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An alternative potential method for mixed steady state elastic oscillation problems
  • David Natroshvili,
  • Maia Mrevlishvili,
  • Zurab Tediashvili
David Natroshvili
Georgian Technical University

Corresponding Author:natrosh@hotmail.com

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Maia Mrevlishvili
Ilia State University
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Zurab Tediashvili
Georgian Technical University
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Abstract

We consider an alternative approach to investigate three-dimensional exterior mixed boundary value problems (BVP) for the steady state oscillation equations of the elasticity theory for isotropic bodies. The unbounded domain occupied by an elastic body, Ω − ⊂ R 3 , has a compact boundary surface S = ∂ Ω − , which is divided into two disjoint parts, the Dirichlet part S D and the Neumann part S N , where the displacement vector (the Dirichlet type condition) and the stress vector (the Neumann type condition) are prescribed respectively. Our new approach is based on the classical potential method and has several essential advantages compared with the existing approaches. We look for a solution to the mixed boundary value problem in the form of a linear combination of the single layer and double layer potentials with densities supported on the Dirichlet and Neumann parts of the boundary respectively. This approach reduces the mixed BVP under consideration to a system of boundary integral equations, which contain neither extensions of the Dirichlet or Neumann data nor the Steklov-Poincaré type operator involving the inverse of a special boundary integral operator, which is not available explicitly for arbitrary boundary surface. Moreover, the right-hand sides of the resulting boundary integral equations system are vector-functions coinciding with the given Dirichlet and Neumann data of the problem in question. We show that the corresponding matrix integral operator is bounded and coercive in the appropriate L 2 -based Bessel potential spaces. Consequently, the operator is invertible, which implies unconditional unique solvability of the mixed BVP in the class of vector-functions belonging to the Sobolev space [ W 2 , loc 1 ( Ω − ) ] 3 and satisfying the Sommerfeld-Kupradze radiation conditions at infinity. We also show that the obtained matrix boundary integral operator is invertible in the L p -based Besov spaces and prove that under appropriate boundary data a solution to the mixed BVP possesses C α -Hölder continuity property in the closed domain Ω − ‾ with α = 1 2 − ε , where ε>0 is an arbitrarily small number.
01 Oct 2023Submitted to Mathematical Methods in the Applied Sciences
03 Oct 2023Submission Checks Completed
03 Oct 2023Assigned to Editor
21 Oct 2023Review(s) Completed, Editorial Evaluation Pending
22 Oct 2023Reviewer(s) Assigned
25 Jan 20241st Revision Received
29 Jan 2024Submission Checks Completed
29 Jan 2024Assigned to Editor
29 Jan 2024Review(s) Completed, Editorial Evaluation Pending