Hisao Hasegawa

A Boussinesq's Problem of an Elastic Half Space with an Elastic Spherical Inclusion

The problem of determing of stresses and displacements of an elastic half space subjected to a concentrated force acting at a point of the plane surface is called Boussinesqs problem. This paper deals with Boussinesqs problems of an elastic half space with an elastic spherical inclusion. We use a body force distribution method for the stress concentration problem. For this purpose, we apply the Greens functions for axisymmetric body force problems of an elastic half space and the fundamental solution for axisymmetric body force problems of elasticity. The problem is formulated by an integral equation with unknown functions corresponding to the intensities of distributed body forces. Stress distributions around the inclusion are shown by numerical calculations and influences of elastic moduli on the stresses are also investigated.

Green's functions for torsional body force problems of a dissimilar elastic thick plate.

Greens functions are shown for axisymmetric torsional body force problems of a dissimilar elastic thick plate. Greens functions are defined as solutions to the problem of a dissimilar elastic thick plate subjected to a torsional body force acting on a circle in the interior of the thick plate. As a special case for the Greens functions shown, we can obtain Greens functions for torsional body force problems of an elastic half-space, an elastic thick plate, a dissimilar elastic solid, an elastic layer on an elastic half-space, among others. A general method of solution is presented for torsional body force problems of a dissimilar elastic thick plate. The Greens functions shown here are obtained by applying the general method of solution. As an example of the application of Greens functions, we consider the torsion of a hemispherical rigid body embedded in the dissimilar thick plate. Numerical results for the problem are shown.

Stress concentration of a circular solid cylinder with semicircular notches under tension. Stress mitigations by additional notches.

This paper deals with the stress concentration problem of a circular solid cylinder with a central notch and two supplemental notches under tension. Stress mitigations due to the interference effects of stress concentration are investigated. We consider the influences of the distances between a central notch and two supplemental notches and the radii of the semicircular notches on the mitigations of stress concentration. The principle of the method of solution makes use of distributing body forces in the interior of a solid cylinder in order to satisfy the boundary conditions of the notched surfaces, which are imagined in the solid cylinder with no notch. For this purpose, we apply Greens functions for body force problems of an infinite solid cylinder. Numerical results are shown for stress concentration factors of the problem.

Tension of a Circular Solid Cylinder with Two Semicircular Grooves : Interference Effects of Stress Concentrations due to Two Notches

This paper is concerned with the stress concentration problem of an elastic solid cylinder with two semicircular grooves under tension. The principal results are as follows: Interference effects of stress concentration due to two notches (a phenomenon leading to α2/α1 0.5, there are cases of α2/α1 > 1.0, as was suggested by Nisitani et al. for an infinite number of periodic notches. The interference effects of two notches are smaller than those of periodic infinite notches and larger in tension than in torsion. The method of solution used here is an application of Greens functions for axisymmetric body force problems of a solid cylinder.