scholarly journals Hybrid modelling of driver seat-cushion coupled system for metropolitan bus

2017 ◽  
Vol 36 (3) ◽  
pp. 214-226 ◽  
Author(s):  
Leilei Zhao ◽  
Changcheng Zhou ◽  
Yuewei Yu ◽  
Fuxing Yang
Keyword(s):  
Ride Comfort ◽  
Dynamic Properties ◽  
Complex Structure ◽  
Coupled System ◽  
Bench Test ◽  
Model Parameters ◽  
Specific Flow ◽  
Hybrid Modelling ◽  
Seat Suspension ◽  
Seat Cushion

For the complex structure of driver seat-cushion coupled system for metropolitan buses, there are still lack of convenient and reliable modelling methods for the system at present. To improve ride comfort, the coupled dynamic model is urgently needed to give insight into the dynamic properties of the coupled system. In this paper, for a standard commercially available seat fitted into metropolitan buses, the coupling between the seat and cushion, the nonlinear damping characteristics of the seat damper, and the elastic properties of the damper mounting bushings have been accounted for in a three degree-of-freedom driver seat-cushion coupled system model. Combing field measurements of the seat suspension excitation and cushion acceleration response, a specific flow of hybrid modelling of driver seat-cushion coupled system without the requirement of further bench tests was presented. The analogy between acceleration responses in the frequency domain and the time courses proves that the model can predict the dynamic characteristics of the coupled system with good accuracy for stationary random excitation. The model parameters were also validated by the corresponding bench test. The results show that the accuracy of the model parameters is sufficient and the hybrid modelling method is reliable, which provide a foundation for the optimal design of seat suspension and/or cushion to further improve ride comfort.

scholarly journals Nonlinear Model of the Passenger Car Seat Suspension System

2017 ◽  
Vol 67 (1) ◽  
pp. 23-28
Author(s):  
Ján Danko ◽  
Tomáš Milesich ◽  
Jozef Bucha
Keyword(s):  
Mathematical Model ◽  
Data Model ◽  
Ride Comfort ◽  
Suspension System ◽  
Model Parameters ◽  
Passenger Car ◽  
Car Seat ◽  
Seat Suspension ◽  
Force Velocity ◽  
Force Displacement

Abstract The paper deals with the modelling of a passenger car seat suspension system. Currently, vehicle safety and ride comfort are one of the most important factors of vehicle design. This article analyses a mathematical model of the passenger car seat suspension system. Furthermore, experimental measurements of the passenger car seat suspension system are performed. Utilizing the experimental data, model parameters are identified. From the chosen mathematical model a simulation model in constructed in Matlab is designed. In this simulation, the force-velocity and force-displacement characteristics of the passenger car seat suspension system are described. Finally, evaluation of simulated damper characteristics with the characteristics form measured data are performed.

scholarly journals Nonlinear Dynamic Modelling of a Suspension Seat for Predicting the Vertical Seat Transmissibility

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Weitan Yin ◽  
Juyue Ding ◽  
Yi Qiu
Keyword(s):  
Nonlinear Dynamic ◽  
Ride Comfort ◽  
Dynamic Modelling ◽  
Vertical Vibration ◽  
Lumped Parameter Model ◽  
Nonlinear Behaviour ◽  
Seat Suspension ◽  
Lumped Parameter ◽  
Seat Cushion ◽  
Inert Mass

Suspension seats are widely used in heavy vehicles to reduce vibration transmitted to human body and promote ride comfort. Previous studies have shown that the dynamics of the suspension seat exhibits nonlinear behaviour with changed vibration magnitudes. Despite various linear seat models developed in the past, a nonlinear model of the suspension seat capturing the nonlinear dynamic behaviour of the seat suspension and cushion has not been developed for the prediction of the seat transmissibility. This paper proposes a nonlinear lumped parameter model of the suspension seat to predict the nonlinear dynamic response of the seat. The suspension seat model comprises of a nonlinear suspension submodel integrated with a nonlinear cushion submodel. The parameters of the submodels are determined by minimizing the error between the simulated and the measured transmissibility of the suspension mechanism and the force-deflection curve of the seat cushion, respectively. The model of the complete seat is then validated using the seat transmissibility measured with inert mass under vertical vibration excitation. The results show that the proposed suspension seat model can be used to predict the seat transmissibility with various excitation magnitudes.

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.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

scholarly journals Study on Friction in Automotive Shock Absorbers Part 1: Friction Simulation Using a Dynamic Friction Model in the Contact Zone of an FEM Model

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 212-232
Author(s):  
Ludwig Herzog ◽  
Klaus Augsburg
Keyword(s):  
Ride Comfort ◽  
Viscous Friction ◽  
Simulation Method ◽  
Friction Model ◽  
Model Parameters ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Shock Absorbers ◽  
Operation Conditions ◽  
Wide Range

The important change in the transition from partial to high automation is that a vehicle can drive autonomously, without active human involvement. This fact increases the current requirements regarding ride comfort and dictates new challenges for automotive shock absorbers. There exist two common types of automotive shock absorber with two friction types: The intended viscous friction dissipates the chassis vibrations, while the unwanted solid body friction is generated by the rubbing of the damper’s seals and guides during actuation. The latter so-called static friction impairs ride comfort and demands appropriate friction modeling for the control of adaptive or active suspension systems. In this article, a simulation approach is introduced to model damper friction based on the most friction-relevant parameters. Since damper friction is highly dependent on geometry, which can vary widely, three-dimensional (3D) structural FEM is used to determine the deformations of the damper parts resulting from mounting and varying operation conditions. In the respective contact zones, a dynamic friction model is applied and parameterized based on the single friction point measurements. Subsequent to the parameterization of the overall friction model with geometry data, operation conditions, material properties and friction model parameters, single friction point simulations are performed, analyzed and validated against single friction point measurements. It is shown that this simulation method allows for friction prediction with high accuracy. Consequently, its application enables a wide range of parameters relevant to damper friction to be investigated with significantly increased development efficiency.

scholarly journals A Theoretical Model for the Transmission Dynamics of the Buruli Ulcer with Saturated Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ebenezer Bonyah ◽  
Isaac Dontwi ◽  
Farai Nyabadza
Keyword(s):  
Human Population ◽  
Reproduction Number ◽  
Buruli Ulcer ◽  
Coupled System ◽  
Model Parameters ◽  
The Public ◽  
Treatment Function ◽  
Medical Facilities ◽  
The Stability ◽  
Saturated Treatment

The management of the Buruli ulcer (BU) in Africa is often accompanied by limited resources, delays in treatment, and macilent capacity in medical facilities. These challenges limit the number of infected individuals that access medical facilities. While most of the mathematical models with treatment assume a treatment function proportional to the number of infected individuals, in settings with such limitations, this assumption may not be valid. To capture these challenges, a mathematical model of the Buruli ulcer with a saturated treatment function is developed and studied. The model is a coupled system of two submodels for the human population and the environment. We examine the stability of the submodels and carry out numerical simulations. The model analysis is carried out in terms of the reproduction number of the submodel of environmental dynamics. The dynamics of the human population submodel, are found to occur at the steady states of the submodel of environmental dynamics. Sensitivity analysis is carried out on the model parameters and it is observed that the BU epidemic is driven by the dynamics of the environment. The model suggests that more effort should be focused on environmental management. The paper is concluded by discussing the public implications of the results.

Kinematic Analysis and Simulation on Parallel Vibration Reduction Seat

2011 ◽  
Vol 464 ◽  
pp. 195-198
Author(s):  
Qi Zhi Yang ◽  
Guo Quan Huang ◽  
Chen Long ◽  
Xiao Bing Zhu
Keyword(s):  
Ride Comfort ◽  
Vibration Reduction ◽  
Simulation Models ◽  
Vibration System ◽  
Good Effort ◽  
Seat Suspension ◽  
Vehicle System ◽  
Adams Software ◽  
Seat Vibration ◽  
Vehicle Seat

Vibration of vehicle system is a typical vibration of multi-degree freedom. The damping performance of multi-degree freedom seat suspension is important to ride comfort of vehicle occupants. Based on the multi-dimensional movement principle of parallel mechanism, it is built a new vehicle seat with 3-DOF suspension. It is Established a kinematics model and then analyzed the theory of the displacement of the parallel vehicle seat system. Finally, using ADAMS software to build the simulation models of seat suspension, it is showed that the seat vibration system has a good effort on vibration reduction.

Identification of ’Effective’ Linear Joints Using Coupling and Joint Identification Techniques

1998 ◽  
Vol 120 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Y. Ren ◽  
C. F. Beards
Keyword(s):  
Dynamic Properties ◽  
Real Life ◽  
Model Parameters ◽  
Coupling Technique ◽  
Alternative Approach ◽  
Identification Technique ◽  
Joint Identification ◽  
Stiff Joint ◽  
Almost All ◽  
Identification Techniques

Almost all real-life structures are assembled from components connected by various types of joints. Unlike many other parts, the dynamic properties of a joint are difficult to model analytically. An alternative approach for establishing a theoretical model of a joint is to extract the model parameters from experimental data using joint identification techniques. The accuracy of the identification is significantly affected by the properties of the joints themselves. If a joint is stiff, its properties are often difficult to identify accurately. This is because the responses at both ends of the joint are linearly-dependent. To make things worse, the existence of a stiff joint can also affect the accuracy of identification of other effective joints (the term “effective joints” in this paper refers to those joints which otherwise can be identified accurately). This problem is tackled by coupling these stiff joints using a generalized coupling technique, and then the properties of the remaining joints are identified using a joint identification technique. The accuracy of the joint identification can usually be improved by using this approach. Both numerically simulated and experimental results are presented.

scholarly journals Ride Comfort Control System Considering Physiological and Psychological Characteristics: Effect of Masking on Vertical Vibration on Passengers

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 42 ◽  
Author(s):  
Keigo Ikeda ◽  
Ayato Endo ◽  
Ryosuke Minowa ◽  
Takayoshi Narita ◽  
Hideaki Kato
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Ride Comfort ◽  
Control Method ◽  
Vertical Vibration ◽  
Psychological Characteristics ◽  
Psychological State ◽  
Vibration Acceleration ◽  
Seat Suspension ◽  
Vibration Stress

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method.

scholarly journals Mechanical aspects of the semicircular ducts in the vestibular system

2020 ◽  
Vol 114 (4-5) ◽  
pp. 421-442
Author(s):  
Mees Muller
Keyword(s):  
Brownian Motion ◽  
Vestibular System ◽  
Equations Of Motion ◽  
Complex Structure ◽  
Coupled System ◽  
Continuity Equations ◽  
Mathematical Expressions ◽  
Semicircular Ducts ◽  
Evolutionary Aspects ◽  
Instrumental Role

Abstract The semicircular ducts (SCDs) of the vestibular system play an instrumental role in equilibration and rotation perception of vertebrates. The present paper is a review of quantitative approaches and shows how SCDs function. It consists of three parts. First, the biophysical mechanisms of an SCD system composed of three mutually connected ducts, allowing endolymph to flow from one duct into another one, are analysed. The flow is quantified by solving the continuity equations in conjunction with the equations of motion of the SCD hydrodynamics. This leads to mathematical expressions that are suitable for further analytical and numerical analysis. Second, analytical solutions are derived through four simplifying steps while keeping the essentials of the coupled system intact. Some examples of flow distributions for different rotations are given. Third, the focus is on the transducer function of the SCDs. The complex structure of the mechano-electrical transduction apparatus inside the ampullae is described, and the consequences for sensitivity and frequency response are evaluated. Furthermore, both the contributions of the different terms of the equations of motion and the influence of Brownian motion are analysed. Finally, size limitations, allometry and evolutionary aspects are taken into account.

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