Application of the Laplace transform dual reciprocity boundary element method in the modelling of laser heat treatments

2005 ◽  
Vol 29 (2) ◽  
pp. 126-135 ◽  
Author(s):  
J.M. Amado ◽  
M.J. Tobar ◽  
A. Ramil ◽  
A. Yáñez
2003 ◽  
Vol 38 (1) ◽  
pp. 53-64 ◽  
Author(s):  
P Hosseini-Tehrani ◽  
M. R Eslami

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.


Author(s):  
Joseph M. Corcoran ◽  
Ricardo A. Burdisso

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.


2014 ◽  
Vol 1040 ◽  
pp. 633-637 ◽  
Author(s):  
Leonid A. Igumnov ◽  
Ivan Markov ◽  
Yan Yu. Rataushko

The numerical modeling problem is solved using a direct formulation of the boundary element method. The integral Laplace transform is used, as well as time-step methods of its numerical inversion. Matrices of fundamental and singular solutions are computed with the help of a combined direct-interpolation approach. The computational results obtained are compared with the results of other authors.


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