In this paper two different Transfer Path Analsis models for the investigation of the sound pressure contributions to the interior compartment noise of a small hydraulic unit were presented, including the measurement of fluid-borne (hydraulic) transfer functions and operational data. The ease of use of acceleration based transfer models on the one hand and the compliance of individual path coupling situations and boundary conditions on the other hand encouraged the introduction and application of a new acceleration based transfer model from blocked force measurements in a hybrid TPA scheme. A method for the indirect calibration of high sound energy flux (volume velocity) was applied for reciprocal transfer function measurements. The hybrid TPA model was compared to an conventional operational MISO path model (OTPA) as an alternative fast in-situ method. Thikhonov Regularisation, usually known from inverse force methods, was successfully applied resulting in higher numerical precision in terms of system identification. The Transfer Path Synthesis showed reasonable results although large deviations of 10 dB between calculated and measured sound pressure can be observed for some frequencies. On the other hand the partial sound contribtions for both models are similar but not consistent over the whole frequency band of interest. High crosstalk for the fluid and the structure-borne path may affect prediction accuracy for the hybrid TPA model whereas the OTPA decorrelates the insitu identified transfer functions inherently, balancing the fluid-borne and structure-borne sound contributions. In general, the simplicity of acceleration based transfer models is confronted with the disadvantage of high error sensitivity due to sensor placement, local structural dynamics and limited interpretability. Finally, it is important to emphasize that Transfer Path Analysis (TPA) still remains an expert NVH tool and its universal applicability is neither guarenteed nor achievable, which turns out notably for rigid coupled compact sources.
Transfer path analysis of compact automotive ancillary assemblies
Analyse des Übertragungswegs kompakter, automobiler Zusatzgeräte
2010
6 Seiten, 1 Bild, 1 Tabelle, 3 Quellen
(nicht paginiert)
Aufsatz (Konferenz)
Datenträger
Englisch
Failure analysis of automotive assemblies (Part I)
Tema Archiv | 2002
|Failure analysis of automotive assemblies (Part II)
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