Initial stress formulation for elastoplastic analysis by improved multiple-reciprocity boundary element method

Numerical Meth Engineering

2009

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SUMMARYIn general, internal cells are required to solve thermo-elastoplasticity problems by a conventional boundary element method (BEM). However, in this case, the merit of BEM, which is the easy preparation of data, is lost. A conventional multiple-reciprocity boundary element method (MRBEM) cannot be used to solve elastoplasticity problems, because the distribution of initial strain or stress cannot be determined analytically. In this study, it is shown that without the use of internal cells, two-dimensional thermoelastoplasticity problems can be solved by a triple-reciprocity BEM using a thin plate spline. Initial strain and stress formulations are adopted and the initial strain or stress distribution is interpolated using boundary integral equations. A new computer program was developed and applied to solve several problems.

Section: Interpolation Of Initial Strainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Meshless thermo‐elastoplastic analysis by triple‐reciprocity boundary element method

Numerical Meth Engineering

2009

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“…Interpolation using a polyharmonic function [7] was derived from the boundary element method for heat conduction analysis during heat generation [8]. Because a curved surface can be smoothly interpolated using the boundary geometry of the region and arbitrary internal points in the region, we have thus far applied this interpolation to computer-aided design (CAD) [9], the initial stress-speed distribution in nonlinear stress analysis [10], and the initial strain-speed distribution [11]. Digital images are usually represented in the form of a matrix that indicates the data of intensity of each pixel.…”

Section: Introductionmentioning

confidence: 99%

Image processing by interpolation using polyharmonic function and increase in processing speed

Kobayashi

Kawashima

IEEJ Transactions Elec Engng

2010

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Digital images are usually represented in the form of a matrix that indicates the data of intensity of each pixel. When the data of intensity of each pixel are considered as the data of the height in the coordinates of the pixel and the pixels are smoothly connected, the digital image can be reconstructed as a curved surface. Interpolation using a polyharmonic function can interpolate a curved surface smoothly using the boundary geometry of the region and arbitrary internal points in the region. In this study, we applied the interpolation method to image processing, and propose a method which can restore and enlarge images smoothly. The method proposed here can realize the simultaneous restoration and smooth enlargement of images, which has been difficult to achieve by conventional methods. This method is applied to the enlargement of images while restoring damaged areas or to the enlargement of an image of the face of persons who is wearing glasses while removing the glasses frame from the image, and its effectiveness is demonstrated. In addition, a method of increasing processing speed by division processing is also examined, and its validity is confirmed. 

“…Accordingly, the conventional multiple-reciprocity method is not suitable for practical steady thermal stress analyses with arbitrary internal heat generation in the domain. On the other hand, Ochiai and coworkers have proposed the improved multiple-reciprocity BEM for the steady heat conduction problem, steady thermal stress problem and elastoplasticity problem [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Using this method, a highly accurate solution may be obtained solely by using the fundamental solutions of lower order without the need for mesh data preparing. In this method, heat generation distribution is interpolated using the boundary integral equations [5][6][7][8]. Point and line heat sources are easily treated by the conventional BEM.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional steady thermal stress analysis by triple-reciprocity boundary element method

Int. J. Numer. Meth. Engng

2005

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SUMMARYThe steady thermal stress problems without heat generation can be solved easily by the boundary element method. However, for the case with arbitrary heat generation, the domain integral is necessary. In this paper, it is shown that the problems of three-dimensional steady thermal stress with heat generation can be approximately solved without the domain integral by the triple-reciprocity boundary element method. In this method, an arbitrary distribution of heat generation is interpolated by boundary integral equations. In order to solve the problem, the values of heat generation at internal points and on the boundary are used.