Sökning: "viscoelastic measurements"

Visar resultat 1 - 5 av 58 avhandlingar innehållade orden viscoelastic measurements.

  1. 1. Identification of viscoelastic materials and continuous-time stochastic systems

    Författare :Magnus Mossberg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; identification; viscoelastic; continuous-time; Signal processing; Signalbehandling; Signal Processing; Signalbehandling;

    Sammanfattning : Two system identification problems, identification of viscoelastic material properties and identification of continuous-time stochastic systems, are considered in the thesis. The viscoelastic material properties are characterised by the frequency-dependent complex modulus. LÄS MER

  3. 2. Estimation of state and identification of complex modulus based on measurements om a bar traversed by waves

    Författare :Lars Hillström; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Wave; extensional; flexural; bar; rod; beam; elastic; viscoelastic; complex modulus; non-parametric; parametric; standard deviation; Materialvetenskap; Materials science; Teknisk materialvetenskap; Solid Mechanics; hållfasthetslära;

    Sammanfattning : Estimation of state and identification of complex modulus based on measurements on non-uniform rods and beams have been studied theoretically and experimentally. Two principal cases were studied. In the first case, the material properties are fully known and the state at a section is to be estimated. LÄS MER

  4. 3. Mechanistic-Empirical Modelling of Flexible Pavement Performance : Verifications Using APT Measurements

    Författare :Abubeker W. Ahmed; Sigurdur Erlingsson; Hervè Di Benedetto; Statens väg- och transportforskningsinstitut; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Performance; Deformation; Model not math ; Rutting wheel ; Viscoelasticity; Elasticity; Axle load; Flexible pavement; Laboratory not an organization ; Test; Thesis; Heavy vehicle simulator; Wheel tracking test; 32 Road: Pavement design; 32 Road: Pavement design; Transportvetenskap; Civil and Architectural Engineering;

    Sammanfattning : Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing  the   time consuming parts of the MLET processes. LÄS MER

  5. 4. Rheology and Microstructure of Mixed Biopolymer Gels

    Författare :Leif Lundin; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carrageenan; microstructure; rheology; xanthan; PCA; polysaccharide mixture; locust bean gum; transmission electron microscopy TEM ; multivariate analysis; viscoelastic measurements; PLS;

    Sammanfattning : The viscoelastic behaviour of biopolymer mixtures showing synergism was investigated under different physicochemical conditions using small deformation oscillatory measurements. In addition, the rheological properties of binary polysaccharide mixtures were related to the microstructure as observed using transmission electron microscopy. LÄS MER

  7. 5. Determination of viscoelastic material properties and impact force from measurements on impacted bodies

    Författare :Sven Ödeen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : Methods are presented for identification of linear and nonlinear viscoelastic materials and for prediction of impact force on the basis of measurements made on impacted bodies. The complex modulus is identified from measured end-point accelerations of an impacted rod specimen, and in-situ from measured strains at three sections of a rod-like member of an impacted structure. LÄS MER