Sökning: "elastic vibrations"

Visar resultat 21 - 25 av 43 avhandlingar innehållade orden elastic vibrations.

1. 21. Rock fragmentation by indentation and disc cutting : some theoretical and experimental studies

   Författare :Per-Arne Lindqvist; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mining and Rock Engineering; Gruv- och Berganläggningsteknik;

   Sammanfattning : The main objective of the thesis is to increase the understanding of failure mechanisms of rock drilling and rock cutting methods in general, and rock boring by disc cutters in particular. The thesis consists of five separate papers. Paper A presents the theoretical elastic stress field of indexed indenters and some laboratory observations. LÄS MER

3. 22. Models for analysis of young cast and sprayed concrete subjected to impact-type loads

   Författare :Lamis Ahmed; Anders Ansell; Richard Malm; Lennart Elfgren; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Young concrete · Shotcrete · Rock · Impact-type vibration · Finite element method · Fracture mechanics model · Crack width;

   Sammanfattning : The strive for a time-efficient construction process naturally put focus on the possibility of reducing the time of waiting between stages of construction, thereby minimizing the construction cost. If recently placed concrete, cast or sprayed, is exposed to impact vibrations at an early age while still in the process of hardening, damage that threatens the function of the hard concrete may occur. LÄS MER

4. 23. Nanomechanical Phenomena in Low-Dimensional Structures

   Författare :Anton Vikström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; superconductivity; acoustic sensors; heat flow; NEMS; surface acoustic waves; solitons; viscoelasticity; electronic edge states;

   Sammanfattning : This is a compilation thesis which investigates various mechanical phenomena in different low-dimensional nanoscale systems. In the first part, we consider a purely mechanical phenomenon: the sensitivity of the dispersion of a Love-type surface acoustic wave (SAW) to geometry and material parameters. LÄS MER

5. 24. Theoretical Description of the Electron-Lattice Interaction in Molecular and Magnetic Crystals

   Författare :Elham Mozafari; Igor A. Abrikosov; Sven Stafström; George Malcolm Stocks; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular crystals; Charge transport; Polaron; Magnetic materials; Paramagnetic state; Molecular dynamics;

   Sammanfattning : Electron-lattice interactions are often considered not to play a major role in material's properties as they are assumed to be small, the second-order effects. However, this study shows the importance of taking these effects into account in the simulations. LÄS MER

7. 25. Advanced measurement and modelling methods for noise source analysis

   Författare :Matti Rantatalo; Mats Åbom; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk akustik; Engineering Acoustics;

   Sammanfattning : In daily life sound is a vital dimension for the perception of the world around us but can in some cases be considered as annoying, irritating, or even harmful. In these cases the sound is labelled as noise and can be addressed in two ways, either by insulating the noise problem from the receiver (person) or by altering the source. LÄS MER