Adaptive solid wave propagation—influences of boundary conditions in high-speed train applications

• Published in: Computer methods in applied mechanics and engineering Vol. 195; no. 4; pp. 236 - 250
• Main Authors: Ekevid, Torbjörn, Lane, Håkan, Wiberg, Nils-Erik
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-2006; Elsevier
• Subjects: Absorbing boundaries; Adaptivity; Applied sciences; Buildings. Public works; Computational techniques; Engineering mechanics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Geotechnics; Hybrid method; Maskinteknik; Mathematical methods in physics; Mechanical Engineering; Other engineering mechanics; Physics; Soil mechanics. Rocks mechanics; Solid mechanics; Structural and continuum mechanics; TECHNOLOGY; TEKNIKVETENSKAP; Teknisk mekanik; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Wave propagation; Övrig teknisk mekanik; Adaptivity; Absorbing boundaries; Wave propagation; Hybrid method; Rock mechanics; Error estimation; Refinement method; Rail vehicle; Soft soil; Density; Automatic mesh generation; Modeling; Soil mechanics; Adaptive method; Shock wave; Wave reflection; Finite element method; Variable section; Wave transmission; Time varying system; High speed train; Distributed parameter system; Mesh generation
• ISSN: 0045-7825; 1879-2138
• DOI: 10.1016/j.cma.2004.12.030

Wave propagation in solid materials is of great interest in many engineering applications. The fact that the area of interest changes with time creates a number of computational problems such as the need for a mesh density varying in space and time. This means that the mesh must be continuously updated and controlled, rendering a large demand of computer effort.
In certain applications like railway mechanics there are mobile loads. A load speed close to the natural speed in the underlying soil causes specific problems, shock waves being one of them. The transmitted waves have to leave the defined finite element domain without reflection, which imposes a need for certain modelling methods. The paper will deal with quality controlled FE-procedures for wave propagation including error estimation and mesh refinement/coarsening. As an application an important problem from railway mechanics is considered. When a high-speed train approaches an area with decreasing thickness of underlying soft soil on a stiff rock it is expected that the reflection of the wave will increase the total amplitude of the wave. We will study this problem with the procedures described above in full 3D with partly absorbing boundaries.