Sökning: "Nonlinear structure"

Visar resultat 1 - 5 av 265 avhandlingar innehållade orden Nonlinear structure.

1. 1. Regressor and Structure Selection : Uses of ANOVA in System Identification

   Författare :Ingela Lind; Lennart Ljung; Torsten Söderström; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; System identification; Regressor selection; Analysis of variance; Nonlinear systems; Structure selection; Automatic control; Reglerteknik;

   Sammanfattning : Identification of nonlinear dynamical models of a black box nature involves both structure decisions (i.e., which regressors to use and the selection of a regressor function), and the estimation of the parameters involved. LÄS MER

3. 2. Finite Element Modelling of Fluid-Structure Interaction

   Författare :Göran Sandberg; Byggnadsmekanik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Finite Element Method; Coupled problem; fluid-structure interaction; Transient; Acoustics; Caviation; Time Stepping; Symmetric; Nonlinear acoustics; Submerged structures; finite element method; Coupled problem; Fluid-structure interaction; Transient; Acoustics; Cavitation; Time Stepping; Symmetric; Nonlinear acoustics; Submerged structures;

   Sammanfattning : The dynamic interaction between non-viscid, compressible fluid and an elastic structure is studied. Finte element formulations, using the weighted residual method, are derived. Different primary variables in the fluid domain are used and different source functions are considered. LÄS MER

4. 3. Nonlinear Approaches to Periodic Signal Modeling

   Författare :Emad Abd-Elrady; Torsten Söderström; Torbjörn Wigren; Jonas Sjöberg; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cramer-Rao bounds; frequency estimation; identification; limit cycle; nonlinear systems; periodic signals; Wiener model structure; Signal processing; Signalbehandling; Signalbehandling; Signal Processing;

   Sammanfattning : Periodic signal modeling plays an important role in different fields. The unifying theme of this thesis is using nonlinear techniques to model periodic signals. The suggested techniques utilize the user pre-knowledge about the signal waveform. This gives these techniques an advantage as compared to others that do not consider such priors. LÄS MER

5. 4. Nonlinear response in engineered optical materials

   Författare :Gustav Strömqvist; Valdas Pasiskevicius; Peter Smith; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nonlinear optics; nonlinear index of refraction; double tungstates; periodic poling; KTiOPO4; quasi-phase matching; parametric down-conversion; mirrorless optical parametric oscillators;

   Sammanfattning : Material and structure engineering are increasingly employed in active optical media,in this context defined as media capable of providing laser or/and optical parametric gain. For laser materials, the main aim of the engineering is to tailor the absorption and emission cross sections in order to optimise the laser performance. LÄS MER

7. 5. Nonlinear Structural Identification Using a Multi-Harmonic  Frequency Response Functions

   Författare :Vahid Yaghoubi Nasrabadi; Thomas Abrahamsson; Andreas Linderholt; Martin Magnevall; Chalmers; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nonlinear structure; inverse problem; grey box system identification; finite element model updating; identifiability; Fisher information matrix; multi-harmonic frequency response function; Maskinteknik; Mechanical Engineering;

   Sammanfattning : In industrial structural dynamics problems, linear FE-models commonly serve to represent the global structural behavior. However, when test data are available they often show evidence of nonlinear dynamic characteristics. In that case, an initial linear model may be judged insufficient in representing the dynamics of the structure. LÄS MER