Search for dissertations about: "Eigenfrequencies"

Showing result 1 - 5 of 28 swedish dissertations containing the word Eigenfrequencies.

2. 1. Noise, eigenfrequencies and turbulence behavior of a 200 kW H-rotor vertical axis wind turbine

   Author : Erik Möllerström; Jonny Hylander; Fredric Ottermo; Hans Bernhoff; Göran Sidén; Mats Åbom; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; eigenfrequency; semi-guy-wired tower; noise emission; sound power level; microphone array; turbulence intensity; power curve; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Abstract : Vertical-axis wind turbines (VAWTs) have with time been outrivaled by the today more common and economically feasible horizontal-axis wind turbines (HAWTs). However, VAWTs have several advantages which still make them interesting, for example, the VAWTs can have the drive train at ground level and it has been argued that they have lower noise emission. READ MORE

4. 2. Vibration of sandwich beams

   Author : Daniel Backström; Anders Nilsson; Goran Pavic; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; Akustik;

   Abstract : Some aspects and properties of the lateral vibration of sandwich beams are investigated, including the concept of apparent bending stiffness and shear modulus, allowing the sandwich beam dynamics to be approximately described by classical beam theory. A sixth order beam model is derived including boundary conditions, and the free and forced response of some beam configurations analyzed. READ MORE

5. 3. Dynamics of Structures with Thin Piezoelectric Layers

   Author : Gunnar Johansson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : The subject of this thesis is dynamics of structures with thin piezoelectric layers. Piezoelectric materials are used in sensor and actuators and common applications for these are vibration damping, ultrasonic transducers, buzzards and more. READ MORE

6. 4. Reliable hp finite element computations of scattering resonances in nano optics

   Author : Juan Carlos Araujo-Cabarcas; Christian Engström; David Cohen; Mats G. Larson; Jeffrey Ovall; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Scattering resonances; Helmholtz problems; pseudospectrum; Lippmann-Schwinger equation; finite element methods; nonlinear eigenvalue problems; spurious solutions;

   Abstract : Eigenfrequencies are commonly studied in wave propagation problems, as they are important in the analysis of closed cavities such as a microwave oven. For open systems, energy leaks into infinity and therefore scattering resonances are used instead of eigenfrequencies. READ MORE

7. 5. Dynamic Equations for Spherical, Orthotropic and Piezoelectric Cylindrical Shells Using the Power Series Method

   Author : Reza Okhovat; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shell equations; cylindrical shell; eigenfrequency.; piezoelectricity; Shells; Hamilton’s principle; surface differential operators; recursion relations; spherical shell; orthotropic; dynamics;

   Abstract : Shells are commonly used in many branches of engineering, and have therefore beeninvestigated for a number of different types of shells. A shell is considered to be curved aplate with small thickness compared both to the other geometrical dimensions as well asto the wavelengths of importance. READ MORE