scholarly journals Full Vehicle Vibration and Noise Analysis Based on Substructure Power Flow

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zhien Liu ◽  
Shuai Yuan ◽  
Shenghao Xiao ◽  
Songze Du ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Power Flow ◽  
Vibration Isolation ◽  
Noise Analysis ◽  
Solution Process ◽  
Low Frequency ◽  
Vehicle Body ◽  
Frequency Noise ◽  
Vehicle Interior ◽  
Computation Efficiency

Combining substructure and power flow theory, in this paper an external program is written to control MSC. Nastran solution process and the substructure frequency response are also formulated accordingly. Based on a simple vehicle model, characteristics of vibration, noise, and power flow are studied, respectively. After being compared with the result of conventional FEM (finite element method), the new method is confirmed to be feasible. When it comes to a vehicle with the problem of low-frequency noise, finite element models of substructures for vehicle body and chassis are established, respectively. In addition, substructure power flow method is also employed to examine the transfer characteristics of multidimensional vibration energy for the whole vehicle system. By virtue of the adjustment stiffness of drive shaft support and bushes at rear suspension lower arm, the vehicle interior noise is decreased by about 3 dB when the engine speed is near 1050 rpm and 1650 rpm in experiment. At the same time, this method can increase the computation efficiency by 78%, 38%, and 98% when it comes to the optimization of chassis structure, body structure, and vibration isolation components, respectively.

scholarly journals Combination of an Improved FRF-Based Substructure Synthesis and Power Flow Method with Application to Vehicle Axle Noise Analysis

2008 ◽  
Vol 15 (1) ◽  
pp. 51-60 ◽  
Author(s):  
C.Q. Liu
Keyword(s):  
Power Flow ◽  
Noise Analysis ◽  
Flow Analysis ◽  
Synthesis Method ◽  
The Body ◽  
Vehicle Body ◽  
Total System ◽  
Simple Formulation ◽  
Substructure Synthesis ◽  
Fea Model

In this paper, an improved FRF-based substructure synthesis method combined with power flow analysis is presented and is used for performing a vehicle axle noise analysis. The major transfer paths of axle noise transmitted from chassis to vehicle body are identified and ranked based on power flows transmitted through bushings between the chassis and body. To calculate the power flows, it is necessary to know the reaction forces and the vibrations at the bushing locations on the body side. To this end, the body is represented in terms of experimentally derived frequency response functions (FRF's) at the bushing locations, and the FRF's are coupled with the FEA model of the chassis for performing a total system dynamic analysis. This paper also describes how the FRF's of the vehicle body and the frequency dependent stiffness data of the bushings can be combined together with a simple formulation to better represent the dynamic characteristics of a full vehicle. A classical example is used to illustrates the concept of the method, and the method is then applied to a vehicle axle noise analysis with detailed procedure. The theoretical predictions are compared with experimentally measured results. Good correlation has been obtained.

Research on Vibration Isolation Parameters of Double-Deck Isolation System of Heat Water Pump

2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Mass Effect ◽  
Transmitted Power ◽  
Intermediate Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Upper Deck ◽  
Vibration Power Flow

Isolation system of the heat water pumps can be simplified as a double sources exciting and double output double-deck vibration isolation system model, expressions of transmitted power flow and vibration speed to the basement are deduced based on the double sources exciting and double output double-deck vibration isolation system electric-force(E-F) analog picture, the curves of power flow and vibration speed transmitted to basement how the upper deck vibration isolation and intermediate mass effect are drawn by using mat lab program. The results show that the adjusting the upper deck vibration isolation stiffness parameters has little effect on the amplitude of vibration power flow, increasing intermediate mass can move first peak to the low frequency, increasing intermediate mass can obviously reduce t transmitted power flow and transmitted vibration speed amplitude to the basement.

Low Frequency Vibration Isolation Through an Active-on-Active Approach: Coupling Effects

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Qiao Sun ◽  
Robert A. Wolkow ◽  
Mark Salomons
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Noise Cancellation ◽  
Frequency Noise ◽  
Active Stage ◽  
Coupling Effects ◽  
Active Approach ◽  
Low Frequency Vibration ◽  
Wide Range ◽  
Coupling Characteristics

The extreme sensitivity of a scanning probe microscope demands an exceptional noise cancellation device that could effectively cut off a wide range of vibration noise. Existing commercial devices, although excellent in canceling high frequency noise, commonly leave low frequency vibration unattenuated. We design an add-on active stage that can function together with a standalone existing active stage. The objective is to provide a higher level of noise cancellation by lowering the overall system cut-off frequency. This study is concerned with the theoretical aspects of the coupling characteristics involved in stacking independently designed stages together to form a two-stage isolator. Whether an add-on stage would pose a stability threat to the existing stage needs to be addressed. In addition, we explore the use of coupling effects to optimize the performance of the overall system.

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