| 1. |
- Traunmüller, Hartmut
(författare)
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Phase vowels
- 1987
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Ingår i: The psychophysics of speech perception. - Dordrecht : Nijhoff in cooperation with NATO Scientific Affairs Division. - 902473536X ; , s. 377-384
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Sunnersjö, Staffan, 1948, et al.
(författare)
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Hydrodynamic inertia and damping of ship hull vibrations
- 1988
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Ingår i: Transactions of the Royal Institute of Naval Architects. - 0035-8967. ; 130, s. 107-117
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Tidskriftsartikel (refereegranskat)abstract
- The entrained water plays an important role in ship hull vibrations. The classic Lewis method for calculation of hydrodynamic added mass has some inherent shortcomings that can result in insufficient accuracy, particularly for higher order modes. This is essentially due to the fact that the Lewis method uses a diagonal mass matrix that is dependent on the mode of vibration, while the physical reality is more accurately represented by a mode-independent, full mass matrix. Such full mass matrices can be calculated with Finite Volume or Source- Sink methods, which, however, require extensive computer calculations with detailed input data. A method is presented with which the Lewis transform can be used to determine a full mass matrix and gives very good agreement with Finite Volume calculations for a test case on a small ship. The Finite Volume calculations have also been used to study damping …
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| 3. |
- Gudmundson, Peter
(författare)
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Eigenfrequency changes of structures due to cracks, notches or other geometrical changes
- 1982
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Ingår i: Journal of the mechanics and physics of solids. - : Elsevier BV. - 0022-5096 .- 1873-4782. ; 30:5, s. 339-353
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Tidskriftsartikel (refereegranskat)abstract
- A first order perturbation method is presented which predicts the changes in resonance frequencies of a structure resulting from cracks, notches or other geometrical changes. The eigenfrequency changes due to a crack are shown to be dependent on the strain energy of a static solution which is easily obtainable for small cracks and other small cut-outs. The method has been tested for three different cases, and the predicted results correlate very closely to experimental and numerical results.
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| 4. |
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| 5. |
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| 6. |
- Bergdahl, Lars, 1943
(författare)
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Vågor och vågkrafter
- 1984
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Kompendium i Kursen Vågor och vågkrafter. Speciellt borr- och produktionsplattformar för offshoreindustrin
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| 7. |
- Boström, Anders E, 1951, et al.
(författare)
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Elastic wave scattering by a three-dimensional inhomogeneity in an elastic half space
- 1980
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Ingår i: Wave Motion. - 0165-2125. ; 2, s. 335-353
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we will consider scattering of elastic waves in a half space. The half space is an isotropic, linear and homogeneous medium except for a finite inhomogeneity. The T-matrix method (also called the "extended boundary condition method" or "null field approach") is extended to derive expressions for the elastic field inside the half space and the surface field on the interface. The assumptions on the source that excites the half space are fairly weak. In the numerical applications found in this paper we assume a Rayleigh surface wave to be the incoming field, and we only compute the surface displacements. We make illustrations on some simple type of scatterers (spheres and spheroids; the latter ones can be arbitrarily oriented).
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| 8. |
- Boström, Anders E, 1951
(författare)
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Multiple scattering of elastic waves by bounded obstacles
- 1980
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Ingår i: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 67, s. 399-413
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Tidskriftsartikel (refereegranskat)abstract
- The transition matrix method for stationary elastic waves is extended to a great class of obstacles characterized by piecewise constant properties. First, the translation properties of the basis functions is used to treat two and, then, then several homogeneous obstacles, and thereafter an obstacle with consecutively enclosing layers is considered. It is then indicated how these two basic methods of combination can be applied tp treat more complex cases, including an obstacle consisting of several nonenclosing parts. Finally, we give some numrecal applications of configurations of spherical and nonspherical obstacles in and below the resonance region.
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| 9. |
- Boström, Anders E, 1951
(författare)
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Scattering by a smooth elastic obstacle
- 1980
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Ingår i: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 67, s. 1904-1913
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Tidskriftsartikel (refereegranskat)abstract
- In the present paper we adapt the transition matrix method to the case of a smooth elastic obstacle. The boundary conditions employed are discussed in some detail and are seen to be responsible for the fact that the rather complicated formal solution in many respects resembles that of an elastic obstacle in a fluid. Comparisons are made between the smooth and the usually employed welded obstacles, and for spheres approximate expressions are given for the transition matrices in the long wavelength limit. Numerical results (cross sections and surface stresses) are given for spheres and spheroids, and it is then seen that often the smooth and welded obstacles, at least qualitatively, show similar features.
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| 10. |
- Boström, Anders E, 1951, et al.
(författare)
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Scattering of a pulsed Rayleigh wave by a spherical cavity in an elastic half space
- 1983
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Ingår i: Wave Motion. - 0165-2125. ; 5, s. 137-143
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Tidskriftsartikel (refereegranskat)abstract
- The time-dependant scattering by a spherical cavity in an elastic half space is considered. The incoming wave is a pulsed Rayleigh wave. The stationary part of the problem is solved by the T-matrix method, and an integration in frequency is perforemd with a modified gaussian weight function. The displcsement components at some points on the surface of the half space are computed and shown in a number of plots.
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