Steinhauser, M. (2018). Standardized structure-borne sound acceptance measurements and calculations for rotating machines [Diploma Thesis, Technische Universität Wien]. reposiTUm. https://doi.org/10.34726/hss.2018.56120
Structure-Borne Sound; Power and Force Prediction; Blocked Force; Source Characterization; Virtual Reception Plate Method; Cross-spectrum Method; Mobility Method
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Abstract:
Structure-borne sound faces everyone each single day. Whether in the morning when the coffee machine grinds the coffee beans, on the way to work by train when the air conditioning system produces noise or at home when the washer is running. The purpose of this thesis is to evaluate and predict structure-borne sound power and connection forces between source and receiver in existent or virtual source receiver configurations. Applied methods are the reception plate method, the mobility method and the cross-spectrum method. Prediction of power is only possible with the two first mentioned methods and for connected forces only with the mobility method. Three different analysis-steps concerning the excitation of the receiver were investigated with different vibration damper: single-point excitation, multi-point excitation, and a real structure-borne sound source. The first two steps were simulated and measured, in the step of the real source only measurements were done. Concerning the evaluation with the cross-spectrum method it is often the case to reduce the measurement effort by neglecting certain force and velocity components. Numerical investigations by applying the Finite Element Method were done on two different models with either a single-point connection or a multi-point connection to gain insights how many components have to be respected. By considering only normal components in case of sources which act normally to the connection points good results can be received. In case of other sources detailed investigations have to be done. Two different aluminum plates with three different types of sources were investigated. The measurement of the introduced structure-borne sound sources show good conformity. Prediction of the power or the connected forces is theoretically possible but practical predictions of the power lead to no satisfying results. Therefore, further research effort concerning the prediction is necessary.