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RESEARCH PAPERS

J. Eng. Ind. 1970;92(2):257-262. doi:10.1115/1.3427726.

Over a broad range of temperatures and pressures the Joule-Thomson coefficients have been computed from the enthalpy equations developed by the International Formulation Committee, 1967. The computed data are compared with the available experimental determinations, including some hitherto unpublished values.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):263-268. doi:10.1115/1.3427727.

The pendulum probe is described. It is an instrumented device that penetrates polar ice sheets for remote measurements of geophysical parameters. It can only move downward by melt penetration; its instrumentation is permanently installed, sealed in the ice. The power requirements and operating costs are derived from the heat transfer analysis. The pendulum steering principle, which assures a vertical probe attitude and course, also explains its performance flexibility. The results from the first trials verify the probe’s feasibility and supply additional design information. The probe offers a unique opportunity for access to, and study of, the Antarctic Ocean waters under the Ross and Filchner ice shelves.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):269-274. doi:10.1115/1.3427728.

Penetrations, in the pressure-resistant structure of a submersible, disturb the stress condition in the shell and may cause a premature failure. In this paper, two types of finite-element solutions are used to predict the stress distribution near view port openings in spherical shells under external pressure. Results of experimental stress analyses are also given and compared to the theoretical results.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):275-280. doi:10.1115/1.3427729.

The residual stresses induced by cold-rolling flat plate to a cylindrical shell are investigated for initially elastic, perfectly plastic materials. Expressions for the nonlinear stress-strain curves induced by the residual stresses that are effective in the rolled condition are derived by theory. By means of the effective stress-strain curves reductions in the collapse pressure of cylindrical pressure vessels formed by rolling are calculated.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):281-287. doi:10.1115/1.3427730.

The paper reviews past research on pulsed high-pressure water jets and their application to breaking rock. Experiments are reported showing the input energy per unit volume required to fracture various types of rock as a function of the pertinent variables. The stagnation pressure of the liquid jets was varied from 50,000 to 5 million psi. The theories of jet penetration through water and rock are compared with experimental results. The feasibility and potential advantages of using pulsed water jet equipment for ocean-floor excavation are discussed.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):288-292. doi:10.1115/1.3427731.

In January of 1969 under contract to the Naval Civil Engineering Laboratories (NCEL), TRW delivered to Project TEKTITE an underwater surveying system which utilized a portable, pulsed ion, argon gas laser as the reference light source. The intent of the system was to demonstrate the feasibility of conducting standard surveying operations by constructing several different size rectangles on the floor of the ocean and measuring the contours in the area of these rectangles. In addition, the actual location of the laser and the orientation of the rectangular plot was to be accurately located relative to reference points on a shoreline considered inaccessible to the divers. The Underwater Laser Surveying System (ULSS) has successfully met or exceeded all design objectives.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):293-302. doi:10.1115/1.3427732.

The analysis method described in Part 1 of the present paper is designed to handle the general case of an axisymmetric shell under axisymmetric loadings. Incremental approach is used under the consideration of the first order approximation in determining the tangent stiffness characteristics of the finite element. Effects of strain hardening, both isotropic and kinematic, are included. In order to account for instability and large accumulated deformations during the loading of the structure, the effect of the initial stress on the element stiffness is included. Incremental principle of virtual work is used to derive the working equations. A computer program is then designed and utilized to generate the design charts for formed heads of pressure vessels of various configurations. Part 2 of the present paper will give a detailed description of the numerical techniques used to apply the theory developed in Part 1. Additional significant sample problem solutions will be given in Part 2.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):303-308. doi:10.1115/1.3427733.

The problem of two normally intersecting cylindrical shells subjected to internal pressure is considered. The differential equations used for the shells are solved subject to the boundary conditions imposed along the intersection between the two cylinders. Details of a procedure for obtaining a numerical solution are given. Numerical results for a radius ratio of 1:2 are presented. Problems encountered in the numerical computation are discussed and the results of the analysis are compared with experiment.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):309-316. doi:10.1115/1.3427734.

Sixteen ASME standard torispherical heads attached to cylinders and subjected to internal pressure are analyzed as elastic and/or elastic-plastic shells using a new finite element. As basic elements, thin-walled frusta with curved meridians having common tangents and radii at the nodal circles are employed assuring good accuracy of the results. In the plastic analysis each wall-thickness was subdivided into concentric lamina in order to monitor the behavior of the material. The incremental law of plasticity in conjunction with the Mises yield condition and the associated flow rule were used in the inelastic range. The results of the analysis are presented in detail and are compared with the provisions of the ASME Pressure Vessel Code.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):317-327. doi:10.1115/1.3427735.

The matrix displacement approach of the finite element method is applied to the analysis of deformations and stresses in pressure-vessel type structures. Particular reference is made to structures with rotational symmetry, both under axisymmetric and unsymmetric loading and temperature distribution, for which two classes of structural elements for the idealization of solids and membrane shells are described. A survey of some finite elements used for the analysis of more general pressure vessel structures is conducted. Several examples of axisymmetric and nonsymmetric structures are included to demonstrate the versatility and power of the method.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):330-338. doi:10.1115/1.3427738.

The large scatter emerging from KIc measurements for heavy walled pressure vessel steels is examined in view of new data for A533B. Extensive plastic flow data at −220 deg F and 80 deg F has revealed a marked, and apparently harmonic, flow strength variation repeated at strain rate intervals in ratio of about 20. The tension skewed path over these ridges is related to the KIc behavior, for which a corresponding variational pattern with loading rate K̇ is observed. The variational pattern, or rate spectrum effect, is large compared to the average speed sensitivity of KIc , suggesting that transition temperatures values could be measured at a more moderate, though rapid, loading rate to avoid the inertial ringing effects of impact.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):339-349. doi:10.1115/1.3427739.

This paper describes the application of the boundary point least squares approach to the plane stress analysis of tube sheets with either mechanical or thermal loads. The paper includes a derivation of appropriate stress functions, a discussion of the point matching and boundary point least squares methods, and a description of the application of the method to the analysis of different hole configurations in tube sheets. It concludes with numerical results obtained from the analysis of the thermal stresses near the divider lane of a tube sheet from a two-pass heat exchanger.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):350-356. doi:10.1115/1.3427740.

A theoretical study is carried out to examine the influence of plate thickness on the stress state ahead of a through crack in a bent plate of infinite extent. The approach used rests on a theory in which no restrictions are placed on the mode of the stress distribution across the thickness of the plate. A knowledge of the local stresses or moments of the ensuing stress or moment intensity factor is held important in connection with modern views on the theory of crack propagation. The results show that the bending stresses local to the crack tip are drastically changed when the plate thickness increases from zero to some infinite, but small value. This is evidenced by the high elevation of the local moments as the ratio of plate thickness to crack length is perturbed slightly from zero.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):357-365. doi:10.1115/1.3427741.

This paper contains exact solutions for the transient temperature distribution and the associated quasi-static thermal stresses and deformations which arise in a thin circular disk of finite radius subjected to a continuous point heat source acting on its periphery. It has been proven in this paper that the solutions of this type of problem may be obtained by integrating the time variable of the corresponding solutions in the case of an instantaneous point heat source. The solutions are given in the form of double infinite series and graphical representations of the solutions in dimensionless terms are included. Reference is made to methods of applying the solutions to shapes other than disks. The solutions are pertinent to problems which occur in welding engineering and modern nuclear technology.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):366-373. doi:10.1115/1.3427742.

An objective evaluation of the thermal capacity of 36 in. CR wheels braked with COBRA brake shoes is presented and related to that of wheels braked with cast metal brake shoes. The wheel tread conditions, hardness and macrostructure of the rim, and residual stress patterns, which developed from high speed dynamometer braking-were investigated through three progressive test series. The results indicate that the thermal capacity of wheels braked with COBRA brake shoes far exceeds limits previously established for cast metal shoes.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):375-384. doi:10.1115/1.3427747.

With the growth in the use of standardized freight containers by the maritime operators along with increased use in domestic rail freight operations, a need developed for a rail freight car to handle this traffic interchangeably with domestic piggyback traffic. This paper reviews the approach that was taken to evolve this design by (a) the initial writing of a short set of general specifications, (b) the purchase from each of four car builders of a prototype which embodied their individual ideas, (c) the laboratory testing of each prototype under one testing specification, (d) a period of service testing for each prototype, (e) the writing of final specifications for a production car on the basis of that which was learned during the laboratory and service testing, (f) the final performance testing of the production model. Data on end wall force measurements on containers, longitudinal restraint force, and trailer kingpin forces at various speeds of coupling impacts are presented for the final production design as well as for the tests on the four prototypes.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):385-390. doi:10.1115/1.3427748.

External disturbances, as well as internal ones, cause a relative motion between the cutter and workpiece and thereby influence detrimentally the surface finish and machining accuracy. By properly mounting the machine tools upon soft isolators thus reducing the system’s natural frequencies, the amplitude of relative displacement between the cutter and workpiece can be decreased, thereby improving surface finish and accuracy.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):391-398. doi:10.1115/1.3427752.

Experiments were conducted involving the upsetting of solid cylinders and rings of annealed SAE 1040 steel at room temperature for various end conditions. Measurements were made on the displacement distributions at the tool-workpiece interface, and on the development of barreling and strain variations at the free surface. Crack formation at the free surface was observed. The relationship between friction at the interface, deformation characteristics, and fracturing is discussed, and a tentative analysis is given for formulating the strains at the free surface, based on the experimental measurements for upsetting solid cylinders.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):400-402. doi:10.1115/1.3427755.
Abstract
Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):403-410. doi:10.1115/1.3427758.

Two solutions for the detailed mechanics of tube extrusion are presented. One is based on the theoretical velocity field, and the other on the flow field observed experimentally. The theoretical solution makes use of admissible velocity fields containing no velocity discontinuities. Experimental flow patterns are obtained for commercially pure lead and a superplastic alloy of the eutectic of lead and tin. The two solutions are compared in terms of velocity components, grid distortions, and strain and stress distributions, and very good agreement between the two solutions is revealed.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):412-417. doi:10.1115/1.3427761.

Attempts have been made to predict loads in deep drawing Ti–6Al–4V, AISI 304, and Inconel X taking into account anisotropy and work-hardening characteristics. This has been accompanied by a comprehensive series of tests on these materials in different thicknesses (0.030–0.070 in.) using a variety of lubricants at room temperature. Draw-ability and agreement of predicted loads with those observed are seen to depend on a variety of factors. Most satisfactory agreement between prediction and observation is seen with the strongly anisotropic titanium alloy. Of the lubricants examined, polyethylene sheet and a molybdenum disulfide suspension in an acrylic resin appear to be most effective. Further work is proceeding on elevated temperature drawing.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):419-426. doi:10.1115/1.3427764.

The deformability of brittle composites, including a fiber-reinforced material, and the effect of plastic deformation on the tensile strength of such materials is investigated. The materials of interest are high-strength steel, carbide, and a composite of aluminum reinforced by 10 vol percent of Al3 Ni fibers of 0.7 to 0.8 μ diameter. The Al-Ni composite was produced by unidirectional solidification. The plastic deformation was performed by hydrostatic extrusion into a receiver pressure. The effect of environmental pressure in inducing sound flow in otherwise brittle material is presented. When 50 percent reduction in area in the fibrous material was introduced by extruding into a receiver pressure of at least 150,000 psi, a sound product resulted. The micrographs indicate that the voids formed by fracture of the fibers were healed by flow of the aluminum matrix. For evaluation of the tensile test results, a strength equation for fibrous materials was introduced. This equation, developed by the upper bound approach, predicts both the strength of the composite and whether fibers will fracture. Both the strength and the fracture criterion are functions of volume ratio, strength ratio of the two constituents, geometry, and environmental pressure. The upper bound equation is general and includes the “rule of mixtures” as a special case. Correlation was found between predicted and measured strength for the billets tested. In general, the fibrous material after extrusion is more ductile than “as solidified” but has a lower strength. Shorter fibers are expected to yield lower strength and increased ductility.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):428-433. doi:10.1115/1.3427768.

A theoretical thermal analysis of the grinding process is developed. The investigation considers temperature in the vicinity of chip formation and relates this temperature to the temperature experienced by the workpiece surface which remains after grinding. The relation is established by considering grinding geometry. The results indicate that temperatures predicted at the region of chip formation can be substantially greater than those which result on the surface of the remaining workpiece. Furthermore, the temperature in the workpiece at a distance of several ten-thousands below the surface are virtually unaffected by chip shear plane temperature.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):435-442. doi:10.1115/1.3427772.

A two-level fractional factorial design of experiment is introduced to investigate the effects of several variables on four responses with 16 tests for punching operation. The analysis indicates that the taper on punch bottom is not only the most significant factor affecting punch force but also interacts with another factor, the radius on die mouth. The die radius was found to be the dominating factor affecting the other three responses, i.e., the burr height, the amount of dishing, and the fracture angle. The increase of die radius will reduce burr height but increase dishing and fracture angle.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):444-451. doi:10.1115/1.3427776.

The laws of perfect and approximate similarities in metal forming indicate that perfect similarity in deforming two different materials is practically impossible to achieve. Approximate similarity, however, is easy to obtain and proves to be very useful in predicting forming loads in extrusion and forging processes. Analysis of friction in model experiments shows how interface friction can be taken into account in model studies. Backward and forward extrusion loads are predicted from plasticine model experiments, and the results are compared with data for various steels. Using published experimenal data, the load-displacement curve in a closed-die forging has been predicted by means of model theory. The agreement between predicted and actual loads is well within useful engineering accuracy.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):453-459. doi:10.1115/1.3427779.

A method is presented for the determination of the lateral distribution of pressure in thin strip rolling. A simplified three-dimensional analysis of elastic deformation of the rolls is developed for use in the method. Pressure in the roll edge contact regions (in underface rolling), as well as in the roll-strip contact region, is considered. In the case of four-high, planetary, and Sendzimir-type mills, the lateral distribution of pressure between the work roll and backup rolls is also found. Calculated results indicate lateral pressure distributions which have peak values at each edge of the strip with a minimum at the center. The degree of this nonuniformity depends on roll geometry and configuration. Partition of the total rolling force between roll-strip contact and roll edge contact in underface rolling is also determined. Since interroll heat transfer is dependent on contact area, and hence, pressure, the results can also aid the determination of lateral temperature distributions in the rolls. In addition, the method is potentially useful for a study of the influence of roll geometry and configuration on strip shape.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):461-467. doi:10.1115/1.3427782.

The results from steady-state extrusion studies with commercially pure aluminum using the visioplasticity method for analysis showed that interfacial friction between billet and tool influences the velocity distribution in the entire plastic zone. It was found that for well-lubricated billets, the tool-billet interface tends toward a stream line. It was found further that a reversal in sign of the resolved shear stresses and the coefficients of friction occurs in the interfacial material in the conical section of the die. An explanation for this anomaly has not yet been found, but it is believed that this behavior is due to the mechanism of plastic flow within the billet.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):469-479. doi:10.1115/1.3427785.

The classical slip line field solution for a two-dimensional punch is found to give a constraint factor (2.57) which is too small when the specimen beneath the punch is extensive. A new approach based on elasticity provides a constraint factor of 2.75. The new method of analysis also enables residual stresses to be estimated and indicates that plastic flow occurs not only when the specimen is loaded, but also when it is unloaded. Several details concerning the performance of hardness indenters are explained by the new theory for the first time.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):480-492. doi:10.1115/1.3427786.

A new approach to large strain plasticity problems in which the material is considered to behave in a plastic-elastic fashion, instead of as a plastic-rigid body, is applied to the axisymmetric blunt indenter. The ratio of the mean stress on the punch face to the uniaxial flow stress of the material (constraint factor C) is found to be 2.82 for an extensive specimen. However, it is shown that a small part of the punch face is elastically loaded, and if the loaded punch area is assumed equal to the size of the plastic impression, then the constraint factor to be used is 3.00 instead of 2.82. This is the value to be used in interpreting the ordinary brinell test. Hardness values are shown to be independent of the degree of friction on the face of a blunt indenter and of the elasticity of the indenter. The amount of material required beneath an axisymmetric indenter in order that there be no upward flow is found to be about 2.6 times the diameter of the impression for steel. However, the exact value depends on Young’s modulus of elasticity, Poisson’s ratio, material hardness, and the depth of the impression relative to the diameter of the indenting sphere. When two opposing axisymmetric indenters are employed, the influence of one on the other will be less than one percent when their spacing is approximately 11.5 times the indentation diameter. A blunt indenter may be defined as one which gives no upward flow in a hardness test. Upward flow should be avoided in hardness testing since it causes the mean stress on the punch face to produce a given impression to be sensitive to friction and the tendency of the metal to strain harden. Upward flow may be prevented by use of an extensive specimen relative to the depth of the impression, large indenter angle (160–180 deg), and high indenter friction (rough surface and no lubricant). The flow stress measured by a blunt indenter is that corresponding to the onset of plastic flow. When upward flow is permitted, the flow stress measured by an indentation hardness test will correspond to an appreciable plastic strain which increases as the included angle of the indenter decreases. The quantity measured by an indenter that performs with upward flow is, therefore, quite ambiguous when the material tested strain hardens.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):495-503. doi:10.1115/1.3427789.

This paper describes a comprehensive test program for the investigation of the influence of errors and variations in mesh stiffness on the peak stresses developed in spur and helical gears. The study is primarily concerned with speed effects on tooth loads in regions away from resonance. Four sets of specially designed and instrumented gears were tested in an open-loop setup. The interaction between tooth loads and system shaft torques at different operating conditions is also investigated. The results are utilized in the accompanying paper for the development of a generalized dynamic load formula for spur and helical gears.

Commentary by Dr. Valentin Fuster
J. Eng. Ind. 1970;92(2):504-514. doi:10.1115/1.3427790.

This paper deals with the development of a generalized dynamic factor for spur and helical gears operating away from system resonances. The experimental results of the tests reported in the previous paper [1] are used in conjunction with mathematical simulation of the gear system and geometrical analysis of the tooth meshing action to develop a semi-empirical formula for dynamic tooth load. The formula takes into consideration the gear geometry and manufacturing parameters as well as the dynamic characteristics of the system.

Commentary by Dr. Valentin Fuster

DISCUSSIONS

Commentary by Dr. Valentin Fuster
Commentary by Dr. Valentin Fuster
Commentary by Dr. Valentin Fuster
Commentary by Dr. Valentin Fuster
Commentary by Dr. Valentin Fuster

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