Application of phononic crystals for vibration reduction and noise reduction of wheel-driven electric buses based on neural networks

Author(s):  
Boqiang Zhang ◽  
Penghui Chen ◽  
Huiyong Chen ◽  
Tianpei Feng ◽  
Chengxin Cai ◽  
...  

Because of the position of the motor and the excitation of the suspension system, a wheel-driven electric bus produces low-frequency noise, which is difficult to resolve through traditional sound absorption and noise reduction technology. Through an interior noise test of a wheel-driven electric bus, we found that the interior low-frequency noise had a considerable influence on the driver. In order to solve this problem, a locally resonant phononic crystal was used to meet the requirements of vibration and noise reduction for the wheel-driven electric bus. The intrinsic relationship between the band gap distribution of the locally resonant phononic crystal and the topology was established by training a neural network, so as to achieve the desired effect of the bandgap model on the basis of the input bandgap range. Upon an increase in the number of models, the prediction model error decreased gradually. This method could quickly obtain the structural parameters of the locally resonant phononic crystal with the expected band gap, which made it convenient to apply locally resonant phononic crystals to the vibration and noise reduction of wheel-driven electric buses and in other fields.

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 995
Author(s):  
Chuanmin Chen ◽  
Zhaofeng Guo ◽  
Songtao Liu ◽  
Hongda Feng ◽  
Chuanxi Qiao

Localized resonance phononic crystals (LRPCs) are increasingly attracting scientists’ attention in the field of low-frequency noise reduction because of the excellent subwavelength band gap characteristics in the low-frequency band. However, the LRPCs have always had the disadvantage that the noise reduction band is too narrow. In this paper, in order to solve this problem, LRPCs based on double-layer plates with cavity structures are designed. First, the energy bands of phononic crystals plate with different thicknesses were calculated by the finite element method (FEM). At the same time, the mechanism of band gap generation was analyzed in combination with the modalities. Additionally, the influence of structure on the sound transmission loss (STL) of the phononic crystals plate and the phononic crystals cavity plates were analyzed, which indicates that the phononic crystals cavity plates have notable characteristics and advantages. Moreover, this study reveals a unique ”cavity cave” pattern in the STL diagram for the phononic crystals cavity plates, and it was analyzed. Finally, the influence of structural factors on the band structure and STL of phononic crystals cavity plates are summarized, and the theoretical basis and method guidance for the study of phononic crystals cavity plates are provided. New ideas are also provided for the future design and research of phononic crystals plate along with potential applications in low-frequency noise reduction.


Author(s):  
Li Shen ◽  
Jiu Hui Wu

Phononic crystal is an artificial periodic structure in which elastic constants distribute periodically. In this paper, a two dimensional Bragg scattering phononic crystal was introduced into low-frequency noise reduction facility in the brake originally. Through the theoretical analysis by using Plane-wave Expansion Method to obtain the band diagram of a phononic crystal with holes periodically arranged in the 45 carbon steel plate and establishing the equivalent model in motion as the brake, we find an approximate bandgap between 0–5400Hz in the low-frequency range while the complete static bandgaps are distributed in the high-frequency range. It is believed that this kind of extremely low-frequency bandgap is due to the combination of the vibration of a single scatter and the interaction among scatters. In order to demonstrate the theory, contrastive experiment was taken. Noise spectrum diagram of the origin plate without holes was obtained in the first experiment. According to the equivalent model, the two dimensional air column/steel matrix phononic crystal structure in which filling rate was 40% was designed to apply in the test apparatus so that the frequency range (2050 to 2300Hz) of strong noise would be involved in this bandgap. Moreover, the noise in the whole frequency range (0–2550Hz) went down. This phenomenon proved that experiment result was coincident with theoretic consequence. The maximum decreasing amplitude of the noise reached as much as 25dB and the average decreasing amplitude was about 13dB from 2050 to 2300 Hz. In a word, this bandgap which is the combination effect of structure periodicity or the Mie scattering has an obvious extremely low-frequency characteristic in noise and vibration control in the brake.


2011 ◽  
Vol 299-300 ◽  
pp. 1208-1211
Author(s):  
Yu Yang He ◽  
Xiao Xiong Jin ◽  
Huan Wei

Automotive low frequency noise is difficult to control in a traditional way. Locally resonant phononic crystals (PCs) can forbid the propagation of certain frequency. This PCs’ structure also can be fabricated to apply in automotive noise control. The simulation method is applied to establish the model of two-dimensional (2D) locally resonant phononic crystals in order to research the impact of the parameters on the propagation. The band gap of locally resonant phononic crystals in z mode is calculated using the simplified model.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang

Aiming at solving the NVH problem in vehicles, a novel composite structure is proposed. The new structure uses a hollow-stub phononic-crystal with filled cylinders (HPFC) plate. Any unit in the plate consists of a lead head, a silicon rubber body, an aluminum base as outer column and an opposite arranged inner pole. The dispersion curves are investigated by numerical simulations and the influences of structural parameters are discussed, including traditional hollow radius, thickness, height ratio, and the new proposed filling ratio. Three new arrays are created and their spectrum maps are calculated. In the dispersion simulation results, new branches are observed. The new branches would move towards lower frequency zone and the band gap width enlarges as the filling ratio decreases. The transmission spectrum results show that the new design can realize three different multiplexing arrays for waveguides and also extend the locally resonant sonic band gap. In summary, the proposed HPFC structure could meet the requirement for noise guiding and filtering. Compared to a traditional phononic crystal plate, this new composite structure may be more suitable for noise reduction in rail or road vehicles.


1967 ◽  
Vol 42 (5) ◽  
pp. 1202-1203
Author(s):  
J. Ronald Bailey ◽  
Franklin D. Hart

2015 ◽  
Vol 63 (1) ◽  
pp. 20-35 ◽  
Author(s):  
Dong Guan ◽  
Jiu Hui Wu ◽  
Li Jing ◽  
Nansha Gao ◽  
Mingming Hou

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