Toshiro Miyoshi

3D-BEM Analysis of Surface Cracks by Supercomputer

SUMMARY The authors have developed a three dimensional boundary element code, BEM3D, for elastic analysis. BEM3D runs on a supercomputer HITAC S-810/20. The algorithm is specially designed to make use of vector processing unit effectively. The code has been applied to the analysis the stress intensity factors of part-through and through wall cracks and pre and post penetration behavior of a surface crack has been discussed.

Finite element elastic-plastic analysis of growth and penetration of a surface crack

Abstract In the present paper the authors have carried out a series of elastic-plastic analyses for circumferentially cracked pipes loaded in four-point bending. They have obtained load-displacement and the J- displacement curves and the crack opening area for cracks with various configurations. Based upon these curves, an engineering approach has been applied to estimate the stable growth and instability of a surface crack. The Battelle round robin on the crack growth has been estimated well by this analysis.

Finite Element Analysis of Surface Cracks by the Supercomputer

A three dimensional finite element code, FEM3D, for a supercomputer has been developed to analyze the elastic-plastic problems of three dimensional surface cracks. In FEM3D, 20 and 15 noded isoparametric solid elements are utilized and the solver of the simultaneous linear equations is the skyline method.

Elastic-plastic Buckling of the Top End Closure of Cylindrical LNG Storage Tanks under Internal Pressure.

In the top end closure of cylindrical storage tanks for refrigerated liquefied natural gases (LNG)subjected to internal pressure, one failure mode is bifurcation buckling. The top end closure is torispherical, and buckling may occur elastic-plastically. This paper describes the buckling characteristic and the buckling pressure of a top end closure of LNG tanks, which is designed according to the current design code, API Standard 620. The axisymmetric shell finite-element method considering both geometrical and material nonlinearity in the prebuckling state is carried out. Results show that the current design code estimates the buckling pressure fairly conservatively.

FINITE ELEMENT ANALYSIS ON INITIAL AND SUBSEQUENT YIELD SURFACES OF BCC POLYCRYSTALLINE AGGREGATES

ABSTRACT At first the elastic-plastic constitutive equations for BCC single crystals have been formulated. It was assumed that plastic deformation occurred by slip only. The polycrystalline aggregate was modeled by the assembly of the finite elements each of which represented a crystal grain with a prescribed orientation. The rolling textures have been simulated and it has been found that each texture has the specific initial and subsequent yield surfaces. Further, the relation between the texture and the Rankford value has been studied. It is found that the proposed method is effective to study about the effect of microscopic mechanism of plasticity on macroscopic deformation.

Development of a seismic design system for coaxial cylindrical oil storage tanks.

The compartment tank has attracted much attention in recent years because various kinds of oil can be stored simultaneously in one tank. The coaxial cylindrical tank, which is one type of compartment tank, has been studied energetically because of its simple shape. In the seismic design of oil storage tanks, the analysis of vibration coupled with fluid motions is required by the Fire Service Law. This paper describes the development of a seismic design system for coaxial cylindrical tanks using a 16-bit personal computer. The purpose of the development is to design the tank efficiently, and to reduce the number of man-hours required for the design.