-toothed face milling cutters are illustrated for comparison.
On Determining the Hardness of Grinding Wheels—I
Authors: Colwell L. V. , Lane R. O. , Soderlund K. N.
Published: December 2011

A new method for evaluating the hardness of grinding wheels has been developed. It involves crushing small amounts of abrasive from the surface of a grinding wheel while in rolling contact with a hard steel wheel. Measured reaction forces provide a sensitive indication of significant variations in the hardness as well as other important properties of bonded abrasives. A laboratory analysis of the method demonstrates that the hardness values incorporate the same elastic constants which have been shown to be important in actual grinding. The analysis shows also that it is feasible to establish a universally applicable industrial standard for grinding wheel hardness. The method is valuable also as a research tool and may be expected to aid in producing more uniform abrasive products and to yield information which will help improve practices in the manufacturing plant.
Synthesis of Rectilinear Motion by Mechanical Harmonic Function Generators
Authors: Shaffer Bernard W. , Krause Irvin
Published: December 2011

A general method is presented for generating controlled rectilinear motion to any desired accuracy. The required motion is expressed in terms of a Fourier series whose coefficients are shown to be related to the governing dimensions of a plane mechanism. The mechanism may be designed to generate enough terms of the Fourier series to satisfy any desired accuracy. The technique is then used for a particular problem to illustrate its application and the method by which the error of approximation may be evaluated.
Thermal Stresses in Spherical Case-Bonded Propellant Grains
Authors: Krause Irvin , Shaffer Bernard W.
Published: December 2011

Expressions are derived for the bond stresses induced by a radially symmetric temperature distribution in spherical propellant grains bonded to spherical casings. Equations for the evaluation of radial and tangential stresses in the propellant and its casing have also been derived. Both solid and hollow propellant grains have been investigated. Design considerations have been developed to enable the designer to minimize the bond stress. A comparison between the hollow and solid spherical propellant assembly shows that the hollow sphere has a lower bond stress than the solid sphere, assuming all other factors are the same.
An Axial-Flow Porous Plug Apparatus
Authors: King R. C. , Potter J. H.
Published: December 2011

The design of an apparatus for determination of Joule-Thomson coefficients is presented. An axial flow porous plug is utilized and the downstream flow is so arranged that one concentric flow path serves as a heat shield for the other. This guard-ring principle, together with virtual elimination of radiation and convection heat transfer, reduces the heat leakage that has been associated with previous axial-flow designs. A prototype was constructed and tested with gaseous nitrogen. The Joule-Thomson coefficients obtained agree, in the range 2-20 atmosphere and 50-150 C, within one per cent with published values.
Thermal Design for Microminiaturized Circuitry
Authors: Kammerer H. C.
Published: December 2011

Now that a number of techniques exist which permit the fabrication of circuits with a theoretical packing density of 1 million or more circuits per cubic foot, thermal design is an essential initial consideration. In most cases the drive toward microminiaturization is based on the need for a large number of circuits in a small weight and volume. If present circuit designs are taken as the basis for microminiaturization, it can be shown that with most materials being considered the temperature will rapidly rise to the point where circuits will become inoperative. This paper outlines some of the basic considerations in terms of heat conductivity of materials, maximum safe working temperatures, and circuit power levels as dictated by current devices. A method is described whereby a proposed design configuration can be computer-analyzed in terms of isothermal lines and maximum hot spot temperatures and decisions made on that basis as to which type of cooling is most appropriate.
Application of Four-Pole Parameters to Torsional Vibration Problems
Authors: Molloy C. T.
Published: December 2011

This paper deals with the application of the method of four-pole parameters to torsional vibrations. Results are developed from fundamental principles. The four-pole parameters for the basic rotational elements are derived. These include shafts (both lumped and distributed-parameter cases), disks, dampers, and gears. The equations which must be obeyed, when these elements are connected, are presented. The application to construction of equivalent electrical circuits is given and in particular a method for constructing the equivalent circuit of distributed-parameter systems is put forth. The torsional analogs of Thevenin’s and Norton’s theorems are given for rotational sources. The fundamentals mentioned above are then applied to the following problems: (a) The effect of substituting one four-pole for another in a torsional system. (b) The effect of opening a four-pole system and inserting a new four-pole between the separated four-poles. (c) Calculation of all the torques and angular velocities in a tandem system. (d) Calculation of natural frequencies of undamped four-pole systems.
Catalytic Filtration of Ozone in Airborne Application
Authors: Boberg John E. , Levine Myron
Published: December 2011

Studies were undertaken to determine a practical method of reducing the ozone content of cabin intake air typical of high-altitude, high-speed aircraft. To make use of the aircraft ram air temperature rise, catalytic filters were investigated for purposes of ozone destruction. The effective temperature range and life of the more promising catalytic materials were investigated. A brief study of ozone adsorptive materials at lower temperatures is included.
Strain Rate Distribution During Experimental Metal Rolling
Authors: Yajnik K. S. , Frisch J.
Published: December 2011

Plastic deformation in commercially pure lead strips during torque-free rolling was investigated. The experimentally determined slip-line field was compared with the theoretical solution of a similar problem and was found to be different, having a plastic-rigid boundary with inflection points at the entrance section. It was observed that plastic deformation occurred well ahead of the initial contact point between the strip boundaries and the roll surfaces.
Free Machining Steel—IV: Tools With Reduced Contact Length
Authors: Usui E. , Shaw M. C.
Published: December 2011

Tools which provide controlled contact on the tool face are used to study the action of free machining steels. The mean normal stress on the tool face σc is found to increase with increased undeformed chip thickness (t = feed) or with a reduction in the controlled length of tool face contact. An increase in σc in turn is found to promote the stability of the built-up edge to higher speeds. The high-speed finish produced with a cut-away tool is thus found to be inferior to that produced with a conventional tool. Manganese sulfide is found to have a similar effect on surface finish, but lead tends to improve the finish obtained at a high cutting speed. The cut-away tool provides improved low-speed finish in all cases as does the addition of either manganese sulfide or lead to the steel. Manganese sulfide is found to become more effective with increased undeformed chip thickness t, while lead behaves in the opposite manner. This observation along with several others is in agreement with the idea that manganese sulfide is a poor solid “lubricant,” while lead is an effective solid lubricant. An optimum chip-tool contact length appears to exist at which the tool life will be a maximum at any combination of cutting speed and feed. From this it follows that an optimum combination of sulfur or lead content, degree of cold work, cooling capacity of cutting fluid, or extent of tool-face limitation exists, since all of these quantities influence the resultant length of contact between chip and tool.
Strain Hardening in the Yielded Compound Cylinder
Authors: Becker S. J. , Kraus H.
Published: December 2011

The theory of a previous paper which was designed for nonhardening plastic deformation of simple and compound cylinders in axisymmetric generalized plane strain is extended to include linear strain hardening in the plastic range. The method, which is limited to small strains, uses a modified Tresca yield condition and assumes incompressibility for both the plastic and the elastic ranges.
Influence of Normal Stress on Creep in Tension and Compression of Polyethylene and Rigid Polyvinyl Chloride Copolymer
Authors: O’Connor D. G. , Findley W. N.
Published: December 2011

New apparatus suitable for compression creep tests of slender specimens is described. The apparatus is designed to prevent buckling and to introduce a minimum of friction. Results are reported for tension and compression creep of polyethylene and annealed, unplasticized polyvinyl chloride copolymer at 75 deg F and 50 per cent relative humidity. The stress σ, strain ε, time t data from these tests were found to be describable with reasonable accuracy by the equation ε=ε0′sinhσ/σε+m′tnsinhσ/σm where ε0′, m′, n, σε, and σm are material constants. The results for polyethylene show that the creep in tension and compression were virtually the same. However, the creep in tension was similar but larger than in compression for polyvinyl chloride. These observations are interpreted in terms of the material structure and the influence of the normal stress on active shear planes.
Machinability of Nodular Cast Irons: Part II—Effect of Cutting Conditions on Flank Adhesion
Authors: Hitomi K. , Thuering G. L.
Published: December 2011

To determine the effects of cutting conditions on flank adhesion, nodular cast iron grade 60 was machined dry and wet with carbide cutting tools K6, cast iron cutting grade, and K4H, steel cutting grade. Decreasing the feed rate raised the critical cutting speed at which flank build-up occurred and lowered the resultant tool force. For tools with positive rake angle, the critical cutting speed was generally higher and tool forces were lower than for tools with negative rake angle. A clearance angle of 15 deg eliminated flank adhesion, as did the use of cutting fluids. Flank build-up was analyzed chemically and metallurgically. Methods to prevent flank adhesion are recommended.
Runout Path of an Airplane Equipped With Skids
Authors: Ip Ching-U
Published: December 2011

Equations of motion of the airplane subject to the influence of cross wind, rudder steering, and drag chute, during runout, are developed which would be valid even when the direction-of-travel angle and the yaw angle are large. A procedure of synthesizing the runout path step by step explicitly is presented. A flight vehicle capable of orbiting around the earth usually does not have ground steering capability because its weight has to be held to a minimum. This study will enable a designer to determine whether or not the vehicle will have inherent stability to land on a runway.
Load-Deflection Behavior of Conical Spiral Compression Springs
Authors: Wang Han-Chung , Worley Will J.
Published: December 2011

The geometry of both the Archimedean and the logarithmic spiral, when formed into the third dimension, is considered. Changes in profile resulting from the choice of constant helix angle and from constant spacing between adjacent coils along the axis of the conic are presented. The axial and lateral load-deflection behavior of conical spiral springs is considered in terms of the above variables. Strain-energy methods are used to obtain the load-deflection relationships. Nonlinear effects due to compression of the large diameter coils are discussed.
Analytical Determination of Poles in the Coincidence Position of Links in Four-Bar Mechanisms Required for Valves Correctly Apportioning Three Fluids in a Chemical Apparatus
Authors: de Jonge A. E. Richard
Published: December 2011

In an important chemical apparatus, admission of three fluids had to be made in quantities required by the correct reaction cycle. For the control of the fluid admission valves, four-bar linkages were to be used. The dimensions of the linkages were determined from the reaction curves and the valve opening curves by means of a digital computer. It was found that, during the cycle, the links of the two driven linkages used came into a coincidence position each, in which their motions were indeterminate. They were made determinate by auxiliary pin tooth and mating gap mechanisms added to the respective links at the polodes in these coincidence positions. This required finding a new and simple kinematic-algebraic solution for determining the poles in the general case of a four-bar linkage in these coincidence positions. A new geometrical solution is added. An outline for the practical design is presented. In an Appendix, the formulas derived were tested by application to cases for which the poles are known or can be found easily.
Feasibility of Pressure Hulls for Ultradeep Running Submarines
Authors: Wenk Edward
Published: December 2011

Whether the next generation of submarines can operate more deeply depends on the feasibility of developing pressure hull structures sufficiently strong to resist intense external pressure, but also sufficiently light that adequate excess of buoyancy remains over hull weight to accommodate propulsion plant, personnel, and “payload.” By extrapolation of principles of design now employed for shallower running boats, calculations were made of the strength-weight characteristics of structure in the depth range of 2,000 to 20,000 feet. Results indicate that, by utilizing materials such as aluminum alloy 7079-T6, titanium, fiberglas-reinforced-plastic, and superstrength steels, submarine hulls appear feasible for successful operation to depths of one, two, and even three miles, without trade-off sacrifices in speed or combat potency. The yield strength-density ratio of a material serves as its index of efficiency, but cost and ease of fabrication must also be considered in design. Significant problems remain in construction technology that could be mitigated by use of sheathed assemblies wherein nonweldable materials can be effectively employed as hull constituents.
The Upper-Bound Solution as Applied to Three-Dimensional Extrusion and Piercing Problems
Authors: Yang C. T.
Published: December 2011

The upper-bound solution for plane-strain problems is modified and applied to three-dimensional extrusion and piercing. Johnson’s graphical solution is used to solve axisymmetric, eccentric, and two-bar extrusion problems of a lead billet. Kudo’s unit-deforming region approach is employed to solve cylindrical piercing problems of six nonferrous metals. The analytical extrusion pressure is compared with Frisch and Thomsen’s experimental data. A reasonably close agreement is obtained in the first two cases. The calculated piercing pressure is compared with the experimental results of Fukui, et al. A remarkably good agreement is observed for all six cases. Therefore the upper-bound solution after slight modification can be extended to three-dimensional problems in extrusion and piercing. A general conclusion for extending the upper-bound approach to all forming operations cannot be drawn until further study is done along this line.
Self-Induced Vibrations in Metal Cutting
Authors: Albrecht Paul
Published: December 2011

Solution of the problem of dynamic stability for the machine tool-cutting process system depends primarily on the assessment of behavior of the cutting process under dynamic conditions. It has been found that under dynamic conditions, apart from force fluctuations due to variations in cutting conditions, additional force fluctuations take place as a result of cyclic variations of the shear angle in the cutting process. Difference in force response of a cutting process to the static dynamic variations of the cutting conditions has been explained by the presence of cyclic variations of shear angle under dynamic conditions. Peaks of the force wave, resulting from dynamic variation of the cutting conditions, are known to be displaced with respect to the originating wave. This displacement has been thought to be due to a time lag of the whole force response; however a sound physical basis for this point of view has not previously been found. The present investigation provides a physical basis for such observations, showing that the displacement of force peaks is caused by the skewing of the force wave by the presence of asymmetric force pulses due to cyclic variations of shear angle. The same event—the cyclic variation of the shear angle—has been recognized to be a sign of instability of the cutting process in itself, resulting in a cyclic chip formation process. Instability of the cutting process in itself has been found to depend mainly on the cutting conditions and not on the dynamic properties of the cutting system. Analytical expressions derived for the frequency and amplitude of cyclic chip formation have been found to be in a good agreement with the results of measurements of these quantities. Study of the effects of dynamic events in metal cutting upon tool life has revealed propagation of fatigue cracks on the wear land. The propagation of the cracks has been found to be in good correlation with the presence of force pulses due to the cyclic chip formation. The way in which the foregoing event affects the tool life has been reconstructed, allowing selection of those conditions which improve tool life.
Grinding With Abrasive Disks: Part 1—Test Procedures and Performance Criteria
Authors: Mohun W. A.
Published: December 2011

Equipment and procedures for test grinding abrasive disks and for coating such disks in the laboratory are described. Criteria useful in evaluating performance are defined and discussed. Discard criteria for worn disks are analyzed and the suggestion made that the effective life of the disk ends when the cutting rate is some specified percentage of its initial cutting rate. This paper is the first of a series dealing with the mechanism of the cutting action of abrasive disks.
Grinding With Abrasive Disks: Part 2—Disk Performance and Dressing Mechanisms
Authors: Mohun W. A.
Published: December 2011

Performance data for 24-grit aluminum oxide disks on mild steel and on stainless steel are presented. The dressing mechanisms are shown to be different on mild steel and on stainless steel since the whole grit is the cutting tool on mild steel while micropoints are the cutting tools on stainless steel. It is shown that the total weight of metal removed during the life of the disk depends primarily on how long the dressing mechanism continues to function, and that erect grain orientation favors dressing on mild steel but is not a factor in dressing on stainless steel.
Grinding With Abrasive Disks: Part 3—Attritious Camber, Glazing, and Rate of Cut
Authors: Mohun W. A.
Published: December 2011

It is shown that the worn surface of a grit has a camber which causes decreasing depth of cut, leading to glazing. Orthogonal cutting theory is modified accordingly and equations are developed for rate of cut and for total metal removed. It is shown that erect grain orientation favors high rate of cut on mild steel but is not a major factor in rate of cut on stainless steel. It is predicted that decreasing the number of active grits will improve disk performance up to the point where dressing becomes excessive.
Maintenance and Support of Hydraulic Thrust Vector Control Systems for Long-Term Unattended Storage
Authors: Fruktow Nicholas N. , Gatzek Leo E.
Published: December 2011

Second-generation ballistic missiles are being developed for compatibility with the concept of long-term storage in permanent underground housing, with missiles in firing position, and in a condition of full operational readiness. It is intended that operational status be maintainable without major interruption over a three-year storage period. This report investigates the various factors which are considered to significantly influence the capability of hydraulic thrust vector control systems to remain in a state of operational readiness when subjected to such periods of inert storage as components of total missile configurations. The following sections present a detailed outline of technical difficulties which may be encountered, information and data resulting from applicable test programs, and the general nature of solutions to apparent problems. The design concept of a storable hydraulic thrust control system is considered to be feasible, but may be effectively achieved only by fulfillment of certain stringent design requirements and by further development of preservation techniques to preclude the need for in-field maintenance.
Development of an Extended Duration 1200 Deg F Torque Motor
Authors: Farron J. R.
Published: December 2011

The application of high performance fluid power servos for attitude and engine control functions to advanced flight vehicles necessitates advancing the state-of-the-art of hydraulic systems in regard to their sensitivity to environmental conditions. In order to achieve this objective, the Air Force has sponsored the design and development of a 1000 deg F hydraulic system. This paper reviews the development and evaluation of an extended duration 1200 deg F torque motor representing the first component developed specifically for this system. Emphasis in the paper is placed on the approach to material selection, motor design, and the test results obtained.
Combination of Solutions of the Torsion Problem by Means of a Connection Function
Authors: Carter William J.
Published: December 2011

A method is presented whereby known solutions to the torsion problem may be combined to form new solutions provided that the bar cross section can be broken down into sections for which the solution of the torsion problem is already known. It is shown that the correction function required is one which satisfies the Laplace equation for the combined cross section.
Analysis of Two-Dimensional Motion Resisted by Coulomb Friction
Authors: Goodman T. P.
Published: December 2011

The effect of Coulomb (dry) friction between surfaces of adjacent machine members, either in preventing relative sliding motion or in absorbing energy when relative motion does occur, has traditionally been analyzed on a one-dimensional basis. The two-dimensional analysis presented in this paper shows how the effectiveness of Coulomb friction in preventing relative sliding motion is greatly reduced by eccentric loading, and how the effectiveness of Coulomb friction in absorbing the energy of an oscillation may be greatly reduced by the addition of a second oscillatory or unidirectional motion. The results of the analysis are correlated with experimental data.
Instability in Conventional Spinning of Cones
Authors: Kobayashi S.
Published: December 2011

The condition of flange wrinkling in conventional spinning of cones is established by modifying the theory of instability in deep-drawing of cups. Experiments conducted in order to test the theoretical results show that agreement exists between theory and experiments.
Analysis of Wire Drawing and Extrusion Through Conical Dies of Small Cone Angle
Authors: Avitzur Betzalel
Published: December 2011

Analytical expressions are derived for the required front pull for wire drawing, as well as the back push for extrusion. The effect of each of the process variables on these forces is presented graphically. The process variables are: the cone’s semiangle (α) initial (Ri) and final (Rf) wire radius, material yield limit (σ0) at uniaxial load, back pull (σxb) and front pull (σxf), coefficient of friction (μ) or shear factor (m), die land (L), exit velocity (vf), and entrance velocity (vi). The power balance is set for these powers: (1) Internal power of deformation of the wire, (2) power involved with the back force on the wire, (3) power involved with the front force on the wire, (4) power losses due to friction between the wire and the die.
Process Kinetics as Design Criteria for Bio-Oxidation of Petrochemical Wastes
Authors: Busch A. W.
Published: December 2011

Biological oxidation is widely used in industrial waste treatment. In order to achieve economic design, a thorough understanding of the process and its kinetics is necessary. This paper defines the completely mixed, fluidized culture process and its mechanisms. An experimental procedure for establishing design criteria based on process kinetics is presented. An example of data obtained from an actual petrochemical waste using this procedure is illustrated graphically.
Fire and Quench Tests of Refinery Valves
Authors: Heckler N. B. , Petkus J. J. , Randall P. N. , Tisinai G. F.
Published: December 2011

Valve bodies made of seven materials from five suppliers were thermal-shock tested by heating to 1300 F, 1500 F, 1600 F, or 1800 F and then quenching with a fire-hose stream. None cracked when quenched from 1300 F. Nodular, malleable, and gray cast iron cracked when quenched from 1600 F and 1800 F, because of the combination of differential-cooling stresses and the stresses produced by the transformation of high-carbon austenite to martensite. Austenitic cast nickel iron, with either flake or spheroidal graphite, cast carbon steel, cast 5% chromium-0.5% molybdenum steel, and cast 9% chromium-1% molybdenum steel did not crack in any of the tests. Spheroidal graphite structures produced by treatment with magnesium or with yttrium behaved the same. Based on a consideration of both these results and the melting temperature of the materials, ferritic cast-steel valves are classed as safe for refinery hydrocarbon service, austenitic cast-nickel-iron valves as intermediate, and cast-iron valves of any type as not safe for this service.
Thin-Shell Pressure Vessel Theoretical and Experimental Stresses
Authors: Jones Edward O.
Published: December 2011

This paper is concerned primarily with a comparison of experimental and theoretical shell-to-head junction stresses of a thin-shell pressure vessel. The portion of the vessel with which this investigation was concerned was the region at the junction of a two-to-one ellipsoidal head and a cylindrical shell. Both a discussion of the theoretical analysis and a description of the experimental investigation are included in the paper.
Temperature Gradients in Skirt Supports of Hot Vessels
Authors: Bergman D. J.
Published: December 2011

A discussion of the variables involved in the temperature gradient along a skirt support for a hot vessel is presented. A method is presented for reasonably approximating the maximum gradient since the temperature curve is rarely linear. For guidance in applying the formula and to illustrate the effect of some of the variables, several basic cases are calculated, using three different skirt support thicknesses and considering bare, fireproofed, and insulated types of skirts. Having a formula for a steady-state temperature along the length of a skirt, it is possible by means of mathematical manipulations to obtain the value of the radius of curvature of the neutral axis at any point. Using this, it is then possible to calculate the axial tension and compression stresses on the inside and outside of a free skirt wall.
An Evaluation of the Fixed Point Method of Vibration Analysis for a Particular System With Initial Damping
Authors: Bogy D. B. , Paslay P. R.
Published: December 2011

The maximum steady-state response of a particular linear damped two-degree-of-freedom vibratory system is minimized by determining the optimum damping constant for a single damper. This is accomplished by both a well-known approximate method and by an exact numerical method. Since the approximate method does not take into account the damping which is initially in the system, attention in this analysis is directed to determining the influence of the initial damping on the optimum value for the single damper. In order to make direct comparison of the methods, a system was chosen in which an exact numerical determination of the optimum damping was possible. The results of the investigation show for the particular case considered that, although the value of the damping constant for the optimum damper increases considerably as initial damping is included in the system, use of the value obtained for the initially undamped case would give values of the maximum steady-state response within 10 percent of the optimized value for the range of initial damping commonly encountered.