scholarly journals Analysis and Optimization of Low-Speed Road Noise in Electric Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wentao Yu
Keyword(s):  
Working Condition ◽  
Dynamic Vibration Absorber ◽  
Modal Frequency ◽  
Vehicle Noise ◽  
The Road ◽  
Acoustic Cavity ◽  
Asphalt Road ◽  
Road Excitation ◽  
Noise Vibration ◽  
Pressure Sensation

When a certain electric vehicle is driving at a constant speed of 40 km/h on the rough asphalt road, the rear passenger can obviously feel the ear pressure, which seriously affects the comfort. Through the analysis of objective data, it was found that the problem was caused by the road excitation, which leads to the coupling between the mode of the backup door and the mode of the acoustic cavity, and causes the resonance of the car cavity, thus causing the ear pressure sensation. To solve this problem, this paper optimizes the backup door by means of experiment and simulation, increases the dynamic vibration absorber, makes its modal frequency avoid the acoustic cavity modal frequency, and achieves the purpose of reducing the interior noise. After optimization, the vehicle noise is reduced by 8 dBA at 42 Hz under 40 km/h working condition of rough road surface, and the ear pressure sensation is reduced at the same time, thus improving the NVH (noise, vibration, and harshness) performance of the vehicle.

scholarly journals Smartphone monitoring of in-ambulance vibration and noise

2021 ◽  
pp. 095441192098599
Author(s):  
Tom Partridge ◽  
Lorelei Gherman ◽  
David Morris ◽  
Roger Light ◽  
Andrew Leslie ◽  
...  
Keyword(s):  
Transport Systems ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Noise Levels ◽  
The Road ◽  
Neonatal Transport ◽  
Mass Data ◽  
Transport Team ◽  
Vertical Accelerations ◽  
Noise Vibration

Transferring sick premature infants between hospitals increases the risk of severe brain injury, potentially linked to the excessive exposure to noise, vibration and driving-related accelerations. One method of reducing these levels may be to travel along smoother and quieter roads at an optimal speed, however this requires mass data on the effect of roads on the environment within ambulances. An app for the Android operating system has been developed for the purpose of recording vibration, noise levels, location and speed data during ambulance journeys. Smartphone accelerometers were calibrated using sinusoidal excitation and the microphones using calibrated pink noise. Four smartphones were provided to the local neonatal transport team and mounted on their neonatal transport systems to collect data. Repeatability of app recordings was assessed by comparing 37 journeys, made during the study period, along an 8.5 km single carriageway. The smartphones were found to have an accelerometer accurate to 5% up to 55 Hz and microphone accurate to 0.8 dB up to 80 dB. Use of the app was readily adopted by the neonatal transport team, recording more than 97,000 km of journeys in 1 year. To enable comparison between journeys, the 8.5 km route was split into 10 m segments. Interquartile ranges for vehicle speed, vertical acceleration and maximum noise level were consistent across all segments (within 0.99 m . s−1, 0.13 m · s−2 and 1.4 dB, respectively). Vertical accelerations registered were representative of the road surface. Noise levels correlated with vehicle speed. Android smartphones are a viable method of accurate mass data collection for this application. We now propose to utilise this approach to reduce potential harmful exposure, from vibration and noise, by routing ambulances along the most comfortable roads.

scholarly journals Recent progress in battery electric vehicle noise, vibration, and harshness

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042110052
Author(s):  
Xia Hua ◽  
Alan Thomas ◽  
Kurt Shultis
Keyword(s):  
Electric Vehicle ◽  
Recent Progress ◽  
Combustion Engine ◽  
Automatic Transmission ◽  
Battery Electric Vehicle ◽  
Vehicle Noise ◽  
Conventional Vehicle ◽  
Transfer Case ◽  
Air Intake ◽  
Noise Vibration

As battery electric vehicle (BEV) market share grows so must our understanding of the noise, vibration, and harshness (NVH) phenomenon found inside the BEVs which makes this technological revolution possible. Similar to the conventional vehicle having encountered numerous NVH issues until today, BEV has to face many new and tough NVH issues. For example, conventional vehicles are powered by the internal combustion engine (ICE) which is the dominant noise source. The noises from other sources were generally masked by the combustion engine, thus the research focus was on the reduction of combustion engine while less attention was paid to noises from other sources. A BEV does not have ICE, automatic transmission, transfer case, fuel tank, air intake, or exhaust systems. In their place, there is more than enough space to accommodate the electric drive unit and battery pack. BEV is quieter without a combustion engine, however, the research on vehicle NVH is even more significant since the elimination of the combustion engine would expose many noise behaviors of BEV that were previously ignored but would now seem clearly audible and annoying. Researches have recently been conducted on the NVH of BEV mainly emphasis on the reduction of noise induced by powertrain, tire, wind and ancillary system and the improvement of sound quality. This review paper will focus on recent progress in BEV NVH research to advance the BEV systems in the future. It is a review for theoretical, computational, and experimental work conducted by both academia and industry in the past few years.

scholarly journals EVALUATING THE TRIGGERING FACTORS OF THE ROCK FALLS OF 16TH AND 21ST DECEMBER 2009 IN NEA FOKEA, CHALKIDIKI, NORTHERN GREECE

2017 ◽  
Vol 43 (3) ◽  
pp. 1131
Author(s):  
B. Christaras ◽  
G. Syrides ◽  
G. Papathanassiou ◽  
A. Chatzipetros ◽  
T. Mavromatis ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Slope Instability ◽  
Rock Falls ◽  
Northern Greece ◽  
Local Authorities ◽  
Protective Measures ◽  
The Road ◽  
Triggering Factors ◽  
Country Road ◽  
Asphalt Road

This paper aims to present the characteristics of the rock falls generated on the 16th and 21st of December 2009 at the Nea Moudania – Kassandria country road in Kassandra Peninsula, Chalkidiki, Greece. Both of those events induced damages to the asphalt road and forced the local authorities to close the road to traffic until the construction of protective measures. In order to evaluate the rock fall hazard and analyze the slope instability in the area, the present study focuses on three main triggering factors: rainfall, stratigraphy and tectonic setting.

scholarly journals Attenuation of Motorcycle Handle Vibration Using Dynamic Vibration Absorber

2018 ◽  
Vol 217 ◽  
pp. 01006
Author(s):  
Muhammad Iyad Al-Maliki Saifudin ◽  
Nabil Mohamad Usamah ◽  
Zaidi Mohd Ripin
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Additional Source ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
The Road ◽  
Dynamic Vibration ◽  
Attenuation Level ◽  
Road Surface Roughness ◽  
Extended Exposure

Motorcycle riders are exposed to hand-transmitted vibration of the hand-arm system due to the vibration of the handle and extended exposure can result in numbness and trembling. One feasible solution to attenuate the handle vibration is by using a dynamic vibration absorber (DVA). In this work a DVA is designed and mounted on the motorcycle handle in order to reduce the vibration at the handle by transferring the vibration from the primary system handle to the secondary mass. Removal of elastomeric material at the DVA mounting locations, symmetry of secondary mass and the direction of DVA attachment influence the vibration absorption. A series of tests conducted show that the vibration on the handle is mainly induced by the engine and there is additional source of vibration from the road surface roughness. Installation of DVA at different locations on the handle resulted in various attenuation levels at different speed in the x and z directions. the attenuation level is between 59-68 % in the biodynamic x-directions for speed at 30-50 kmh-1.

Study on Control Strategies of Semi-Active Air Suspension for Heavy Vehicles Based on Road-Friendliness

2012 ◽  
Vol 452-453 ◽  
pp. 328-333
Author(s):  
Feng He ◽  
Jing Zhao ◽  
Hao Yu Wang
Keyword(s):  
Pid Controller ◽  
Fuzzy Controller ◽  
Control Strategies ◽  
Fuzzy Pid ◽  
Control Effect ◽  
The Road ◽  
Fuzzy Pid Controller ◽  
Air Suspension ◽  
Road Excitation ◽  
Band Limited

Targeting the road-friendliness of vehicles, the paper has analyzed dynamic deformation and dynamic load of tires under different control strategies through co-simulation. A vehicle dynamics model with semi-active air suspension has been made through using Adams, and a PID controller, a fuzzy controller and a fuzzy PID controller have been set in the Matlab to adjust the damping of the suspension, with the road excitation modeled through band-limited white noise. The result shows that the fuzzy PID controller has overcome the shortcomings of the PID controller and the fuzzy controller and a better control effect has been achieved.

Analysis of sound radiation from the coupling effect of vibrating noise and moving-vehicle noise on bridges

2005 ◽  
Vol 32 (5) ◽  
pp. 881-898 ◽  
Author(s):  
Yong-Seon Lee ◽  
Sang-Hyo Kim ◽  
Won-Suk Jang
Keyword(s):  
Dynamic Response ◽  
Noise Level ◽  
Acoustic Pressure ◽  
Sound Radiation ◽  
Element Model ◽  
Frequency Noise ◽  
Vehicle Noise ◽  
The Road ◽  
Vehicle Weight ◽  
Vibration Noise

An acoustic finite element model of a bridge is developed to evaluate the noise generated by the traffic-induced vibration of the bridge. The dynamic response of a multi-girder bridge, modeled by a three-dimensional (3-D) frame element model, is analyzed with a 3-axle (8 degrees of freedom (DOF)) truck model and a 5-axle (13 DOF) tractor-trailer. The flat plate element is used to analyze the acoustic pressure due to the fluid–structure interactions between the vibrating surface and contiguous acoustic fluid medium. The radiation fields of noise with a specified distribution of vibrating velocity and pressure on the structural surface are also computed using the Kirchhoff–Helmholtz integral. Among the diverse parameters affecting the dynamic response of a bridge, vehicle velocity, vehicle weight, and spatial distribution of the road surface roughness are found to be the main factors that increase the level of vibration noise. In an attempt to illustrate the influence of the structural vibration noise of a bridge to total noise level around the bridge, the random function is used to generate the vehicle noise source including the engine noise and the rolling noise between the road and tire. The results show that the low-frequency noise produced by the vibrating bridge members amplifies the high-frequency vehicle noise by 4–7 dB. In addition, the amplification rate of noise increases with traveling speed and vehicle weight. Key words: acoustic pressure on surface, sound radiation, noise level, Kirchhoff–Helmholtz integrals, dynamic response, vehicle noise model, sound pressure level.

scholarly journals Perceiving Excitation Characteristics from Interactions between Field Road and Vehicle via Vibration Sensing

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yuansheng Cheng ◽  
Xiaoqin Li ◽  
Xiaolan Man ◽  
Feifan Fan ◽  
Zhixiong Li
Keyword(s):  
Vibration Response ◽  
Road Surface ◽  
Vibration Test ◽  
Agricultural Vehicles ◽  
The Road ◽  
Effective Roughness ◽  
Long Wave ◽  
Road Surfaces ◽  
Road Excitation ◽  
Wave Surfaces

When agricultural vehicles operate in the field, the soft road excitation makes it difficult to measure the vehicle vibration. A camera-accelerator system can solve this issue by utilizing computer vision information; however, the relationship between the field road surface and the vehicle vibration response remains an unsolved problem. This study aims to investigate the correlation of the soft road excitation of different long-wave surfaces with the vehicle vibration response. Vibration equation between the vehicle and soft road surface system was established to produce an effective roughness model of the field soft road surface. In order to simulate the vehicle vibration state under different long-wave road surfaces, the soil rectangular pits with 21 kinds of different spans and depths were applied to the road surfaces, and a tractor vibration test system was built for vibration test. The frequency spectrum analysis was performed for the vibration response and the roughness signals of the road surfaces. The results showed that coefficient (R2) of frequency correlation between the roughness excitation and the original unevenness at the excitation point at the rear end of the rectangular soil pit fell within 0.9641∼0.9969. The main frequency band of the vibration response fell within 0∼3 Hz, and the phenomenon of quadruple frequency existed. The correlation of roughness excitation with quadruple frequency fell within 0.992165∼1. The primary excitation points were located at the rear end of the rectangular soil pit. In addition, it also indicated that when the vehicle was driven without autonomous power, the vehicle vibration frequency mainly depended on the excitation frequency of the field road surface and the frequency at the maximum vehicle vibration intensity was 2 or 3 times of that at the maximum field soft road excitation. These findings may provide a reference for optimal design of vibration reduction and control for agricultural vehicles.

scholarly journals Entropy Based Classification of Road-Profiles

2010 ◽  
Author(s):  
S. C¸ag˘lar Bas¸lamıs¸lı ◽  
Selis O¨nel
Keyword(s):  
Nonlinear Damping ◽  
Operating Parameters ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Mean Square ◽  
The Road ◽  
Dirt Road ◽  
Asphalt Road ◽  
Acceleration Signals

In this study, the Shannon entropies of six different road-profiles ranging from “very good asphalt road” to “dirt road (terrain)” were calculated. Results indicate that each type of road has a well defined entropy value and that the entropies of roads ranging from “very good asphalt” to “dirt road (terrain)” lie on a nearly linear locus. A second approach presented in this paper consists in measuring the sprung mass vertical acceleration of a vehicle running over segments of roads of different qualities and calculating the entropies of the acceleration signals. This procedure has been applied to assess the influence of nonlinear damping and vehicle speed. It has been seen that it is possible to identify the type of the road surface through the calculation of entropy if the vehicle operating parameters are known. Finally, it is observed that the locus of entropy values is concave on the plot of acceleration entropy versus root mean square (RMS) acceleration.

Door sealing mechanism and process in vehicle engineering

2021 ◽  
pp. 095440702110598
Author(s):  
Menghan Tong ◽  
Shichao Xiu ◽  
Xiaoshan Chen ◽  
Siyu Chen
Keyword(s):  
Failure Time ◽  
Base Material ◽  
Rolling Process ◽  
Dynamics Simulation ◽  
Vehicle Engineering ◽  
Time Curve ◽  
Vehicle Noise ◽  
Rolling Pressure ◽  
Factors Influencing ◽  
Noise Vibration

The reliability of door sealing plays an important role in maintaining the quality of vehicle noise, vibration, and harshness (NVH). To improve the reliability of door sealing, a novel sealing process has been proposed. The factors influencing the door sealing quality have been investigated. The relationships between the peeling force, peeling speed, and peeling time have been calculated using the five-variable rheological theory. The maximum stress versus time curve and the distribution of stress and strain at the moment of debonding have been obtained by nonlinear solid cohesive coupling dynamics simulation. The rolling process of the door sealing strip has been developed, and automatic rolling equipment for door sealing has been designed and manufactured. The factors influencing the peeling force have been determined by a peeling test of the door sealing strip. The results show that the peeling force increases with an increase in the peeling speed and time. The C-shaped structure at the front end of the base material during the stripping process makes the peeling angle sharp. In addition, the uneven stripping speed causes the stripping line to become irregular. The peeling force increases with the increase in rolling pressure and failure time. The optimum rolling pressure was 70 N/m2 and the optimum aging time was 24 h.

Simulation Study of Heavy Vehicle Road-Friendliness under Bilateral Tracks’ Excitation

2013 ◽  
Vol 680 ◽  
pp. 422-428
Author(s):  
Da Wei Liu ◽  
Rong Chao Jiang ◽  
Yue Dong Yang ◽  
Song Wang
Keyword(s):  
Spectral Density ◽  
Fourth Power ◽  
Heavy Vehicle ◽  
Superposition Method ◽  
Heavy Vehicles ◽  
Driving Dynamic ◽  
Flexible Coupling ◽  
The Road ◽  
Power Spectral ◽  
Road Excitation

In order to study the road friendliness of heavy vehicle under bilateral tracks’ excitation, the spatial domain random pavement under bilateral tracks’ excitation was simulated through the second-order rational function power spectral density (PSD) and the harmonic superposition method. A rigid-flexible coupling virtual prototype of the heavy vehicle was established by using SIMPACK software. Then a driving dynamic model of heavy vehicle was established under bilateral tracks’ excitation. The tires loads of the vehicle’s each axle were calculated. The dynamic load coefficient (DLC) and 95 percentage fourth power aggregate force were used as the road-friendliness criterions for studying the road-friendliness of heavy vehicles under bilateral tracks’ road excitation. The research results could provide the basis for the prediction of road friendliness of heavy vehicle.

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