Showing papers in "International Journal of Mechanical Sciences in 1968"

TL;DR: In this paper, a finite element approach is proposed for the solution of the continuum elastic-plastic problems by means of a plastic stress-strain matrix which is derivable by inverting the Prandtl-Reuss equations in plasticity theory.

TL;DR: In this article, a completely general method of numerical visco-elastic stress analysis with constant or temperature variable properties is developed. But the method is checked against some known solutions.

TL;DR: In this article, the authors investigated the reasons for local minima in constrained optimization problems, and suggested methods leading to the global minimum, which can not be improved by iterative and gradient methods.

TL;DR: In this paper, an approximate analysis of the viscous deformation of a thin circular diaphragm clamped at the periphery and subjected to one-sided hydrostatic pressure is presented.

TL;DR: In this article, the problem of elastic strip passing between two rollers is considered by means of a numerical method, and the results provide details of the contact stresses, the indentation of the strip by the rollers, the contact width, and speed at which the strip passes through the nip in relation to the rotational speed of the roller.

TL;DR: In this paper, the stress-strain curves of various sheet metals are determined in uniaxial and balanced baoxial tension, and it is concluded that the Hill's anisotropic theory is reasonably satisfactory for materials whose anisotropy is described with r > 1, with certain anomalies for materials with r.

TL;DR: In this paper, a mean dynamic yield strength for steel and copper was derived from strain measurements on the "mushroomed" ends of flat-ended projectiles, after impact on a flat, nominally rigid anvil.

TL;DR: In this paper, the authors derived stiffness matrices for the buckling or vibration analysis of any structure consisting of a series of long, thin, flat plates rigidly connected together at their longitudinal edges.

TL;DR: In this paper, the results of a complete analysis of the deep drawing of a cylindrical cup, including the drawing and the stretch-forming parts, are presented and a correlation between the theoretical and experimental results is obtained.

TL;DR: Experiments were made in which lead rings were rolled on a model two-high mill, and the roll torque, roll force, diametral strain and diametric strain rates were measured for different reductions and peripheral velocity ratios as discussed by the authors.

TL;DR: In this article, the reference stress concept is used to predict deformations in analogous non-creep problems and gives good agreement with experimental results for beams in bending. But the reference stresses given should allow reasonable estimates of creep deformations to be made when elastic effects are present and stress redistribution occurs, and when creep laws other than the n-power law apply.

TL;DR: In this paper, a general method of studying the deflexion of variable-thickness elastic plates using the Dynamic Relaxation method is described, where non-linear terms arising in the equations to the large deflexions of plates can be included directly by the iterative finite difference technique on which the dynamic relaxation method is based.

TL;DR: In this article, experiments to assess the degree of anisotropy in titanium and zinc sheets are described Measurements of together with the mathematical theory of plasticity are used to predict the plastic flow behaviour of a circular diaphragm Correlation between experimental results and theory is not wholly satisfactory and the reasons for this are investigated.

TL;DR: In this paper, the exact solution and some approximate solutions for the free vibrations of uniform rectangular curved panels with simply supported edges are given Exact solutions are not available for all boundary conditions and a general energy method, in which the mid surface displacements are represented by truncated double-power series in the mid-surface co-ordinates of the panel, is outlined.

TL;DR: In this paper, a method for selecting velocity fields which are admissible for the incompressible material is presented for extrusion processes through three basic types of axisymmetric curved dies: cosine, elliptic and hyperbolic.

TL;DR: In this paper, a model experimental single mandrel ring-rolling mill was designed and constructed to roll lead rings to a maximum overall percentage reduction of 50% in force and torque measurements.

TL;DR: In this article, a numerical method for the boreexpanding test of sheet metals is applied to the strain-hardening characteristics of the material and the stress and strain distributions and the maximum load in the relevant test have been calculated by use of the incremental theory of plasticity.

TL;DR: In this article, the conditions for stable operation of band-saw blades, belt drives, and belt drives were determined and theoretical conclusions were verified experimentally, and the parametric excitation is due to periodic variations in the band tension resulting from wheel eccentricity.

TL;DR: In this article, the dynamic compression of circular cylinders of different types of steel at elevated temperatures and at high strain-rates were investigated using an experimental drop hammer instrumented with an accelerometer and capacitive-type transducer.

TL;DR: In this article, the effect of initial imperfections on the postbuckling behavior of a class of elastic structural systems whose ideal behavior has been established previously is discussed, and changes in buckle pattern may be attributable to the presence of such imperfections.

TL;DR: In this article, it was shown that the use of a mean yield stress underestimates the working loads (or stresses) needed to draw metal through conical dies as compared to those loads predicted by more "exact" analyses.

TL;DR: In this article, the instability of an edge-loaded, constant velocity, axially moving band is analyzed and a numerical procedure for critical edge-load determination is presented, which is sufficiently accurate for applications in the relatively large stiffness to tension ratio range E∗ > 0·1.

TL;DR: In this article, a method of developing a stiffness matrix for a rectangular, moderately thick plate element is presented, thus enabling some of the advantages of finite element treatments (variable plate thickness, anisotropy, etc.) to be applied to certain problems in which thin plate theory might be considered inadequate.

TL;DR: A theoretical analysis of the process of tube expanding by electromagnetic forces indicates that time-varying tube inductance, circuit resistance and the irreversible plastic work done on the tube are significant parameters of the performance of the electromagnetic forming machine.

TL;DR: In this paper, a model for the effects of mild anisotropy on the relationship between the stress components and the plastic strain increments suggests that the Levy-Mises equations will give serious errors in estimates of the surface stress components in compression tests.

TL;DR: In this paper, an analysis of instability in tension tests is presented, where the flow stress is a unique function of strain, strain-rate and temperature, and the critical impact velocity is discussed and some theoretical predictions are compared with experimental results.

TL;DR: In this article, it is shown that if a ring is indented across its thickness a plastic zone is formed at the point of indentation, and if the indentation force is sufficiently large, a plastic hinge is formed in the ring, diametrically opposite the point in indentation.

TL;DR: In this article, the local buckling of a polygonal tube, with N identical walls, due to combined uniform longitudinal compression and torsion was studied, and interaction curves were calculated for the cases of N = 3 and N = 4.

TL;DR: In this paper, the non-linear bending equation for a cantilever beam with a perpendicular load applied at the tip, undergoing large deflections, is solved by computer methods for both rectangular and round cross-sections, for varying degrees of taper and are compared with values obtained by laboratory tests.

TL;DR: In this article, the authors derived approximate equations to account for the compressive engineering strain-time and dynamic force-time characteristics for the fast compression of prismatic blocks of strain-hardening, strain-rate-sensitive material using a drop hammer.