Numerical approach for ECT by using boundary element method with Laplace transform

1997 ◽  
Vol 33 (2) ◽  
pp. 2135-2138 ◽  
Author(s):  
M. Enokizono ◽  
T. Todaka ◽  
K. Shibao
Keyword(s):  
Boundary Element Method ◽  
Laplace Transform ◽  
Boundary Element ◽  
Numerical Approach ◽  
Element Method

An Effective Numerical Approach for Multiple Void-Crack Interaction

2005 ◽  
Vol 73 (4) ◽  
pp. 525-535 ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Elastic Plate ◽  
Homogeneous Problem ◽  
Crack Problem ◽  
General System ◽  
Numerical Approach ◽  
Displacement Discontinuity ◽  
Crack Problems ◽  
Element Method

This paper presents a numerical approach to modeling a general system containing multiple interacting cracks and voids in an infinite elastic plate under remote uniform stresses. By extending Bueckner’s principle suited for a crack to a general system containing multiple interacting cracks and voids, the original problem is divided into a homogeneous problem (the one without cracks and voids) subjected to remote loads and a multiple void-crack problem in an unloaded body with applied tractions on the surfaces of cracks and voids. Thus the results in terms of the stress intensity factors (SIFs) can be obtained by considering the latter problem, which is analyzed easily by means of the displacement discontinuity method with crack-tip elements (a boundary element method) proposed recently by the author. Test examples are included to illustrate that the numerical approach is very simple and effective for analyzing multiple crack/void problems in an infinite elastic plate. Specifically, the numerical approach is used to study the microdefect-finite main crack linear elastic interaction. In addition, complex crack problems in infinite/finite plate are examined to test further the accuracy and robustness of the boundary element method.

An Energy Diffusion Model for Interior Acoustics With Structural Coupling Using the Boundary Element Method

2012 ◽  
Author(s):  
Joseph M. Corcoran ◽  
Ricardo A. Burdisso
Keyword(s):  
Boundary Element Method ◽  
Diffusion Equation ◽  
Laplace Transform ◽  
Diffusion Process ◽  
Boundary Element ◽  
Diffusion Model ◽  
Acoustic Energy ◽  
Room Acoustics ◽  
Energy Diffusion ◽  
Element Method

Recently, a new model for the propagation of sound in interior volumes known as the acoustic diffusion equation has been explored as an alternative method for acoustic predictions and analysis. The model uses statistical methods standard in high frequency room acoustics to compute a spatial distribution of acoustic energy over time as a diffusion process. For volumes coupled through a structural partition, the energy consumed by structural vibration and acoustic energy transmitted between volumes has been incorporated through a simple acoustic transmission coefficient. In this paper, a Boundary Element Method (BEM) solution to the simple diffusion model is developed. The integral form of the 3D acoustic diffusion equation for coupled volumes is derived using the Laplace transform and Green’s Second Identity. The solution using the BEM is developed as well as an efficient Laplace transform inversion scheme to obtain both steady state and transient interior acoustic energy. In addition, a fully coupled model where both structural and acoustic energy are computed as a diffusion process is proposed. A simple volume configuration is examined as the diffusion models are analyzed and compared to conventional room acoustics analysis methods. Advantages of the energy diffusion methods over conventional methods, such as computation of energy distributions and accurate transmission from one volume to another, are revealed as the comparisons are made.

scholarly journals Numerical study of single bubble mobility in triangular and deltoid microchannels using the boundary element method

2021 ◽  
Vol 2057 (1) ◽  
pp. 012042
Author(s):  
A Z Bulatova ◽  
O A Solnyshkina ◽  
N B Fatkullina
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Complex Geometry ◽  
Numerical Study ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Variable Pressure ◽  
Bubbly Liquid ◽  
Element Method

Abstract The study of bubbly liquid dynamics in microchannels of unconventional shapes is of great importance for different fields of science and industry. This work investigates the dynamics of the incompressible single bubbles in the slow periodic flow of viscous liquid in a triangular channel with a variable pressure gradient. The numerical approach used in this research is based on the boundary element method (BEM). This method is widely used for solving three-dimensional problems and problems in areas with complex geometry. The influence of the bubble’s initial position relative to the channel centerline on the bubble deformation, the relative velocity of the bubble, and its center of mass displacement in the channel are considered.

Direct numerical simulation of three-dimensional dynamics of compressible bubbles in acoustic field using boundary element method

2014 ◽  
Vol 10 ◽  
pp. 59-65
Author(s):  
Yu.A. Itkulova ◽  
O.A. Abramova ◽  
N.A. Gumerov ◽  
I.Sh. Akhatov
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Bubble Dynamics ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Numerical Approach ◽  
Low Reynolds Numbers ◽  
Dimensional Simulation ◽  
Element Method

In the present work the dynamics of bubbles containing compressible gas is studied in the presence of an acoustic field at low Reynolds numbers. The numerical approach is based on the boundary element method (BEM), which is effective for three-dimensional simulation. The application of the standard BEM to the compressible bubble dynamics faces the problem of the degeneracy of the algebraic system. To solve this problem, additional relationships based on the Lorentz reciprocity principle are used. Test calculations of the dynamics of one and several bubbles in an acoustic field are presented.

A Study on Contact Stress Analysis in Boundary Element Method

2000 ◽  
Author(s):  
Mehmet Çelik
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Engineering Design ◽  
Contact Stress ◽  
Load Distribution ◽  
Roller Bearing ◽  
Contact Problems ◽  
Numerical Approach ◽  
Superposition Method ◽  
Element Method

Abstract A numerical approach for the solution of the contact mechanics problems has been presented using the Boundary Element Method. An automatic load distribution technique is implemented in a contacting element using isoparametric quadratic elements. This type of element is shown to be excellent in modeling regions of rapidly varying stresses in the contact areas. The superposition method is applied to interference contact problems mostly used in engineering design of the systems. The work is focused on the analysis of the loading in a roller bearing housing.

Boundary element analysis of finite domains under thermal and mechanical shock with the Lord-Shulman theory

2003 ◽  
Vol 38 (1) ◽  
pp. 53-64 ◽  
Author(s):  
P Hosseini-Tehrani ◽  
M. R Eslami
Keyword(s):  
Boundary Element Method ◽  
Laplace Transform ◽  
Boundary Element ◽  
Relaxation Times ◽  
Finite Domain ◽  
Laplace Transform Method ◽  
Transform Method ◽  
Laplace Transform Technique ◽  
The Laplace Transform ◽  
Element Method

A boundary element method based on the Laplace transform technique is developed for transient coupled thermoelasticity problems with relaxation times in a two-dimensional finite domain. The dynamic thermoelastic model of Lord and Shulman (LS) is selected to show how mechanical and thermal energy conversion takes place in a coupled field. The Laplace transform method is applied to the time domain and the resulting equations in the transformed field are discretized using the boundary element method. The nodal dimensionless temperature and displacements in the transformed domain are inverted to obtain the actual physical quantities, using the numerical inversion of the Laplace transform method. The creation and propagation of elastic and thermoelastic waves in a finite domain and their effects on each other are investigated for the first time in this paper. Different relaxation times are chosen to show briefly the events that take place in temperature, displacement and stress fields considering the LS theory. Details of the formulation and numerical implementation are presented.

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