Showing papers in "Archive: Journal of Mechanical Engineering Science 1959-1982 (vols 1-23) in 1965"
TL;DR: The results of a number of previous investigations of the discharge characteristics of parallel-bore orifices with length/diameter ratios up to 10 and Reynolds numbers up to about 105 are collected as mentioned in this paper.
Abstract: The results of a number of previous investigations of the discharge characteristics of parallel-bore orifices with length/diameter ratios up to 10 and Reynolds numbers up to about 105are collected ...
268 citations
TL;DR: Starting from Flugge's three equations of motion for a uniform thin cylindrical shell, this article gave a general solution, from which the dependence of natural frequencies on shell dimensions and m...
Abstract: Starting from Flugge's three equations of motion for a uniform thin cylindrical shell, the paper gives a general solution, from which the dependence of natural frequencies on shell dimensions and m...
116 citations
TL;DR: In this article, an experimental investigation into the lubricating action of carbon tetrachloride when cutting copper for a carefully selected range of controlled conditions has enabled the formulation of a fundamental specification for a cutting lubricant.
Abstract: An experimental investigation into the lubricating action of carbon tetrachloride when cutting copper for a carefully selected range of controlled conditions has enabled the formulation of a fundamental specification for a cutting lubricant. In this specification, a new proposal has been made concerning the penetration of the fluid to the contact regions of the cutting tool. The penetration rate of a neat chemical compound chosen on the basis of this fundamental specification appears to behave as predicted when applied during the machining of copper.
108 citations
TL;DR: The origin of the vibration generated within an extensive bank of tubes that run transverse to the direction of gas flow through a boiler shell and whose movement is small enough in amplitude to ha... as mentioned in this paper.
Abstract: The origin of the vibration generated within an extensive bank of tubes that run transverse to the direction of gas flow through a boiler shell and whose movement is small enough in amplitude to ha...
98 citations
TL;DR: In this paper, a method of computing the natural frequencies of vibration of flat plates of arbitrary shape is outlined in which the plate is considered as an assemblage of elements and stiffness and inertia matrices are derived for a rectangular isotropic plate element of uniform thickness.
Abstract: A method of computing the natural frequencies of vibration of flat plates of arbitrary shape is outlined in which the plate is considered as an assemblage of elements.Both stiffness and inertia matrices are derived for a rectangular isotropic plate element of uniform thickness, and these matrices are used to find the natural frequencies of square plates subject to various boundary conditions. Comparison of finite element frequencies with known exact, experimental and energy solutions shows the method to give good results even for relatively few elements.
65 citations
TL;DR: In this article, an analysis of the thrust forces occurring during tool vibration is proposed, based on the assumption that there are two components to the oscillating thrust force: a component proportional to, and in phase with, the oscillations in undeformed chip thickness and a component, caused by contact between a small area of the tool flank and the freshly cut work surface.
Abstract: When tool vibration occurs during machining both the undeformed chip thickness and the cutting forces have oscillating components. An examination of previous work reveals that both the relative phases and amplitudes of the oscillating forces and the oscillating undeformed chip thickness can be affected appreciably by changes in frequency. The explanations for this behaviour which have been put forward are not entirely consistent with previous experimental evidence. In the present work an analysis of the thrust forces occurring during tool vibration is proposed. The analysis is based on the assumption that there are two components to the oscillating thrust force: (1) a component proportional to, and in phase with, the oscillations in undeformed chip thickness and (2) a component, caused by contact between a small area of the tool flank and the freshly cut work surface, which leads the oscillation in undeformed chip thickness by 90°. Experimental results are presented which validate the assumptions made in ...
58 citations
TL;DR: In this paper, a combined free and forced convection heat transfer for laminar water flow in horizontal tubes was investigated, and the experimental data obtained do not agree with existing co-existing co...
Abstract: This paper describes an investigation into combined free and forced convection heat transfer for laminar water flow in horizontal tubes. The experimental data obtained do not agree with existing co...
43 citations
TL;DR: The evolution and advantages of three previously described bifurcated power transmission systems are outlined, and three new systems are described, analysed, and compared and are shown to possess identical characteristics.
Abstract: The evolution and advantages of three previously described bifurcated power transmission systems are outlined. Three new systems are then described, analysed, and compared. Four of these systems, though different, are shown to possess identical characteristics. The analysis used may be applied to other problems, and curves for design use are presented.
26 citations
TL;DR: In this article, lower bound estimates of the shakedown pressure for a flush radial cylinder-sphere intersection were found by applying Melan's theorem and making use of elastic solutions already in existence.
Abstract: Lower bound estimates have been found of the shakedown pressure for a flush radial cylinder-sphere intersection. This has been achieved by applying Melan's theorem and making use of elastic solutions already in existence. Results are presented in compact graphical form.
26 citations
TL;DR: In this article, the ability of various techniques for extracting the modes and frequencies from resonance test results is investigated under the assumption that this condition does exist, and each of the various techniques are investigated.
Abstract: It is difficult (if not impossible) to find the principal modes, natural frequencies and levels of damping of a structure by means of a resonance test if the structure happens to possess two (or more) close natural frequencies. Under the assumption that this condition does exist, the ability of each of the various techniques for extracting the modes and frequencies from resonance test results is investigated.
23 citations
TL;DR: A modal balancing technique may be used for all modes through whose critical speeds the shaft runs, and then an averaging technique can account for the remaining modes.
Abstract: Details are given of a practical technique that has been developed for the balancing of large flexible rotors. The special conditions that arise when such a rotor is borne in bearings from which vibration readings are taken are described. A modal balancing technique may be used for all modes through whose critical speeds the shaft runs, and then an averaging technique can account for the remaining modes.
TL;DR: In this article, an exact solution verified by obtaining coincident upper and lower bounds has been calculated for the limit pressure for a protruding cylindrical nozzle in a spherical pressure vessel.
Abstract: Using the one-moment limited interaction surface, an exact solution verified by obtaining coincident upper and lower bounds has been calculated for the limit pressure for a protruding cylindrical nozzle in a spherical pressure vessel.Using a particular mechanism configuration involving the sphere and the external part of the branch which covers a wide range of the parameters r/R, R/T and t/T, a comprehensive study of the effect of the internal protrusion has been made. Results of the limit pressure for a wide range of parameters are presented.
TL;DR: In this paper, the conformity of the Wildhaber-Novikov-style profile gears was examined and it was indicated that the contact area may be a banana shape rather than the ellipse hitherto assumed.
Abstract: The conformity of circular-arc profile gears of the Wildhaber-Novikov sort is examined It is indicated that the contact area may be a banana shape rather than the ellipse hitherto assumed Two consequences of this are that too small a difference between the profile radii may reduce the useful conformity, and that it is not possible to increase the torque capacity per unit face width indefinitely by reducing the helix angle
TL;DR: By using steady flow relations including pressure loss coefficients, a method is developed for calculating wave action in a duct with a gauze as mentioned in this paper, and both steady and non-steady flow experiments for five gauzes are described.
Abstract: By using steady flow relations including pressure loss coefficients a method is developed for calculating wave action in a duct with a gauze. Both steady and non-steady flow experiments for five gauzes are described. The results of the non-steady flow tests showed excellent agreement between the predicted indicator diagrams, using the steady flow pressure loss coefficients, and the measured indicator diagrams. The methods described in the paper may be used by engine designers to predict the effect of gauzes or similar devices on the wave action in exhaust systems of internal combustion engines.
TL;DR: In this paper, a tensile impact machine for tensile tensile testing at impact rates of tensile strain was described and the results were compared with results obtained at conventional strain rates.
Abstract: The techniques that have been employed in the construction of tension testing machines for use at impact rates of strain are summarized. The difficulties involved are briefly reviewed. The practicability of applying magnetic forces to the generation of dynamic loads is discussed and a new type of tensile impact machine, in which such forces are used, is then described. It is shown that with this machine, small specimens may be yielded in times as short as 5 μs and at strain rates of 1000 per second and above. Reliable stress–strain curves are presented for both ferrous and non-ferrous materials at various test temperatures and comparison is made with results obtained at conventional strain rates.
TL;DR: One-dimensional quasi-steady flow theories for flow through an orifice in a pipe are developed in this article, which can be used with wave action calculations using the methods of characteristics.
Abstract: One-dimensional quasi-steady flow theories for flow through an orifice in a pipe are developed. These theories are presented in a form to be used with wave action calculations using the methods of characteristics. Steady flow experiments are described for determining the effective area of the orifice and the location of the plane of the pressure recovery. Non-steady flow tests using a single unit of a pulse generator are described. The results of non-steady flow experiments in the pipe are compared with the calculated pressure diagrams using a quasi-steady flow one-dimensional theory. These showed that the theory may be used for predicting the overall wave action in the pipe. In the plane of the enlargement, downstream of the orifice, the theory did not give an exact prediction of the pressure, particularly with small orifice area to pipe area ratios and high overall pressures. For small pressure changes, however, it is considered that the theory was satisfactory and may be used as the basis for calculati...
TL;DR: In this article, the relationship between maximum strain, load and deflection in the plastic region was investigated on axially loaded expansion bellows. But the results were limited to the case of a single balloon.
Abstract: Tests were performed on axially loaded expansion bellows in order to obtain the relationship between maximum strain, load and deflection in the plastic region. A numerical method, previously propos...
TL;DR: In this article, a strut with a centrally located hole was determined by employing photoelastic measurements and single spark photography together with controlled repeated loadings on Columbia resin CR-39 models was utilized to obtain the dynamic fringe pattern.
Abstract: Dynamic stress concentrations were determined for a strut with a centrally located hole by employing photoelastic measurements. Single spark photography together with controlled repeated loadings on Columbia resin CR-39 models was utilized to obtain the dynamic fringe pattern. In general, it was found that the dynamic stress concentrations differed significantly from the static stress concentrations. The difference depended upon the geometry of the model and the location at the boundary of the hole.
TL;DR: In this article, a variant of Kryloff and Bogoliuboff's method is used to analyse the periodic vibrations of a non-linear two-degree-of-freedom system which is an idealization of the crankshaft of a two-cylinder in...
Abstract: A variant of Kryloff and Bogoliuboff's method is used to analyse the periodic vibrations of a non-linear two-degree-of-freedom system which is an idealization of the crankshaft of a two-cylinder in...
TL;DR: A graphical method of analysis of surface wave instability in grinding is presented in this article, which is characterized by uneven wear of the wheel, causing surface waves to form about its circumference.
Abstract: A graphical method of analysis of surface wave instability in grinding is presented. This form of instability is characterized by uneven wear of the wheel, causing surface waves to form about its circumference. A progressive deterioration in the finish of the work results, together with an increase in the level of vibration. This is a type of self-excited vibration, and is not due to inhomogeneities in the wheel.The factors affecting the number of waves which can build up are discussed. The method of analysis is applied to a cylindrical grinding machine, and the results obtained are compared with those obtained from an experimental investigation.
TL;DR: In this article, a photoelastic surface coating with a reflection polariscope was used to estimate the distribution of the maximum shear strain, y, near the crack tip, during both loading and unloading of the sheet.
Abstract: Strain distributions around fatigue cracks in different sheet metals have been obtained by using a photoelastic surface coating with a reflection polariscope. It is shown that an estimate of the distribution of the maximum shear strain, y, near the crack tip, during both loading and unloading of the sheet, requires a knowledge of only the stress-strain curve of the material and the theoretical elastic plane-stress solution.
TL;DR: In this paper, the authors measured the thermal conductivity of five samples of copper rod which had been strained to different degrees by cold drawing and found that the most highly strained sample (drawn to 50 per cent reduction of area) was about 11 per cent lower than that of annealed material.
Abstract: Measurements were made of the thermal conductivity of each of five samples of copper rod which had been strained to different degrees by cold drawing. The measured thermal conductivity of the most highly strained sample (drawn to 50 per cent reduction of area) was about 11 per cent lower than that of annealed material.The flow of heat through a stationary metal-to-metal joint is inhibited by the reduced conductivities of the plastically deformed surface asperities forming the real contact points within the joint. The complex straining processes involved in the mating of asperities make it difficult to predict quantitatively the overall effect on a joint's conductance, but the reduced thermal conductivities may be partially responsible for the very low joint conductances previously attributed to changes in metal ‘hardness’.
TL;DR: In this article, the results of heat transfer measurements taken on a two-dimensional supersonic parallel diffuser have been measured for a range of initial total pressures, and the effects of varying the area of the diffuser cross-section for the same upstream generating nozzle have also been studied.
Abstract: This paper presents the results of heat transfer measurements taken on a two-dimensional supersonic parallel diffuser. The wall static pressure distributions and the corresponding heat transfer coefficients and fluxes have been measured for a range of initial total pressures. The effects of varying the area of the diffuser cross-section for the same upstream generating nozzle have also been studied. Mach number profiles measured at sections along the diffuser show that in the presence of shock waves and a positive pressure gradient the flow is very much underdeveloped. In general, the mean level of heat transfer is found to be much greater than that predicted by conventional empirical equations for subsonic pipe flows with zero pressure gradient. Further, on comparison between normal and oblique shock diffusion the former is found to give the higher level of heat transfer.
TL;DR: In this paper, three types of bridge are discussed, the direct current, the transformer ratio and the hydraulic bridge, and methods of sampling small quantities of the main flow are described for the null method; when the two thermometer...
Abstract: Hydraulic losses experienced by fluids in passing through machines effectively raise the temperature. The thermodynamic method of testing is basically a way of determining these losses by measuring temperature rise. When pressure change through a machine is measured along with temperature, the enthalpy change is known and the hydraulic efficiency can be evaluated. Knowledge is necessary of certain thermodynamic properties of the liquid which change with pressure and temperature. Heat transfer between the machine and its surroundiings is assumed to be negligible.Apparatus is described for use in several different applications of the method, but principally in the thermometric and null methods. Temperature change has usually been measured by resistance thermometers in various bridge networks. Three types of bridge are discussed, the direct current, the transformer ratio and the hydraulic bridge. Methods of sampling small quantities of the main flow are described for the null method; when the two thermometer...
TL;DR: In this paper, the velocity of propagation of very long waves in flexible liquid-filled tubes lying on a flat horizontal surface was investigated, where the tubes considered are of sufficiently small rigidity that their cross-sectional shape is determined by the internal hydrostatic pressure, lying quite flat when empty.
Abstract: This paper deals with the velocity of propagation of waves in flexible liquid-filled tubes lying on a flat horizontal surface. The tubes considered are of sufficiently small rigidity that their cross-sectional shape is determined by the internal hydrostatic pressure, lying quite flat when empty.It is shown that at low internal pressures very long waves propagate essentially as gravity waves in a canal. The wave velocity increases with the internal pressure and, at the same time, is increasingly affected by the extensibility of the tube wall. At very high pressures, long waves propagate essentially as axisymmetric waves in distensible circular cylinders. The calculated and measured velocities of propagation of very long waves are in substantial agreement.The system is frequency dispersive and the wave velocity rapidly increases with the wave number. An approximate analysis is presented, applying only when the tube contains little liquid, establishing the mechanism underlying this behaviour. This is qualita...
TL;DR: A design is proposed and analysed for an hydraulic control system whose valve is operated in such a way as to provide time optimum system response to step inputs of various magnitudes for various inertial loads.
Abstract: A design is proposed and analysed for an hydraulic control system whose valve is operated in such a way as to provide time optimum system response to step inputs of various magnitudes for various inertial loads. It is attempted to operate initially with maximum acceleration, followed by maximum deceleration within the constraints imposed in avoiding cavitation. Analytical solutions are found for the non-linear equations of motion describing this operation of the system. The theoretical limitations and practical implications of the work are discussed.
TL;DR: In this paper, the axi-symmetric configuration of the parallel diffuser was investigated and it was shown that only very short lengths of duct are necessary to achieve full static pressure recovery in both the single shock and the oblique shock regimes.
Abstract: This paper extends the investigation of the supersonic parallel diffuser previously reported by Martin and Baker (I)‡ and Baker (2) to cover the case of the axi-symmetric cross-section. The flow patterns and the wall static pressure distributions appear broadly to correspond to those which occur in the parallel diffuser of rectangular cross-section. But the axi-symmetric diffuser is found to have a wider operating range (in terms of overall blowing pressure ratio) before the single shock gives way to an oblique shock system, and this permits higher optimum recovery of static pressure. In the axi-symmetric configuration, only very short lengths of duct are necessary to achieve full static pressure recovery in both the single shock and the oblique shock regimes. The use of short diffusers would lessen the cooling problems of large-scale jet engine test facilities, in which exhaust jets must be recompressed at elevated temperatures.