Sökning: "elastic wave equation"

Visar resultat 11 - 15 av 22 avhandlingar innehållade orden elastic wave equation.

1. 11. Difference methods with boundary and interface treatment for wave equations

   Författare :Kristoffer Virta; Gunilla Kreiss; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : Wave motion in acoustic and elastic media is highly influenced by the presence of outer boundaries and media interfaces. The solutions to the equations governing the wave motion at any point in the domain as a function of time can be sought either through analytical or numerical techniques. LÄS MER

3. 12. Modelling of ultrasonic scattering from a crack in a pipe

   Författare :Jacob Rubenson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-Destructive Testing; Cylindrical Geometry; Pipe; Crack; Wave propagation;

   Sammanfattning : This thesis considers elastic wave scattering in an infinitely long cylindrical pipe with an infinitely long internal axial crack. The method used in this thesis is called a hypersingular integral equation method since it starts with an integral representation and by using the Green's tensor of the pipe it can be manipulated to a hypersingular equation for the crack-opening displacement (COD). LÄS MER

4. 13. Spectra and Dynamics of Excitations in Long-Range Correlated Structures

   Författare :Lars Kroon; Rolf Riklund; Magnus Johansson; Jeroen Lamb; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quasicrystals; deterministic aperiodic superlattices; Markov chains; electronic structure and diffusion; elastic vibrations; Fraunhofer diffraction; discrete solitons; phase transitions; Condensed matter physics; Kondenserade materiens fysik;

   Sammanfattning : Vad karaktäriserar en kristall? Svaret på denna till synes enkla fråga blir kanske att det är en anordning av atomer uppradade i periodiska mönster. Så ordnade strukturer kan studeras genom att det uppträder så kallade Braggtoppar i röntgendiffraktionsmönstret. LÄS MER

5. 14. Numerical methods for wave propagation in solids containing faults and fluid-filled fractures

   Författare :Ossian O'Reilly; Jan Nordström; Per Lötstedt; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis develops numerical methods for the simulation of wave propagation in solids containing faults and fluid-filled fractures. These techniques have applications in earthquake hazard analysis, seismic imaging of reservoirs, and volcano seismology. A central component of this work is the coupling of mechanical systems. LÄS MER

7. 15. Approximations of Integral Equations for WaveScattering

   Författare :Andreas Atle; Björn Engquist; Richard Tsai; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Integral equations; Marching on in time; On surface radiation condition; Physical Optics; Numerical analysis; Numerisk analys;

   Sammanfattning : Wave scattering is the phenomenon in which a wave field interacts with physical objects. An incoming wave is scattered at the surface of the object and a scattered wave is produced. Common practical cases are acoustic, electromagnetic and elastic wave scattering. LÄS MER