Time-domain Transfer Path Modal and Contribution Analysis of Moving Noise Sources

Generally speaking, a vibration system consists of three parts: vibration resource, vibration transfer path, and vibration receiver. Based on the dynamic sensitivity technique, this paper proposes a method for evaluating the contribution of each vibration transfer path to the dynamic response of the vibration receiver. Nonlinear stiffness is an important factor in causing the nonlinearity of vibration systems. Taking sensitivity as the evaluation criteria, we present an effective approach for estimating the influence of nonlinear stiffness in vibration transfer paths on the dynamic response of the vibration receiver. Using the proposed method, the sensitivity of the vibration system with multiple and/or multidimensional transfer paths could be determined in the time domain.

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The Mathematical Model on Crosstalk Effect of Airborne Noise Sources and Verification based on Comparison between Transfer Path Analysis Methods

Transactions of the Korean Society for Noise and Vibration Engineering ◽

10.5050/ksnvn.2008.18.9.943 ◽

2008 ◽

Vol 18 (9) ◽

pp. 943-951 ◽

Cited By ~ 3

Keyword(s):

Mathematical Model ◽

Path Analysis ◽

Noise Sources ◽

Transfer Path ◽

Analysis Methods ◽

Airborne Noise ◽

Transfer Path Analysis ◽

The Mathematical Model

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Time-Domain Substructure Transient Vibration Transfer Path Analysis Based on Time-Varying Frequency Response Functions under Operational Excitations

Shock and Vibration ◽

10.1155/2019/2030326 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16

Author(s):

Rong He ◽

Hong Zhou

Keyword(s):

Path Analysis ◽

Frequency Response ◽

Time Domain ◽

Time Varying ◽

Response Functions ◽

Transient Vibration ◽

Transfer Path ◽

Time Varying Systems ◽

Transfer Path Analysis ◽

The Time Domain

The time-domain substructure inverse matrix method has become a popular method to detect and diagnose problems regarding vehicle noise, vibration, and harshness, especially for those impulse excitations caused by roads. However, owning to its reliance on frequency response functions (FRFs), the approach is effective only for time-invariable linear or weak nonlinear systems. This limitation prevents this method from being applied to a typical vehicle suspension substructure, which shows different nonlinear characteristics under different wheel transient loads. In this study, operational excitation was considered as a key factor and applied to calculate dynamic time-varying FRFs to perform accurate time-domain transient vibration transfer path analysis (TPA). The core idea of this novel method is to divide whole coupled substructural relationships into two parts: one involved time-invariable components; normal FRFs could be obtained through tests directly. The other involved numerical computations of the time-domain operational loads matrix and FRFs matrix in static conditions. This method focused on determining dynamic FRFs affected by operational loads, especially the severe transient ones; these loads are difficult to be considered in other classical TPA approaches, such as operational path analysis with exogenous inputs (OPAX) and operational transfer path analysis (OTPA). Experimental results showed that this new approach could overcome the limitations of the traditional time-domain substructure TPA in terms of its strict requirements within time-invariable systems. This is because in the new method, time-varying FRFs were calculated and used, which could make the FRFs at the system level directly adapt to time-varying systems from time to time. In summary, the modified method extends TPA objects studied in time-invariable systems to time-varying systems and, thus, makes a methodology and application innovation compared to traditional the time-domain substructure TPA.

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Mechanism of interior noise generation in high-speed vehicle based on anti-noise operational transfer path analysis

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407020937219 ◽

2020 ◽

Vol 235 (1) ◽

pp. 273-287

Author(s):

Ningning Liu ◽

Yuedong Sun ◽

Yansong Wang ◽

Pei Sun ◽

Wenwu Li ◽

...

Keyword(s):

Path Analysis ◽

High Speed ◽

Noise Signal ◽

Interior Noise ◽

Analysis Model ◽

Noise Sources ◽

Wind Noise ◽

Transfer Path ◽

Transfer Path Analysis ◽

Path Analysis Model

Owing to the continuous development of the automobile industry, increasingly stringent performance requirements for noise, vibration, and harshness of automobiles are being presented. Interior noise control in high-speed vehicles has not been adequately addressed, owing to the complex mechanism of noise generation. As simulations performed previously focused on vehicle wind noise and tyre noise cannot adequately predict the effect on passenger ear-side noise, these issues are investigated in this study. Their effects on passengers are investigated using transfer path analysis. An anti-noise operational transfer path analysis is proposed to study noise generated in high-speed vehicles. The established anti-noise operational transfer path analysis model can eliminate crosstalks between noise source signals of different transmission paths. The model is validated by comparing the measured and calculated values of the anti-noise operational transfer path analysis model. The coherence of the input noise signal and the ear-side noise signal of the passenger is assessed using coherence analysis. By calculating and categorising the contributions of different noise sources in different locations and types, the main noise sources affecting passenger comfort are determined. The result indicates that the main noise sources affecting the passenger’s ear-side noise change from engine noise to left-A wind noise and tyre radiation noise with increasing vehicle speed, in which the proportion also increase. The proposed anti-noise operational transfer path analysis is suitable for the interior-noise analysis of high-speed vehicles, and this study may serve as a reference for future studies regarding active and passive noise control in high-speed vehicles.

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Time domain transfer coupling in antennas

2017 International Conference on Electromagnetics in Advanced Applications (ICEAA) ◽

10.1109/iceaa.2017.8065288 ◽

2017 ◽

Author(s):

A. Shlivinski

Keyword(s):

Time Domain ◽

Domain Transfer

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A Research for the Planetary Gear Noise Development in FF 6th Speed Automatic Transmission

Volume 8: 11th International Power Transmission and Gearing Conference; 13th International Conference on Advanced Vehicle and Tire Technologies ◽

10.1115/detc2011-47129 ◽

2011 ◽

Author(s):

Hyun-Ku Lee ◽

Koo-Tae Kang ◽

Moo-Suk Kim ◽

Jin-Wook Hur

Keyword(s):

Gear Tooth ◽

Automatic Transmission ◽

Planetary Gear ◽

The Sun ◽

Noise Levels ◽

Noise Sources ◽

Valve Body ◽

Gear Noise ◽

Radiated Noise ◽

Transfer Path

In order to improve the planetary gear noise of the new developed 6th speed automatic transmission, it needs to understand noise mechanism. Basically, many transmission’s components have an effect on the gear noise. In this paper, planetary gear noise sources which are influenced by gear tooth shapes and backlash among the gears, position of pinion gears, and misalignment of the sun gear are studied and experimented. Also, transfer-path likewise one-way clutch contacted between the carrier and case, and valve-body covers are also researched to reduce the transferred vibration and radiated noise levels. After developing the planetary gear noise, its evaluation specification is adapted to EOL (end of line) equipment to check the transmission’s noise quality in the factory.

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