INVESTIGATION OF THE THREE-DIMENSIONAL HELMHOLTZ EQUATION FOR A WEDGE USING THE BLOCK ELEMENT METHOD

2021 ◽  
Vol 62 (5) ◽  
pp. 717-722
Author(s):  
V. A. Babeshko ◽  
O. V. Evdokimova ◽  
O. M. Babeshko
2019 ◽  
Vol 23 (Suppl. 2) ◽  
pp. 591-597
Author(s):  
Ilya Telyatnikov

We consider a model of lithospheric structures contacting along rectilinear geological faults as a system of composite plates on an elastic foundation. A simplification of the block element method for different-sized blocks is proposed. We also describe an approach that is a modification of the block element method using the method of eigenfunctions. The method is considered on the example of a static interaction problem of extended plates on the surface of an elastic layer for a given surface load. As a result we obtain the representations of solutions describing the surface displacements. The application of the proposed approach will allow us to draw conclusions about the effect of the physical and mechanical properties of lithospheric structures and the type of fault on the nature of displacements in the geological environment which are applicable for studying the structure of faults in the upper part of the earth's crust.


Author(s):  
V.A. Babeshko ◽  
O.V. Evdokimova ◽  
O.M. Babeshko

There are several approaches aimed at simplifying complex partial differential equations or their systems involved in the formulation of boundary value problems by introducing simpler, but in a larger number of differential equations. Their solutions allow us to describe solutions to complex boundary value problems. However, to implement this approach, it is necessary to construct solutions of simplified boundary value problems for arbitrary boundary conditions in solvability spaces boundary value problem. In some cases, this can be done using the block element method. The block element method, which has a topological basis, reveals both global and local properties of solutions to boundary value problems for partial differential equations. At the same time, it can be used to study and solve more complex boundary value problems by applying relations that describe certain equations of the continuum by means of relatively simple equations, for example, Helmholtz. To do this, we need to construct solutions of the Helmholtz equations that satisfy boundary conditions that contain completely arbitrary values, rather than partial values, set at the boundary of functions. In relation to the Helmholtz equations, this is achieved using the block element method. Examples of constructing solutions to boundary value problems for Helmholtz equation for Dirichlet and Neumann problems and a comparative analysis of solutions are given in this article.


2011 ◽  
Vol 56 (6) ◽  
pp. 348-351 ◽  
Author(s):  
V. A. Babeshko ◽  
O. V. Evdokimova ◽  
O. M. Babeshko

2012 ◽  
Vol 15 (3-4) ◽  
pp. 206-213 ◽  
Author(s):  
Vladimir A. Babeshko ◽  
O. M. Babeshko ◽  
O. V. Evdokimova

Author(s):  
Sebastian Grabmaier ◽  
Matthias Jüttner ◽  
Wolfgang Rucker

Purpose Considering the vector Helmholtz equation in three dimensions, this paper aims to present a novel approach for coupling the finite element method and a boundary integral formulation. It is demonstrated that the method is well-suited for many realistic three-dimensional problems in high-frequency engineering. Design/methodology/approach The formulation is based on partial solutions fulfilling the global boundary conditions and the iterative interaction between them. In comparison to other coupling formulation, this approach avoids the typical singularity in the integral kernels. The approach applies ideas from domain decomposition techniques and is implemented for a parallel calculation. Findings Using confirming elements for the trace space and default techniques to realize the infinite domain, no additional loss in accuracy is introduced compared to a monolithic finite element method approach. Furthermore, the degree of coupling between the finite element method and the integral formulation is reduced. The accuracy and convergence rate are demonstrated on a three-dimensional antenna model. Research limitations/implications This approach introduces additional degrees of freedom compared to the classical coupling approach. The benefit is a noticeable reduction in the number of iterations when the arising linear equation systems are solved separately. Practical implications This paper focuses on multiple heterogeneous objects surrounded by a homogeneous medium. Hence, the method is suited for a wide range of applications. Originality/value The novelty of the paper is the proposed formulation for the coupling of both methods.


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