scholarly journals Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenhua Yan ◽  
Bing Zhu ◽  
Xuefei Li ◽  
Guoqiang Wang
Keyword(s):  
Vibration Isolation ◽  
Characteristic Curve ◽  
Real Zero ◽  
Low Frequency ◽  
Static Characteristic ◽  
Static Characteristics ◽  
Weight Changes ◽  
Road Vehicles ◽  
Seat Suspension ◽  
Performance Reduction

Low-frequency vibrations (0.5–5 Hz) that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

Modelling and validation of a seat suspension with rubber spring for off-road vehicles

2017 ◽  
Vol 24 (18) ◽  
pp. 4110-4121 ◽  
Author(s):  
Leilei Zhao ◽  
Yuewei Yu ◽  
Changcheng Zhou ◽  
Fuxing Yang
Keyword(s):  
Vibration Isolation ◽  
Ride Comfort ◽  
Low Frequency ◽  
Model Parameters ◽  
Seat Suspension ◽  
System A ◽  
Low Frequency Vibration ◽  
New Type ◽  
Suspension Model ◽  
Better Than

To improve seat performance of low-frequency vibration isolation, this paper investigates a new type of seat suspension with a hollow composite rubber spring. To better describe the real system, a nonlinear suspension model was built. Then, the model parameters were identified and validated, the results show that the model is workable and the identified parameters are acceptable. The acceleration transmissibility of the new suspension was also analyzed by test and simulation. The resonant frequencies measured are close to the simulated under different excitation amplitudes, and all the relative deviations of the resonant frequency are less than 2.0%. Finally, in order to make clear how much the new suspension is better than the traditional suspension with the coil spring, the comparison of ride comfort was conducted under different working conditions. The results show that the new suspension can more effectively attenuate the low frequency from the uneven ground, meanwhile, it can provide a more stable support so that the driver can control the vehicle effectively. The model proposed can be used to predict the performance of the new seat suspension. The new suspension and the model provide a valuable reference for broadening the type of the seat suspension and exploring the optimal performance.

scholarly journals Tunable Low Frequency Band Gap and Waveguide of Phononic Crystal Plates with Different Filling Ratio

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang
Keyword(s):  
Band Gap ◽  
Composite Structure ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Filling Ratio ◽  
Height Ratio ◽  
Road Vehicles ◽  
Aluminum Base ◽  
Gap Width

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.

Design of an effective vibration isolation system for measurements sensitive to low-frequency vibrations

2012 ◽  
Vol 30 (6) ◽  
pp. 063201 ◽  
Author(s):  
Katsuya Iwaya ◽  
Ryota Shimizu ◽  
Akira Teramura ◽  
Seiji Sasaki ◽  
Toru Itagaki ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Isolation System ◽  
Vibration Isolation System

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.

On vibration isolation of sandwich plate with periodic hollow tube core

2017 ◽  
Vol 21 (3) ◽  
pp. 1119-1132 ◽  
Author(s):  
Gui-Lan Yu ◽  
Hong-Wei Miao
Keyword(s):  
Vibration Isolation ◽  
Sandwich Plate ◽  
Experimental Studies ◽  
Low Frequency ◽  
Dispersion Relations ◽  
Frequency Responses ◽  
Vibration Attenuation ◽  
Potential Applications ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolation performance of a PC sandwich plate with periodic hollow tube core is investigated experimentally and numerically. The experiment results reveal that there exist vibration attenuation zones in acceleration frequency responses which can be improved by increasing the number of periods or tuning some structure parameters. The presence of soft fillers shifts the attenuation zone to lower frequencies and enhances the capability of vibration isolation to some extent. Dispersion relations and acceleration frequency responses are calculated by finite element method using COMSOL MULTIPHYSICS. The attenuation zones obtained by experiments fit well with that by simulations, and both are consistent with the band gap in dispersion relations. The numerical and experimental studies in the present paper show that this PC sandwich plate exhibits a good performance on vibration isolation in low frequency ranges, which will provide some useful references for relevant research and potential applications in vibration propagation manipulations.

scholarly journals The active dynamic vibration damper in non-stationary operation of a vibroactive unit

2021 ◽  
pp. 13-17
Author(s):  
D. V. Sitnikov ◽  
◽  
A. A. Burian ◽  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Resonance Region ◽  
Frequency Region ◽  
Vibration Damper ◽  
Passive System ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Dynamic Vibration ◽  
Impulse Characteristics

The paper considers a vibration isolation system, in which a force is applied to the moving mass of the active dynamic vibration damper by an actuator in proportion to the measured value of the base response. The amplitude-frequency and impulse characteristics are plotted depending on the parameters of the system, assuming the actuator without distortion generates the force proportional to the base response. It is shown that the considered vibration isolation system is quite effective in the low-frequency region, including in the resonance region of the passive system, both in stationary and nonstationary modes of vibroactive forces

scholarly journals Identification and Removal of Non-acoustic Noise in Towed Array Sonar Using F-Κ Transform for Enhanced Torpedo Detection

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Vibration Isolation ◽  
Acoustic Noise ◽  
Detection System ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Noise Sources ◽  
Towed Array ◽  
Spatio Temporal ◽  
Towed Arrays

Low frequency passive towed array sonar is an essential component in a torpedo detection system for surface ships. Compact towed arrays are used for torpedo detection and they will be towed at higher towing speeds compared to conventional towed array sonars used for surveillance. Presence of non-acoustic noise in towed array sensors at higher towing speeds degrades torpedo detection capability at lower frequencies. High wavenumber mechanical vibrations are induced in the array by vortex shedding associated with hydrodynamic flow over the array body and cable scope. These vibrations are known to couple into the hydrophone array as nonacoustic noise sources and can impair acoustic detection performance, particularly in the forward end fire direction. Lengthy mechanical vibration isolation modules can isolate vibration induced noise in towed arrays, but this is not recommended in a towed array which is towed at high speeds as it will increase the drag and system complexity. An algorithm for decomposing acoustic and non-acoustic components of signals received at sensor level using well known frequency-wavenumber transform (F-K transform) is presented here. Frequency-wavenumber diagrams can be used for differentiating between acoustic and non-acoustic signals. An area of V shape is identified within the F-K spectrum where acoustic energy is confined. Energy outside this V will highlight non-acoustic energy. Enhanced simultaneous spatio-temporal and spatio-amplitude detection is possible with this algorithm. Performance of this algorithm is validated through simulation and experimental data.

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