Brake Moan Noise Study through Experimental and Operational Modal Analysis Techniques in a Passenger Car

Author(s):  
Alexis Klauber Chaia Kléperon ◽  
Robson Demétrius Araújo Abreu ◽  
Rômulo Morais Bitencourt ◽  
Francis José Marochi Almeida
2017 ◽  
Author(s):  
Alexis Klauber Chaia Kléperon ◽  
Robson Demétrius Araújo Abreu ◽  
Rômulo Morais Bitencourt ◽  
Francis José Marochi Almeida

Author(s):  
Lara Mª Erviti Calvo ◽  
Gorka Agirre Castellanos ◽  
Igor Alonso Portillo

Nowadays the application of experimental modal analysis techniques on railway vehicles is gaining importance. A correct identification of modal characteristics allows improving the dynamic behavior design of the vehicle and so reaching higher running speeds and accomplishing better comfort levels. So far, in the railway sector only conventional modal analysis techniques have been used. With these techniques, the modal parameters are determined during a static test by measuring the responses of the system to one or multiple known forces. This paper presents the application of the Operational Modal Analysis (OMA) technique on a railway vehicle. This technique determines the modal parameters employing only the responses of the system to an unknown excitation. In this way, the data to be used can be acquired during on track test which presents three main advantages. The first one is that the nonlinear components of the suspensions are working in their normal operating condition which is difficult to achieve during a static test. The second one is that the wheel spinning effect is taken into account. Finally, the test can be combined with other type of track tests, reducing the period of time before delivery of the vehicle to the client. In the case under study, the OMA technique is applied by means of commercial software to measurements performed on a passengers train. The modal parameters obtained for the carbody and one of the bogies are presented.


2012 ◽  
Vol 19 (5) ◽  
pp. 1085-1097 ◽  
Author(s):  
Gert De Sitter ◽  
Christof Devriendt ◽  
Patrick Guillaume

Recently it has been shown that also transmissibilities can be used to identify the modal parameters. This approach has several advantages: because of the deterministic character of the transmissibility functions, the estimated parameters are more accurate than the results obtained with the power spectra based operational modal analysis techniques. Another advantage is that the transmissibility functions do not depend on the colouring of the unknown forces. A disadvantage of the transmissibility based operational modal analysis techniques is that non-physical modes show up in the stabilisation diagrams. In this contribution it will first be shown that those non-physical modes will show up when traditional stabilisation diagrams are used. In a second step, a new approach of selecting the physical modes out of a set of estimated modes will be discussed and the new approach will be validated using data generated with an acoustical Finite Element Model. Finally, the approach will be validated using real acoustical data.


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