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- 2009 (3) (entfernen)
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- Englisch (3)
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- Acoustics (1)
- Active control (1)
- Impacts (1)
- Noise control (1)
- SEA (1)
Acoustic emission (AE) sources caused by partial discharges in solid dielectric devices like transition joints or outdoor terminations are investigated. Together with a prepared high voltage cable end this device forms a multilayer structure. The hypothesis is that due to the high damping of polymeric insulation materials no AE signal can be detected on the surface of the prescribed structures. An analytical technique is used to determine the transmission for a typical multilayer insulation. For quantitative computations it is necessary to know the material properties such as complex Young´s modulus, density and the Poisson´s ratio. Since the properties found in the literature were not fully satisfactory, measurements had to be done. The experimental setup and the results are shortly presented. Finally it will be shown that the transmission path plays not the significant role as was assumed in the beginning.
The diffuse field assumption employed in Statistical Energy Analysis (SEA) and in statistical
room acoustics is violated for source and receiver positions close to boundaries or discontinuities.
An approach is suggested to include the correction made by Waterhouse based on
spherical Bessel functions in SEA predictions. With this modification the SEA results will be
augmented by a position dependence and an additional frequency dependence. The approach
is extended and demonstrated for plate-like structures with different boundary conditions. The
validity of the approach is confirmed by means of comparisons with modal analysis and finite
element calculations.