Search for dissertations about: "Harmonic expansion"

Showing result 1 - 5 of 15 swedish dissertations containing the words Harmonic expansion.

2. 1. Modelling tools for quieter vehicles : Waves in poro– and visco–elastic continua

   Author : Martin Östberg; Leif Kari; Jenny Jerrelind; Sergey Sorokin; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vibro-acoutics; poro-elastic; visco-elastic; reduced models; Harmonic expansion; wave guide;

   Abstract : New modelling tools intended to contribute to the development of components for quieter vehicles are developed. The tools are based on continuum models for wave propagation in poro– and visco–elastic media. By using geometric attributes of the studied components, the computational cost may be radically decreased compared to traditional methods. READ MORE

4. 2. Computational investigation of interface structure and composition in cemented carbides at finite temperatures

   Author : Erik Fransson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Molecular dynamics; Hard Metals; Interfacial free energies; Monte Carlo; Cemented carbides; Force constants; Cluster expansion;

   Abstract : WC-Co cemented carbides combine superb hardness with high toughness making them ideal for usage in high-speed machining of steels and in wear resistance tools. These excellent mechanical properties are to a large extent dependent on the microstructure and thus the interfacial properties of the material. READ MORE

5. 3. Dynamic analyses of structures with applied rubber

   Author : Magnus Alvelid; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Viscoelasticity; Series expansion; Finite; Fractional calculus; Optimization;

   Abstract : The aim with the present thesis has been to develop efficient, practical and accuratemethods in order to model rubber in dynamic analyses, with emphasis on passive constrainedlayer damping materials. A fractional order viscoelastic constitutive model ismapped onto experimental data from a measurement standard using a vibrating beamtechnique. READ MORE

6. 4. Managing uncertainties through efficient calculation of transients and harmonic propagation in power systems

   Author : Oscar Lennerhag; Math Bollen; Jan Lundquist; David Thomas; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Overvoltages; harmonics; uncertainties; stochastic methods; Electric Power Engineering; Elkraftteknik;

   Abstract : The electric power system is undergoing changes including large-scale introduction of renewable energy sources together with HVDC/FACTS, changes in the network such as increased amount of high voltage cables, industrial electrification, and changes in the load composition. These changes will impact the system in different ways and lead to challenges that must be addressed to facilitate planning, dimensioning, and operation of the system in a secure and economical way. READ MORE

7. 5. Creep modeling and first-principles investigation of high-temperature alloys

   Author : Jing Zhang; Pavel A. Korzhavyi; Rolf Sandström; Gunther Eggeler; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Austenitic stainless steels; Nickel-based superalloys; Fundamental creep models; EMTO-CPA method; Quasi-harmonic Debye model; Thermo-mechanical properties; High temperatures.; Teknisk materialvetenskap; Materials Science and Engineering;

   Abstract : Stainless steels and nickel-based superalloys are materials that have been widely used to manufacture components servicing at high temperatures. Creep strength is one of the most important properties in such conditions. READ MORE