Showing papers in "Journal of Strain Analysis for Engineering Design in 1983"
TL;DR: In this paper, a resume of the results available in the literature for the stresses resulting from frictionless loading by Hertz pressures is given, and new convenient forms are given for the complete stress field, in the general elliptical patch case.
Abstract: A resume is given of the results available in the literature for the stresses resulting from frictionless loading by Hertz pressures. The problem is posed formally in tensor notation and new convenient forms are given for the complete stress field, in the general elliptical-patch case.
120 citations
TL;DR: In this article, the authors reviewed the literature for the problem of two contacting bodies, suffering Hertzian contact and with an assumed proportional shear, and the general case of the proble...
Abstract: Results available in the literature for the problem of two contacting bodies, suffering Hertzian contact and with an assumed proportional shear, are reviewed. The general case of the proble...
69 citations
TL;DR: In this paper, the authors deduced the values of stresses resulting from point or line Hertzian contact (including frictional traction) as a special case of the general elliptical geometry problem, and compared with known solutions.
Abstract: The values of stresses resulting from point or line Hertzian contact (including frictional traction) are deduced as a special case of the general elliptical geometry problem, and are compared with known solutions.
68 citations
TL;DR: In this article, the basic theoretical approach in the mechanics of external or inside-to-outside inversion of circular tubes is examined and extended by the introduction of two additional and previously unknown concepts.
Abstract: The basic theoretical approach in the mechanics of external or inside-to-outside inversion of circular tubes is examined and extended by the introduction of two additional and previously un...
48 citations
TL;DR: In this article, the residual stresses obtained during shot-peening are directly proportional to the treated material's hardness, and the depth of material influenced depends on the velocity of approaching shot.
Abstract: It is shown that the residual stresses obtained during shot-peening are directly proportional to the treated material's hardness, and that the depth of material influenced depends on the velocity of approaching shot. The relationship between the shot size and depth hardened is developed, and experimental evidence is provided to verify the major points of the analysis. Useful curves, enabling the variation of residual stress with depth to be estimated, are included, and this enables the shot-peening treatment to be matched to alleviate any subsequent contact-pressure loading that the material may experience during service.
32 citations
TL;DR: In this paper, the hole geometry has been modified to effect stress reductions as high as 22 per cent by adding auxiliary holes on either side of the original hole, which creates two more regions of stress concentration in the plate.
Abstract: The stress concentration around a circular hole in a plate can be reduced by up to 21 per cent by introducing auxiliary holes on either side of the original hole. But this approach of auxiliary holes creates two more regions of stress concentration in the plate.In the present study, the hole geometry has been modified to effect stress reductions as high as 22 per cent. The problem has been analysed numerically by the finite element method and experimentally by two-dimensional photoelasticity. It has been observed that by making the hole oblong in the direction of loading, a high order of reduction in stress concentration around the hole can be obtained.
29 citations
TL;DR: In this article, a boundary element formulation for the solution of viscoplasticity problems in the presence of large strains and displacements is presented, based on an appropriate form of Betti's reciprocal theorem together with a time marching scheme using an updated Lagrangian approach.
Abstract: A boundary element formulation for the solution of viscoplasticity problems in the presence of large strains and displacements is presented in this paper. The BEM formulation is based on an appropriate form of Betti's reciprocal theorem together with a time marching scheme using an updated Lagrangian approach. Numerical results are presented for various plane strain and plane stress viscoplasticity problems. Results from the boundary element analysis are compared to those from the finite element analysis with regard to accuracy and computational efficiency.
28 citations
TL;DR: The boundary integral equation (BIE) numerical method for linear elastic stress analysis is applied to axisymmetric problems which also involve temperature variations due to steady-state thermal conduction as mentioned in this paper.
Abstract: The boundary integral equation (BIE) numerical method for linear elastic stress analysis is applied to axisymmetric problems which also involve temperature variations due to steady-state thermal conduction. The boundary of the two-dimensional solution domain is discretized into isoparametric quadratic line elements, which provide an excellent modelling capability. Satisfactory agreement is obtained with both exact analytical solutions for test problems and numerical results obtained by the finite difference and finite element methods. The BIE method is applied to the problem of a hollow cylinder with an external semi-circular groove, subjected to axial tensile loading and a temperature difference across the cylinder wall. The results emphasise the very high stress concentrations which can be obtained when the effects of thermal and mechanical loading are superimposed. An important practical advantage of the BIE method is the small amount of labour involved in preparing the mesh data.
28 citations
TL;DR: In this paper, a re-examination of some 85 past experiments on the elastic buckling of axially loaded ring-stiffened cylinders shows the existence of two distinctive behavioural regimes.
Abstract: Re-examination of some 85 past experiments on the elastic buckling of axially loaded ring stiffened cylinders shows the existence of two distinctive behavioural regimes. Lightly stiffened cylinders, like isotropic cylinders, buckle into non-axisymmetric modes having long axial wavelengths at loads that are sensitive to the precise magnitudes of small initial imperfections. Heavily stiffened cylinders are characterised by snap buckling into axisymmetric modes which, for elastic behaviour at least, show only limited sensitivity to initial imperfections.Each of these characteristics is shown to be predicted by the recently developed ‘reduced stiffness analysis’ method, which, despite the relatively perfect nature of test specimens, predicts reliable lower bounds to the experimental scatter. Taken together with the previously demonstrated empirical validity of the reduced stiffness analysis for the prediction of buckling modes and lower bounds to buckling loads for both isotropic and stringer stiffene...
26 citations
TL;DR: In this paper, the analytical and numerical formulation of the boundary integral equation (BIE) method is outlined for the general case in linear elasticity, using this method, three-dimensional linear elastic fracture mechanics analyses of a rotating disc with a corner crack at its bore are carried out.
Abstract: The analytical and numerical formulation of the boundary integral equation (BIE) method are outlined for the general case in linear elasticity. Using this method, three-dimensional linear elastic fracture mechanics analyses of a rotating disc with a corner crack at its bore are carried out. The cases considered are for a disc with external to internal radius ratio of 8 and with thickness equal to the diameter of the central bore. Two different crack shapes, namely, a quarter-circular crack and a quarter-elliptical crack with ellipse aspect ratio of 0.75, are analysed. For each of these shapes, corner cracks penetrating 50 per cent and 75 per cent of the disc thickness are treated. Stress intensity factor solutions for these cracks are presented for the centrifugal loading condition, as well as when the disc is subjected to a radial tensile stress at its external circumferential periphery.
25 citations
TL;DR: In this paper, three-dimensional, frozen-stress, photoelastic models of 1 in. BSW studs and tapped blocks have been loaded axially and in torsion.
Abstract: Three-dimensional, frozen-stress, photoelastic models of 1 in. BSW studs and tapped blocks have been loaded axially and in torsion. Detailed distributions of axial, principal, and shear stresses show that, as expected, the greatest stresses occur near the front end of engagement, but there are secondary peaks near the back end due to the stresses set up by ‘locking’ the stud at the bottom of the hole.Chamfering the first two turns of the thread of the block eliminates the stress concentration at the front of the block itself but does not reduce the stud stresses significantly. Similarly, the stresses at the back of engagement are reduced if the stud thread is chamfered.
TL;DR: The principles of the boundary integral equation (BIE) or boundary element method (BEM) are discussed in a non-mathematical way as discussed by the authors, and the technique is compared with other numerical methods.
Abstract: The principles of the boundary integral equation (BIE) or boundary element method (BEM) are discussed in a non-mathematical way The technique is compared with other numerical methods, part
TL;DR: In this paper, 50 hemiellipsoidal domes were cast in solid urethane plastic, with profiles which varied from oblate to prolate shapes and tested to failure.
Abstract: Fifty hemiellipsoidal domes were cast in solid urethane plastic, with profiles which varied from oblate to prolate shapes.The domes were subjected to external hydraulic pressure in a test tank and tested to failure. All the domes appeared to fail through elastic instability, the oblate shapes failing axisymmetrically, and the prolate shapes failing asymmetrically in a lobar manner.The theoretical analysis was carried out via the finite element method, and stiffness matrices were developed for an axisymmetric element of constant meridional curvature. The element was capable of being applied to axisymmetric deformation or axisymmetric and asymmetric instability, and it was generated numerically.
TL;DR: The boundary integral equation (BIE) method for two-dimensional elastic-plastic stress analysis is applied to an internally pressurized thick-walled cylinder containing a radial crack as discussed by the authors.
Abstract: The boundary integral equation (BIE) method for two-dimensional elastic-plastic stress analysis is applied to an internally pressurized thick-walled cylinder containing a radial crack. Two different types of material are considered, namely, an elastic-perfectly plastic material and a work-hardening material. The loading conditions applied include the case when the internal pressure also acts on the crack faces, and the case when it does not. Results are presented showing the plastic zone development in the cylinder and the variations of the fracture mechanics parameter, the J line integral, with increasing internal pressure.
TL;DR: In this paper, the in-plane deformation of a thin, incompressible membrane undergoing an arbitrary, but finite, homogeneous deformation mode is considered, and the analysis is performed with reference to an initially square or rectangular grid of lines, since the nodes of the grid facilitate the experimental measurements.
Abstract: This article considers the in-plane deformation of a thin, incompressible membrane undergoing an arbitrary, but finite, homogeneous deformation mode. No discontinuities in the loading system are permitted, and the nature of the straining process is assumed unchanged from beginning to end. For these restricted deformation modes a technique is described whereby the equivalent strain can be evaluated by measuring the initial and final shape only of a finitely deformed grid marked on the surface of the membrane. The analysis is performed with reference to an initially square or rectangular grid of lines, since the nodes of the grid facilitate the experimental measurements. A distinction is drawn between homogeneous deformation and the special case of pure homogeneous deformation which results in the same shape change. In the latter mode a pair of principal axes can be identified which remain orthogonal during the entire deformation history; while for the former mode there is no such line pair which pr...
TL;DR: The boundary integral equation (BIE) method for two-dimensional, linear, elastic stress analysis is applied to two plane strain problems involving either incompressible or nearly-compressible materials as mentioned in this paper.
Abstract: The boundary integral equation (BIE) method for two-dimensional, linear, elastic stress analysis is applied to two plane strain problems involving either incompressible or nearly incompressible materials. One of these is a test problem with a known analytical solution, which facilitates checking of the accuracy of the numerical results. The other is the determination of compression moduli of bonded rubber blocks, for which some finite element (FE) solutions have been published previously. Comparison of the BIE and FE results suggests that the latter are increasingly inaccurate as the material behaviour approaches incompressibility. Unlike displacement-based FE methods, the BIE method is not subject to singularity problems when applied to incompressible materials.
TL;DR: The boundary integral equation (BIE) method for three-dimensional linear, elastic stress analysis is applied to some stress concentration problems associated with transverse circular holes in either hollow or solid circular cylinders subject to axial tension or torsion, also offset-oblique holes in cylinders with internal pressure.
Abstract: The boundary integral equation (BIE) method for three-dimensional linear, elastic stress analysis is applied to some stress concentration problems associated with transverse circular holes in either hollow or solid circular cylinders subject to axial tension or torsion, also offset-oblique holes in cylinders subject to internal pressure. Satisfactory agreement is obtained with some previously published experimental results, although computed maximum stress concentration factors are generally higher than those obtained experimentally. The BIE method is shown to be a very useful tool for solving three-dimensional problems of engineering stress analysis.
TL;DR: In this article, the elastic and postbuckling behavior of plate girders when subjected to shear loading is simulated using 18 small scale models, and the results showed that the models were fabr...
Abstract: Tests on eighteen small scale models which simulate the elastic and post-buckling behaviour of plate girders when subjected to shear loading are reported and discussed. The models were fabr...
TL;DR: In this article, a chill-cast, antimony-arsenic-lead alloy model material was used to investigate the monotonic and cyclic loading, uniaxial and biaaxial plasticity behaviour of a metal at elevated temperature, i.e., T/Tm ≈ 0.5.
Abstract: A chill-cast, antimony-arsenic-lead alloy model material has been used to investigate the monotonic and cyclic loading, uniaxial and biaxial plasticity behaviour of a metal at elevated temperature, i.e., T/Tm ≈ 0.5.For the lead alloy used, a post-machining heat treatment of 96h at 100 C considerably reduced the scatter in the material behaviour. Uniaxial monotonic loading tests showed that the behaviour is relatively independent of temperature and strain-rate for strains less than about 1 per cent.Under cyclic loading conditions, between fixed strain limits, a stable hysteresis loop is obtained after the first cycle for both uniaxial and biaxial stress systems. By taking into account the biaxiality ratio and the increase in yield-range caused by cyclic hardening, the uniaxial and biaxial, cyclic plasticity behaviour was reasonably accurately predicted from the uniaxial, monotonic loading behaviour.
TL;DR: In this article, the authors used the scattered light photoelastic technique to determine Mode I stress intensity factors associated with a semi-elliptical surface flaw in a plate subjected to uniaxial tension.
Abstract: The scattered-light photoelastic technique was utilized to determine Mode I stress intensity factors associated with a semi-elliptical surface flaw in a plate subjected to uniaxial tension. Stress intensity factors were experimentally determined for the point of maximum flaw penetration and the point of intersection of the flaw border with the free surface of the plate. Experimental results are compared to those obtained in a three-dimensional finite element analysis with reasonable agreement being shown.
TL;DR: In this paper, the white light speckle method is used to obtain the interior displacement at different planes of a block with a central idented load, and of a prismatic bar of square cross section under torsion.
Abstract: The white light speckle method is used to obtain the interior displacement at different planes of a block with a central idented load, and of a prismatic bar of square cross section under torsion. The problem of decorrelation of speckles due to tilt is not encountered in this method, resulting in reasonable fringe patterns, and good agreement between the displacements obtained with this method and that predicted by the theory of elasticity is found.
TL;DR: In this article, the von-Mises effective stress criterion and the Prandtl-Reuss flow rule were used for both the plastic and creep deformations, and a 4-line stress-strain relationship with a UTS value 1.48 times greater than the yield stress was used.
Abstract: Elastic, elastic-plastic, elastic-creep, and elastic-plastic-creep finite element calculations have been performed for a compact-tension specimen under plane-stress conditions. The von-Mises effective stress criterion and the Prandtl-Reuss flow rule were assumed for both the plastic and creep deformations. A 4-line stress-strain relationship with a UTS value 1.48 times greater than the yield stress was used. A strain hardening, Norton-Bailey creep law was assumed.A fairly course mesh of 8 noded, isoparametric elements was found to be adequate for determining reference stress, crack tip opening displacement, J-contour integral, and C∗-contour integral values.The UTS zone, rather than the yield zone, was found to have a significant effect on the C∗-contour integrals and CTOD rates. An approximate method of determining C∗ values was found to give reasonable results, particularly for low load cases, i.e., when the UTS zones are small. Hence, provided care is taken not to perform tests at very high loa...
TL;DR: In this article, the authors used finite element method to investigate the behavior of axisymmetric loaded projections (e.g., bolts) subjected to axial tension and bending.
Abstract: The finite element method has been used to investigate the behaviour of axisymmetric loaded projections (e.g., bolts) subjected to axial tension and bending.The results show that existing data for stepped shafts, which have the axial tension and bending loads applied remote from the region of the step, cannot be applied to loaded projections with the same geometry.For h/d (head thickness to shank diameter ratio) values greater than 0.66 and 0.41 for axial tension and bending, respectively, the stress concentration factors are independent of h/d, load position, and D/d (head diameter to shank diameter ratio) for D/d in the range 1.5 ≤ D/d ≤ 2.0. Smaller h/d values result in large increases in the stress concentration factors due to dishing of the head.
TL;DR: In this article, the time dependent variation of the stress concentration factor during creep is discussed for a visco-elastoplastic celluloid strip containing a circular hole, and the variation of stress at this stress raiser is analyzed by means of a proposed photo-viscoplasticity method for several cases of tensile loading.
Abstract: The time dependent variation of the stress concentration factor during creep is discussed for a visco-elastoplastic celluloid strip containing a circular hole. The variation of stress at this stress raiser is analysed by means of a proposed photo-viscoplasticity method for several cases of tensile loading.
TL;DR: Two boundary integral equations (BIE) methods have been applied to obtain stress intensity factor K calibrations for cracked C-shaped, split-ring (SR) and ring specimens as discussed by the authors.
Abstract: Two boundary integral equations (BIE) methods have been applied to obtain stress intensity factor K calibrations for cracked C-shaped, split-ring (SR) and ring specimens. It is shown that good agreement is achieved with experimental determinations and other information in the literature. Also fatigue crack growth studies have demonstrated that all the shapes are suitable for establishing the fatique properties in the radial direction of thick-walled tubing. The ring specimen is shown to be particularly appropriate for determining fatigue crack growth behaviour in tubes which have been autofrettaged.
TL;DR: In this article, the elastic stress concentrations in the prismatic part of key and keyway at the positions of contact between key and shaft have been derived for any likely width, thickness, and length of key, keyway fillet size, and applied torque.
Abstract: Three- and two-dimensional, photoelastic, frozen-stress models of Standard metric and inch keyed connections have been loaded in torsion. Results from models with three different key lengths are presented here and related to the axial distribution of torque transmission.Empirical equations for the elastic stress concentrations in the prismatic part of key and keyway at the positions of contact between key and shaft have been derived for any likely width, thickness, and length of key, keyway fillet size, and applied torque. A simple method of eliminating stress concentrations in the keyway end is described.
TL;DR: In this article, an elastic-plastic finite element analysis of a compact tension specimen (CTS) is presented and information on the growth of crack tip plastic zones, crack tip opening displacements, stresses and strains in the region of the crack tip, and Rice's J integral.
Abstract: Results from an elastic-plastic finite element analysis of a compact tension specimen (CTS) are presented and provide information on the growth of crack tip plastic zones, crack tip opening displacements, stresses and strains in the region of the crack tip, and Rice's J integral. The elastic-plastic crack separation energy rate GΔ is also evaluated when the crack extends at various loads by applying a crack tip node release technique.
TL;DR: In this article, a simple method is presented which gives a useful estimation of the bending suppression (the ratio of bending strain to the absolute value of the evaluated axial strain when a rod is subject to bending only) from optically measured mispositioning, and estimated differences between the gauge constants for the two strain gauges.
Abstract: Contributions from bending to the evaluated axial strain in an elastic rod are commonly suppressed by forming half the sum of measured surface strains at diametrically opposite positions. A simple method is presented which gives a useful estimation of the bending suppression (the ratio of the bending strain to the absolute value of the evaluated axial strain when a rod is subject to bending only) from (i) optically measured mis-positioning, and (ii) estimated differences between the gauge constants for the two strain gauges. Good agreement is obtained with results obtained from strain measurements on a rod loaded in bending.
TL;DR: In this paper, the effects of geometric non-linear, modal interactions on the resonant response of spherical shell caps have been investigated in both axisymmetric and non-axisymetric modes.
Abstract: Fabrication and testing of vibrations in small-scale, electroplated nickel, spherical shell caps which are clamped on their open boundaries, are briefly described. Comparisons with theoretical predictions show that with low levels of excitation energy, for which displacements in the resonant response are considerably less than the shell thickness, classical thin shell theory provides a close description of observed resonance in both axisymmetric and non-axisymmetric modes. For larger excitation energies, for which resonant displacements are of the same order as the shell thickness, tests are reported to show the possible need to include in analysis the effects of geometric non-linear, modal interactions.
TL;DR: In this article, a new incremental procedure is proposed, that widens the scope of Marcal's stiffness method; it is notably applicable to non axisymmetrically heated tubes encountered in solar superheaters or in more conventional boilers.
Abstract: A new incremental procedure is proposed, that widens the scope of Marcal's stiffness method; it is notably applicable to non axisymmetrically heated tubes encountered in solar superheaters or in more conventional boilers.