Search for dissertations about: "acoustical"

Showing result 1 - 5 of 51 swedish dissertations containing the word acoustical.

2. 1. Acoustical properties of earplugs

   Author : Per Hiselius; Teknisk akustik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; vibration and acoustic engineering; vacuum technology; hydraulics; Mechanical engineering; acoustic modelling; objective measurement; insertion loss; earplugs; HPE; HPD; hearing protectors; Two-Port; Four-Pole; attenuation; electro acoustics; acoustics;

   Abstract : In this study an experimental setup for measurements of high impedance objects in ducts, yielding the acoustical Two-Port properties of the object, is applied to earplugs. A frequently used experimental setup for measuring objective acoustical properties of earplugs is that of artificial ears. Great effort is spent on duplicating the human ear. READ MORE

4. 2. Factors Governing Acoustical Comfort In Vehicle Compartments

   Author : Oliver Jung; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Driving Noise; Lombard Effect; Sound Quality; Psychoacoustics; Acoustical Comfort; Emotions; Vehicle Acoustics; Speech Communication; Cognition Psychology; Speech Quality;

   Abstract : A pleasant interior sound field is an essential comfort criterion for vehicle occupants.The pleasantness is mainly influenced by a low overall sound pressurelevel. Further minimization of driving noise, however, is constricted on thelower end by physical limitations. READ MORE

5. 3. Acoustical Characteristics of Aircraft Panels

   Author : Bilong Liu; Leping Feng; Jie Pan; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; sound transmission loss; stiffener; stiffening; aircraft panel; cylindrical shell; turbulent boundary layer; TBL; noise; sound radiation; Acoustics; Akustik;

   Abstract : A deterministic approach based on a modal expansion and modal receptance method has been developed to evaluate the airborne sound insulation of aircraft panels with stringer and ring frame attachments. Furthermore, this method was extended to predict the noise radiation of stiffening panel subjected to TBL excitation. READ MORE

6. 4. Effective vibro-acoustical modelling of rubber isolators

   Author : Michael Coja; Leif Kari; Wolfgang Kropp; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Applied mechanics; Rubber isolator; Bush mounting; Dynamic stiffness; Waveguide; Fractional derivatives; Mode-matching; Pre-compressed; Prestrain; Preload; Predeformation; Viscoelasticity; Dispersion; Teknisk mekanik; Engineering mechanics; Teknisk mekanik;

   Abstract : This thesis, gathering four papers, concerns the enhancement in understanding and modelling of the audible dynamic stiffness of vibration rubber isolators including experimental measurements. Paper A studies the performances of three different types of vibration isolator using an indirect measurement technique to estimate the blocked dynamic transfer stiffness of each specimen. READ MORE

7. 5. Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery

   Author : Kristian Haller; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; nonequilibrium recovery; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate; constant strain sweep;

   Abstract : A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. READ MORE