Search for dissertations about: "time-integration"

Showing result 1 - 5 of 35 swedish dissertations containing the word time-integration.

  2. 1. Adaptive time-integration for goal-oriented and coupled problems

    Author : Peter Meisrimel; Numerisk analys; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; time-adaptivity; goal-oriented problems; error estimation; coupled problems; waveform relaxation; asynchronous methods; conjugate heat transfer;

    Abstract : We consider efficient methods for the partitioned time-integration of multiphysics problems, which commonly exhibit a multiscale behavior, requiring independent time-grids. Examples are fluid structure interaction in e.g., the simulation of blood-flow or cooling of rocket engines, or ocean-atmosphere-vegetation interaction. READ MORE

  4. 2. Fractional Calculus and Linear Viscoelasticity in Structural Dynamics

    Author : Mikael Enelund; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; linear viscoelasticity; convolution integrals; anisotropy; structural modeling; finite elements; material damping; time integration; internal variables; relaxation; fractional calculus; creep; Mittag-Leffler functions;

    Abstract : The use of linear viscoelasticity together with fractional calculus in time-domain structural modeling is studied. Both constitutive and structural aspects are investigated. READ MORE

  5. 3. Modelling Stiffness and Damping by Use of Fractional Calculus with Application to Railpads

    Author : Åsa Fenander; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; stiffness; initial conditions; modal synthesis; time integration; measurements; fractional calculus; railway tracks; fractional integrals; damping; railpads; structural dynamics; fractional derivatives; mathematical models;

    Abstract : When studying the dynamic behaviour of a structure, e g a railway track, it is important for the analyst to model both stiffness and damping accurately. Mathematical models including fractional derivatives have been found to work well for many materials. Such models are linear and causal. READ MORE

  6. 4. Structural Reliability and Identification with Stochastic Simulation - Application to Railway Mechanics

    Author : Sadegh Rahrovani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; model reduction; time-integration; finite element model; sleeper-ballast load characterization; stochastic simulation; Bayesian system identification;

    Abstract : System identification of structures based on measured response data can play a key role in improving reliability based structural designs. However, the experimental limitations of in situ tests and uncertainties of required model complexity together with the inverse nature of system identification give rise to a number of challenging issues. READ MORE

  7. 5. An Integration-Reduction Scheme for Simulation of Large Systems with Local Nonlinearity and Uncertainty - Application to moving load problems in railway mechanics

    Author : Sadegh Rahrovani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Monte-Carlo simulations; time-integration; moving load problems; reliability analysis; exponential integrator; symplectic integrator; modal dominancy analysis;

    Abstract : The focus of this research is mainly on computational efficiency, as future work is planned for reliability analysis that will be combined with design optimisation. Both these fields are known to be notoriously computationally demanding. READ MORE