Sökning: "finita elementmetoden"

Visar resultat 21 - 24 av 24 avhandlingar innehållade orden finita elementmetoden.

  1. 21. Properties of Volume Bragg Gratings and Nonlinear Crystals for Laser Engineering

    Författare :Staffan Tjörnhammar; Fredrik Laurell; Valdas Pasiskevicius; Takunori Taira; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; volume Bragg grating; VBG; thermal effects; nonlinear optics; KTiOPO4; quasi-phase matching; photochromic damage; grey-tracking; color centers; blue-light induced infrared absorption; BLIIRA; Physics; Fysik;

    Sammanfattning : This thesis focuses on two topics: thermal limitations of volume Bragg gratings (VBGs) employed as laser-cavity mirrors and formation of color centers in KTiOPO4 and its isomorphs.To explore the mechanisms of the thermal limitations of VBGs in high power lasers, I designed and constructed a diode-pumped, solid‑state laser with a VBG as cavity mirror that had a significantly higher absorption than what is typical. LÄS MER

  3. 22. Numerical models for degradation of concrete in hydraulic structures due to long-term contact with water

    Författare :Daniel Eriksson; Anders Ansell; Richard Malm; Erik Nordström; Katja Fridh; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; degradation; deterioration mechanisms; hydraulic structures; air-entrained concrete; multiphase model; long-term moisture conditions; pore size distribution; freezing; partially saturated; finite element method; Civil and Architectural Engineering; Byggvetenskap;

    Sammanfattning : The durability of concrete is of major concern in all types of concrete structures where the combined effect of exposure conditions and the type and quality of the concrete material usually determines the rate of degradation. Furthermore, there are synergy effects between different deterioration mechanisms, which means that the combined rate of degradation is higher than the sum of the individual rates of each mechanism. LÄS MER

  4. 23. Patch loading resistance of plated girders : ultimate and serviceability limit state

    Författare :Jonas Gozzi; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel Structures; Stålbyggnad;

    Sammanfattning : Patch loading or partial edge loading of steel girder webs is a load case where a concentrated force is introduced perpendicular to the flange of a girder. This usually induces a local failure of the girder web in the vicinity of the loaded flange. LÄS MER

  5. 24. Impact of paperboard deformation and damage mechanisms on packaging performance

    Författare :Gustav Marin; Sören Östlund; Mikael Nygårds; Tomasz Garbowski; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Solid Mechanics; Hållfasthetslära;

    Sammanfattning : Paper-based materials, such as paperboard, are commonly used as packaging materials. In addition to the fact that paper is renewable, there are also many other benefits of paperboard. LÄS MER