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Visar resultat 1 - 5 av 27 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Modelling Tools for Quieter Vehicles : Effective Vibro-Acoustical Modelling of Rotationally Symmetric Structures Consisting of Visco-Elastic and Poro-Elastic Media

    Författare :Martin Östberg; Leif Leif Kari; Ines Lopez; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; Akustik;

    Sammanfattning : .... LÄS MER

  3. 2. Structure-borne sound properties of vibration isolators

    Författare :Leif Kari; KTH; []
    Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : This thesis consists of four papers concerning the audibledynamic stiffness of a vibration isolator; includingmeasurements and theoretical modeling. The study focus isrubber isolators, being the most popular material in theaudible frequency domain - though the measurement principlealso applies to other resilient elements. LÄS MER

  4. 3. Low Frequency Impact Sound in Timber Buildings : Simulations and Measurements

    Författare :Jörgen Olsson; Andreas Linderholt; Leif Kari; Linnéuniversitetet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Low-frequency; impact sound; light weight floor; timber joist floor; tapping machine; multi-storey timber building; frequency response functions.; Stegljud; Byggteknik; Civil engineering;

    Sammanfattning : An increased share of construction with timber is one possible way of achieving more sustainable and energy-efficient life cycles of buildings. The main reason is that wood is a renewable material and buildings require a large amount of resources. LÄS MER

  5. 4. Numerical modelling and analysis of friction contact for turbine blades

    Författare :Mohammad Afzal; Leif Kari; Viktor Berbyuk; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : High cycle fatigue failure of turbine and compressor blades due to resonance in the operating frequency range is one of the main problems in the design of gas turbine engines. To suppress excessive vibrations in the blades and prevent high cycle fatigue, dry friction dampers are used by the engine manufacturers. LÄS MER

  7. 5. On efficient and adaptive modelling of friction damping in bladed disks

    Författare :Mohammad Afzal; Leif Kari; Ines Lopez Arteaga; Muzio M Gola; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High cycle fatigue; Friction contact; Jacobian matrix; Shroud contact; Strip damper; Multiharmonic balance method; Contact stiffness; Cyclic symmetry; Nodal diameter; Magnetostrictive actuator; Magnetic field; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This work focuses on efficient modelling and adaptive control of friction damping in bladed disks. To efficiently simulate the friction contact, a full-3D time-discrete contact model is reformulated and an analytical expression for the Jacobian matrix is derived that reduces the computation time drastically with respect to the classical finite difference method. LÄS MER