scholarly journals Reliability Analysis of Random Vibration Transmission Path Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Zhao ◽  
Yi-Min Zhang
Keyword(s):  
Random Vibration ◽  
Vibration Source ◽  
Vibration Transmission ◽  
Transmission Path ◽  
Transfer Path ◽  
Practical Project ◽  
Mathematical Expressions ◽  
The Matrix ◽  
Path System ◽  
Element Theory

The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.

Reliability of Vibration Transfer Path Systems

2015 ◽  
Vol 752-753 ◽  
pp. 778-783 ◽  
Author(s):  
Wei Zhao ◽  
Ping Chen ◽  
Yi Min Zhang
Keyword(s):  
Finite Element ◽  
Theoretical Foundation ◽  
Stochastic Finite Element ◽  
Dynamic Design ◽  
Transfer Path ◽  
Practical Project ◽  
Mathematical Expressions ◽  
Matrix Calculus ◽  
The Matrix ◽  
Element Theory

Based on the matrix calculus, the generalized second moment technique and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was presented. The transfer reliability of vibration transfer path systems with uncertain path parameters including mass and stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were obtained. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most uncertain factors can be considered to solve the random problems for vibration transfer path systems.

Random Response Analysis of Vibration Transfer Path Systems with Translational and Rotational Motions

2013 ◽  
Vol 423-426 ◽  
pp. 1543-1547
Author(s):  
Wei Zhao ◽  
Na Zhou ◽  
Yi Min Zhang
Keyword(s):  
Random Vibration ◽  
Response Analysis ◽  
Random Response ◽  
First Order ◽  
Transfer Path ◽  
Mathematical Expressions ◽  
Path System ◽  
Rotational Motions ◽  
Vector Valued Functions ◽  
Vector Valued

This paper based on the generalized probabilistic perturbation finite element method solves the random response analysis problem of vibration transfer path systems with translational and rotational motions. The effective random response analysis approaches are achieved using Kronecker algebra, matrix calculus, generalized second moment technique of vector-valued functions and matrix-valued functions. For the vibration transfer path system with multi-dimensional paths, the random response is described correctly and expressly in time domain as uncertain factors, which include mass, damping, stiffness and position, are considered. The mathematical expressions of the first order and second order moments for the random vibration response of vibration transfer path are obtained. According to the corresponding numerical example, the results of calculation are consistent with the results of Monte-Carlo simulation, which shows the method is feasible theoretically.

scholarly journals Research on Reliability for Servo Turret Based on Vibration Transmission Path System with Stiffness Degradation Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Li-sha Zhu ◽  
Lian-sheng Li ◽  
Shang-jie Li ◽  
Shan Wang
Keyword(s):  
Excitation Frequency ◽  
System Stability ◽  
Stiffness Degradation ◽  
Initial Time ◽  
Random Parameters ◽  
Vibration Transmission ◽  
Transmission Path ◽  
Reliability Sensitivity ◽  
Path System ◽  
Peak Value

The stiffness degradation of the servo turret will inevitably lead to accuracy reduction of the cutter head and the tool change. Considering the degradation process of servo turret with stiffness, by introducing the stiffness cumulative damage theory into the vibration differential equation, combined with stochastic finite element method and reliability theory, the mathematical model of the reliability and reliability sensitivity for vibration transmission path system with random parameters was established. Taking a typical power servo turret for example, the reliability and the reliability sensitivity to each random parameter at the mean value with the excitation frequency and time were obtained. The results showed that the shift of the reliability and reliability sensitivity to random parameters with time was caused by the stiffness degradation, the peak value of reliability sensitivity fluctuated with time, and the peak value in the frequency domain at the initial time was not necessarily the maximum value in the time domain. The accuracy of the proposed method was further proved by the Monte Carlo method. Optimizing sensitive parameters could enhance the system stability and effectively prevent the resonance failure caused by the change of the resonance region.

Vibration transmission path analysis of underwater vehicle power plant based on TPA power flow

2021 ◽  
pp. 147509022110240
Author(s):  
Yang Yang ◽  
Guang Pan ◽  
Shaoping Yin ◽  
Ying Yuan
Keyword(s):  
Power Plant ◽  
Path Analysis ◽  
Power Flow ◽  
Sea Water ◽  
Low Frequency ◽  
Underwater Vehicle ◽  
Vibration Energy ◽  
Vibration Transmission ◽  
Transmission Path ◽  
Transfer Path

In order to obtain the energy contribution of all paths transmitting vibration from the underwater vehicle power plant to the outer shell, a new method named TPA (Transfer Path Analysis) power flow which combines classical TPA and power flow theory was proposed. Calculation results showed that isolators were the critical paths for transmitting vibration energy to the shell in low frequency band. In addition the main engine and sea water pump were critical vibration sources, which provided directions for reducing the vibration energy transmitted from vibration sources to the target body. To the best of our knowledge, this was the first time to assess the vibration transmission path of the underwater vehicle by TPA power flow method. This method can be employed in other works that need to evaluate the contribution of vibration energy.

Commercialization of Active Isolation for Jet Aircraft

1997 ◽  
Author(s):  
Steve C. Southward ◽  
Douglas E. Ivers ◽  
Geoff C. Nicholson
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Acoustic Noise ◽  
Development Program ◽  
Flight Test ◽  
Test Time ◽  
Vibration Source ◽  
Noise And Vibration ◽  
Transmission Path ◽  
Active Isolation

Abstract Active Noise and Vibration Control (ANVC) technology is a proven solution for noise and vibration problems in aircraft. The challenges in commercializing this solution range from the development issues of choosing the best actuation, sensor, and control technology to obtaining sufficient flight test time and satisfying FAA requirements. This paper examines significant case histories in the progression of the Lord active vibration control program from conception to market. Throughout the development program, several important discoveries were made regarding the performance, reliability, and economics of Active Isolation Systems (AIS) in jet aircraft. First, practical speaker-based solutions cannot achieve global acoustic noise cancellation for engine tones above about 200 Hz. A comparatively small array of structural actuators placed in the dominant transmission path, such as in or near the engine mounts, are capable of global cancellation in the cabin up to at least 500 Hz. Second, the performance is generally better when cabin microphones are used as error sensor inputs because the AIS control system can compensate for flanking paths better than if accelerometers are used as error sensors. Third, when the actuators are placed in the dominant transmission path and close to the vibration source, the control system will simultaneously achieve global acoustic noise reduction in the cabin and vibration reduction in the aircraft structure without affecting the engine casing vibration levels.

scholarly journals Rubber Stiffness Optimization for Floor Vibration Attenuation of a Light Bus Based on Matrix Inversion TPA

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hui Shi ◽  
Wenku Shi ◽  
Changhai Yang ◽  
Guozheng Liu ◽  
Zhaomeng Fan ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Optimization Procedure ◽  
Matrix Inversion ◽  
Vibration Test ◽  
Transfer Path ◽  
Stiffness Optimization ◽  
Market Competitiveness ◽  
Vibration Attenuation ◽  
The Matrix ◽  
Floor Vibration

The NVH characteristics of light buses are a very important performance for market competitiveness. To solve the serious floor vibration of a light bus at speed of 60 km/h and 90 km/h, we first derive the matrix inversion TPA (MITPA) method, and then transfer path contribution is analyzed by applying matrix inversion TPA with TPA model establishment, operational vibration test, and FRF measurement. Next, the energy decoupling rate of the powertrain mount system (PMS) is optimized by rubber stiffness optimization based on the path contribution analysis taking both amplitude and phase into consideration. The optimized natural frequencies and energy decoupling rate indicate that energy decoupling rate (EDR) of each DoF of the powertrain mount system is improved. Finally, to verify the optimization effect, this paper implements an operational vibration test with optimized mount installed. The results indicate that floor vibration of postoptimization is improved significantly compared with that of preoptimization. This paper offers a method for engineers to improve vibration problem of vehicle by combining experimental TPA for identification of dominant paths with optimization procedure.

Operational Transfer Path Analysis Based on Signal Decoupling

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Leiming Song ◽  
Qing Gui ◽  
Hao Chen ◽  
Haifei Bai ◽  
Yu Sun
Keyword(s):  
Path Analysis ◽  
High Speed ◽  
Peak Frequency ◽  
Experimental Comparison ◽  
Strongly Coupled ◽  
Transmission Path ◽  
Transfer Path ◽  
Decoupling Analysis ◽  
Multiple Unit ◽  
Transfer Path Analysis

Abstract This study proposes an input decoupling analysis method based on the pulse test and the traditional operational transfer path analysis (OTPA) method for the OTPA transmission path analysis when the input is strongly coupled, and the algorithm is verified for analysis optimization of results. An experimental model of the dual excitation source is established in the laboratory. Experimental comparison studies show that the OTPA method, which is based on signal decoupling, inhibits the influence of cross-coupling among the source signals during OTPA analysis and effectively improves the accuracy of the transmission path test and analysis. The OTPA method is applied to analyze the transfer path of the vibration and noise of the carriages of the electric multiple unit (EMU) train (a high-speed train in China). The false peak frequency in the traditional OTPA method is eliminated, and the accuracy of the analysis is improved.

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