Vibration source identification of a heavy commercial vehicle cab based on operational transfer path analysis

2019 ◽  
Vol 234 (2-3) ◽  
pp. 669-680
Author(s):  
Zhiyong Zhang ◽  
Da Pan ◽  
Wenguang Wu ◽  
Caixia Huang
Keyword(s):  
Path Analysis ◽  
Source Identification ◽  
Commercial Vehicle ◽  
Amplitude Spectrum ◽  
Vibration Source ◽  
Energy Propagation ◽  
Transfer Path ◽  
Contribution Analysis ◽  
Transfer Path Analysis ◽  
Heavy Commercial Vehicle

Operational transfer path analysis is applied in this study to identify the vibration source and its critical transfer path. A simple analytical five-degrees-of-freedom mechanical isolation system is first taken as an example to illustrate the analysis flow and to validate the accuracy of operational transfer path analysis. The acceleration amplitude spectrum of the receiver is used to prove the accuracy, and the path contribution of each path is used to identify the critical path. Operational transfer path analysis is then applied to the cab mount system of a heavy commercial vehicle to identify the vibration source and its critical transfer path. The vibration energy propagation capabilities from the four cab mounts to the driver’s seat are analyzed by operational transfer path analysis with the path contribution analysis, and the maximum vibration source is identified by the path operation contribution analysis. The analysis and evaluation method of the operational transfer path analysis introduced in this study can provide a research foundation and reference for vibration or noise source identification in mechanical systems.

scholarly journals Comparison of Estimation Techniques for Vibro-Acoustic Transfer Path Analysis

2006 ◽  
Vol 13 (4-5) ◽  
pp. 459-467 ◽  
Author(s):  
Paulo Eduardo França Padilha ◽  
José Roberto de França Arruda
Keyword(s):  
Path Analysis ◽  
Mechanical Impedance ◽  
Inversion Method ◽  
Energy Propagation ◽  
Transfer Path ◽  
High Impedance ◽  
Source Impedance ◽  
The Matrix ◽  
Matrix Inversion Method ◽  
Transfer Path Analysis

Vibro-acoustic Transfer Path Analysis (TPA) is a tool to evaluate the contribution of different energy propagation paths between a source and a receiver, linked to each other by a number of connections. TPA is typically used to quantify and rank the relative importance of these paths in a given frequency band, determining the most significant one to the receiver. Basically, two quantities have to be determined for TPA: the operational forces at each transfer path and the Frequency Response Functions (FRF) of these paths. The FRF are obtained either experimentally or analytically, and the influence of the mechanical impedance of the source can be taken into account or not. The operational forces can be directly obtained from measurements using force transducers or indirectly estimated from auxiliary response measurements. Two methods to obtain the operational forces indirectly – the Complex Stiffness Method (CSM) and the Matrix Inversion Method (MIM) – associated with two possible configurations to determine the FRF – including and excluding the source impedance – are presented and discussed in this paper. The effect of weak and strong coupling among the paths is also commented considering the techniques previously presented. The main conclusion is that, with the source removed, CSM gives more accurate results. On the other hand, with the source present, MIM is preferable. In the latter case, CSM should be used only if there is a high impedance mismatch between the source and the receiver. Both methods are not affected by a higher or lower degree of coupling among the transfer paths.

Identification of partially coherent sound sources for centrifugal fan

2021 ◽  
Vol 69 (1) ◽  
pp. 66-76
Author(s):  
Chenguang Wang ◽  
Weikang Jiang
Keyword(s):  
Path Analysis ◽  
Mechanical Equipment ◽  
Test Model ◽  
Sound Sources ◽  
Transfer Path ◽  
Partially Coherent ◽  
Contribution Analysis ◽  
Coherent Sources ◽  
Transfer Path Analysis ◽  
Partially Coherent Sources

The signal model with multiple inputs and single output (MISO) is often used for investigating sound sources of vehicles and mechanical equipment, in which transfer path analysis (TPA) and operational transfer path analysis (OTPA) procedure are well known in industry. Sources are completely coherent, as well as completely incoherent in TPA and OTPA models. However, some mechanical devices like centrifugal fans contain not only structure-borne and air-borne sound but also vibrational source and acoustical source. The sources may be partially coherent and cannot be calculated using traditional method. In order to understand the origination of sound from the partially coherent sources of the fan, a MISO model with partially coherent inputs was developed, in which the partially coherent sources were identified by partial singular value decomposition (PSVD) method. Vibration, pressure pulsation and sound signals were measured, and partially coherent sources contribution analysis were used to calculate the contribution of sources quantitatively. A test model was built, and an experiment was conducted to verify that this method is feasible. This method is also suitable for the identification and contribution analysis of sources with partially coherent characteristics, such as automobile exhaust system. This method can calculate the contribution of partially coherent sources, which is not available in other noise source identification methods.

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