Sökning: "Micro-structure"

Visar resultat 1 - 5 av 34 avhandlingar innehållade ordet Micro-structure.

1. 1. Micro-Structure Modelling of Acoustics of Open Porous Material

   Författare :Eva Lundberg; Peter Göransson; Per Wennhage; Ulf Orrenius; Camille Perrot; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; acoustics; porous material; flow resistivity; micro-structure; anisotropic; foam; strut; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : Transportation is a large and growing part of the world’s energy consumption. This drives a need for reduced weight of rail vehicles, just as it does for road vehicles. In spite of weight reductions, the vehicle still has to provide the same level of acoustic comfort for the passengers. LÄS MER

3. 2. Time dependent material properties of shotcrete for hard rock tunnelling

   Författare :Lars Elof Bryne; Anders Ansell; Wolfgang Kusterle; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shotcrete; rock; granite; bond strength; compressive strength; pullout testing; failure modes; interfacial transition zone; micro structure; ettringite; set accelerator; shrinkage; drains; glass fibres; laboratory testing; tunnels tunnelling;

   Sammanfattning : In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. LÄS MER

4. 3. Ageing of Asphalt Mixtures : Micro-scale and mixture morphology investigation

   Författare :Prabir Kumar Das; Björn Birgisson; Nicole Kringos; Andreas Loizos; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ageing; Aggregate packing; Atomic force microscopy; Asphalt mixture; Bitumen; Diffusion; Finite element analysis; Gradation; Micro-structure; Mixture morphology; Oxidative ageing; Surface ageing;

   Sammanfattning : There are many variables that affect the viscoelastic properties of asphalt mixtures with time, among which age hardening may be considered one of the important ones. Age hardening of asphalt mixtures is an irreversible process, which contributes to a reduction of the durability of pavements and eventually increases the maintenance cost. LÄS MER

5. 4. Aspects of creep-fatigue in gas turbine hot parts

   Författare :Magnus Hasselqvist; Gunnar Härkegård; Linköpings universitet; []
   Nyckelord :creep; fatigue; TMF; gas turbine; modelling; life assessment; ageing; micro-structure; solute drag; back stress; Haynes 230; IN792;

   Sammanfattning : The goal is reliable creep-fatigue lifing methodology for industrial gas turbines.A literature study on high temperature materials used in gas turbines reveals that:• Most testing/modelling work has focused on characterisation and modelling of material response in isothermal standard tests, i.e. creep, tensile and LCF tests. LÄS MER

7. 5. Micro-structural based acoustic modelling of anisotropic open cell materials

   Författare :Eva Lundberg; Huina Mao; Bradley Semeniuk; Peter Göransson; Mathieu Gaborit; Romain Rumpler; Peter Göransson; Elke Deckers; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sound absorption; vehicle; anisotropic; foam; micro-structure; resource efficient; transfer matrix method; ljudabsorption; anisotrop; skum; mikrostruktur; TMM; fordon; resurseffektiv; Farkostteknik; Vehicle and Maritime Engineering;

   Sammanfattning : A method for the calculation of the acoustic performance of open-cell foammaterials is discussed. From a known micro-structural geometry and theconstituent material, the relevant acoustic properties are computed using apreviously published analytical method for the calculation of the dynamicdrag impedance and a previously published method for the calculation of theelastic moduli. LÄS MER