Performance Evaluation of the Vehicle Vibration Safety in the Frequency Domain

2018 ◽  
pp. 1-21 ◽  
Author(s):  
L. F. Zheglov ◽  
A. B. Fominykh
Keyword(s):  
Dynamical System ◽  
Mathematical Modelling ◽  
Frequency Domain ◽  
Vibration Isolation ◽  
Statistical Linearization ◽  
Safety Criterion ◽  
Isolation System ◽  
Time Domains ◽  
The Impact ◽  
Disturbing Action

The article deals with mathematical modelling of the nonlinear system of vehicle vibration isolation. It is known that this problem can be solved both in the frequency and in the time domains. To assess the adequacy of the results obtained, a computation algorithm for evaluated performances in the frequency domain is considered at the first stage of the study. In this case, a statistical linearization procedure is used through the example of a spatial dynamic model equivalent to the primary and secondary vibration isolation systems of a two-axle vehicle (a dynamical system with seventeen degrees of freedom). A matrix method for determining the frequency characteristics of a given dynamical system is used, and the adaptation features of four known methods of statistical linearization are shown. The article focuses attention on advantages of the system frequency representation when testing it and determining the main parameters. In order to generalize the conclusions when comparing the calculation results in the frequency and time domains, computations were performed for two variations of the intensity of the disturbing action. Such a "hard-line" approach enables us to determine the impact of the nonlinear characteristics of the vibration isolation system components on the output integral and separate-frequency performance estimates, taking into account a vehicle's safety criterion.The simulation results of this system show different values of the integral and separate-frequency estimates for all four methods of statistical linearization, regardless of the intensity of disturbing action and the loss probability of contact between the tire and the wearing surface from 5% to 30%. The calculation data obtained allow comparing with the mathematical modelling results of the given dynamical system in the time domain and defining position according to recommendation of the statistical linearization method.

scholarly journals Vibration Isolation of Existing Buildings in Microvibration Traffic Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Qian Xia ◽  
Wen-jun Qu ◽  
Yi-qing Li ◽  
Jin Zhao
Keyword(s):  
Vibration Isolation ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Isolation Effect ◽  
Slab Thickness ◽  
Filling Material ◽  
Construction Technology ◽  
Existing Buildings ◽  
Isolation System ◽  
The Impact

In order to explore the impact of traffic environmental microvibration on buildings, this paper studies indoor vibration isolation, a method applicable to existing buildings. The vibration isolation scheme is designed based on the residential buildings adjacent to metro lines in Shanghai. By using the dynamic theory, the effective range of vibration isolation stiffness is analyzed. The effectiveness of the indoor vibration isolation method is verified through theoretical calculations and comparison of field measurements before and after isolation. A detailed numerical model is established to analyze the indoor isolation and the effect after parameter optimization from the slab thickness, filling material, and isolator stiffness. The results show that the isolation effect is proportional to the thickness of the total slab thickness of the isolation system and inversely proportional to the stiffness of the isolator. And when concrete is used as the filling material, the isolation effect is best. The isolation effect of the midspan position is better than that of the wall-floor junction. The vibration isolation effect is more obvious after the parameters are optimized. With its convenient construction technology, short cycle, and low cost, this method is worth promoting.

Optimal Controller for Active Vehicle Suspension Disturbed by Sinusoidal Signals

2016 ◽  
Vol 248 ◽  
pp. 127-134
Author(s):  
Marek Sibielak ◽  
Waldemar Rączka ◽  
Jarosław Konieczny ◽  
Janusz Kowal
Keyword(s):  
Performance Index ◽  
Vibration Isolation ◽  
Optimal Solution ◽  
Vehicle Suspension ◽  
Isolation System ◽  
Control Laws ◽  
Control Time ◽  
Sinusoidal Signals ◽  
System Frequency ◽  
The Impact

The problem of optimal control of systems disturbed by sinusoidal signals for infinite control time is considered in the paper. The control laws described in [1] is base of a modified mean-square performance index with an infinite control time. The performance index was formulated in such a way that each sinusoidal component corresponds to a separate weight matrix. This allows energy constraints on the control signals to be differentiated based on frequency. An optimal solution to the optimization problem was found. In the paper the problem of the impact of time on the identification of sinusoidal disturbance on vibration isolation system frequency characteristic. The controller was synthesized for slow-active vehicle suspension [2,3]. The model of suspension, synthesis of the controller and implementation of the system was described. The results of simulations of the designed vehicle active suspension system are presented.

A Vibration Study of a Hydraulically-Actuated Legged Machine

2010 ◽  
Author(s):  
Emanuele Guglielmino ◽  
Ferdinando Cannella ◽  
Claudio Semini ◽  
Darwin G. Caldwell ◽  
Nestor Eduardo Nava Rodri´guez ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Legged Robot ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Hydraulically Actuated ◽  
Modes Of Vibration ◽  
Pros And Cons ◽  
Heavy Loads ◽  
Multi Body ◽  
The Impact

This paper presents a study on the impact of the vibration on a hydraulically-actuated legged robot designed for outdoor operations. The choice of using hydraulic actuation in lieu of electric actuation as is common in robotics has been driven by the need to cope with heavy loads and respond swiftly to external inputs and disturbances. However in such machines hydraulically-induced vibration (fluid borne noise and structure borne noise) is a major issue. Volumetric pumpmotor assembly is a primary cause of vibration. These are transmitted to the robotic structure, which has been designed as light as possible to minimise the robot’s total weight and power consumption and make it more agile. Initially a multi-body analysis of the robot was carried out to select an appropriate vibration isolation system. Subsequently a numerical and experimental modal analysis was carried out on the structure. The latter was carried with modal hammer tests and pump running tests. This has allowed identifying the main modes of vibration of the structure. The pros and cons of this approach are described and areas of improvements identified.

scholarly journals The Choice of Evaluation Vibration Car Security

2019 ◽  
pp. 1-14
Author(s):  
L. F. Zheglov ◽  
A. B. Fominykh
Keyword(s):  
Dynamic System ◽  
Frequency Domain ◽  
Time Domain ◽  
Vibration Isolation ◽  
Frequency Characteristics ◽  
Road Surface ◽  
Statistical Linearization ◽  
Support Surface ◽  
Dirt Road ◽  
The Time Domain

In the presented material of the article the debatable question - a question of a choice of the field of mathematical modeling of system of vibration isolation of the car is considered. It is known that such a problem can be solved in the frequency and time domain. Since the primary vibration isolation system of the car has non-linear elements, the question arises: how does the solution of the linearized dynamic system in the frequency domain correspond to the data of calculations of the accepted indicators in the time domain? The problem is solved with a random kinematic perturbation from the road surface. Therefore, when working in the time domain, it is necessary to pre-select the method of statistical linearization from the known in practice design of automatic control systems.Four methods of statistical linearization, using which calculations were carried out in the frequency domain, are considered. For a similar dynamic system with its initial and statistically linearized nonlinear elements, calculations were carried out in the time domain. It is shown that the first method of statistical linearization is the most adaptive, according to the amplitude-frequency characteristics of the system. Such calculations were carried out for two surfaces corresponding to the cobblestone and dirt road at different speeds of the car.The analysis of the calculated amplitude-frequency characteristics was carried out for the "resonant" speed of motion, at which the greatest manifestation of the system nonlinearity takes place. When driving in this mode, the system significantly increases the probability of losing contact with the tire support surface. This violates the safety of the vehicle and the system is out of the vibration safety analysis area. Especially this phenomenon is observed when driving on a dirt road at a "resonant" speed. The final results of the calculations are separate-frequency and integral parameters. The latter do not give priority in the selection of the area of calculation, provided the safety of the vehicle.Thus, it can be concluded that the adequacy of the calculations in the frequency and time domain under really specified conditions of the vehicle on the corresponding road surface. However, testing of the problem to be solved, for example, by the eigenfrequency vector of a conservative system, is advisable to be carried out in the frequency domain.

STUDY OF THE VIBRATION ISOLATION SYSTEM OF MARINE POWER PLANTS WITH A 5AL 25/30 DIESEL DRIVE

Akustika ◽  
2021 ◽  
pp. 112
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Kyaw Thet Naing
Keyword(s):  
Experimental Study ◽  
Diesel Engine ◽  
Power Plants ◽  
Vibration Isolation ◽  
Field Studies ◽  
Absorption System ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
The Impact

The article is devoted to the study of the support and side stop vibration isolation system of two marine power plants DGA- 500 with a 5AL 25/30 drive diesel engine, in which a hypothesis is put forward about the imperfection of the shock absorption system. The purpose of the research is to substantiate the imperfection of the support and side stop vibration isolation system of marine power plants with a 5 AL 25/30 drive diesel engine. The confirmation of this hypothesis and the achievement of this goal is justified on the basis of presentation of the results of field studies on the project’s courts B437/11 and the personal presence during the preparation of DGA-500 to repair at the shipyard. For the use of unbalanced engines as a drive for ship power plants, the authors, on the basis of a full-scale experimental study and analysis of known works, recommend initially assessing the possibility and purpose of depreciation of the unit according to the Katz unbalance criterion [1]. The objective of fixing the unit with diesel 5AL 25/30 on the criterion of imbalance Katz is soundproof, and the calculation of depreciation should be based on the impact of side stop vibration isolators. A significant improvement is recommended to the support 36-40 and side stop 41-52 vibration isolation system, elastic pipe fittings 8, support frame 2 and turbocharger bracket 4 (Fig. 1).

The Research of Semi-Active Fuzzy Control on Sweep Frequency Vibration of Geophysical Prospecting Car

2011 ◽  
Vol 105-107 ◽  
pp. 640-646
Author(s):  
Mi Liu ◽  
Guo An Yang ◽  
Yong Lin Zhao
Keyword(s):  
Control System ◽  
Fuzzy Control ◽  
Vibration Isolation ◽  
Vibration Signal ◽  
The Body ◽  
Geophysical Prospecting ◽  
Air Spring ◽  
Isolation System ◽  
Passive Vibration Isolation ◽  
The Impact

The vibration system of a geophysical prospecting car has three main features: the starting frequency is low (from 1Hz); the load is large (a single spring bears more than 3667Kg of load); the vibration signal is mixed with stochastic components. In this paper, models of an improved passive vibration isolation system and a semi-active fuzzy vibration control system of a geophysical prospecting car frame are established and simulated respectively. In the semi-active fuzzy control system the stiffness of an air spring is adjusted, and at the same time the impact by damping changes on the system performance is also taken into account. In order to evaluate the effects, the displacement and acceleration of car frame and the dynamic load of air spring are taken to comparative analysis. The results indicate that the proposed semi-active scheme can effectively lower the damage from vibroseis to the body of the car.

scholarly journals Planar Dynamics of a Motorcycle: Influence of Vibration Isolation System Nonlinearity

2020 ◽  
Vol 25 (4) ◽  
pp. 597-608
Author(s):  
Sudhir Kaul
Keyword(s):  
Vibration Isolation ◽  
Ride Comfort ◽  
Spatial Dynamics ◽  
Linearization Method ◽  
Statistical Linearization ◽  
Coupled Dynamics ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Nonlinear Design ◽  
System Nonlinearity

This paper investigates the influence of the nonlinearities of a vibration isolation system on the planar dynamics of a motorcycle. The use of a nonlinear isolation system is often necessitated by design and packaging constraints. Although the use of a vibration isolation system is uncommon in motorcycles, it is used in some cases to enhance ride comfort by mitigating vibrations transmitted to the rider due to shaking forces. In such cases, the handling of the motorcycle can be influenced due to the coupled dynamics of the rear unsprung mass and the swing arm. In this paper, a stochastic analysis has been performed by using the statistical linearization method to specifically examine nonlinearities associated with the vibration isolation system. An eight degree-of-freedom planar model has been developed, and each isolator is represented by a modified multi-axial Kelvin-Voigt model. It has been observed that the model developed in this study can capture the coupled dynamics between the rear suspension and the vibration isolation system. Results indicate that the nonlinear design of the vibration isolation system can be useful in enhancing ride comfort in the lower frequency range without an adverse impact on handling. Furthermore, it has been observed that the parameters associated with the nonlinear vibration isolation system can be tuned to enhance ride comfort while meeting the design requirements of spatial dynamics.

scholarly journals Influence of a Vibration Isolation System on Planar Dynamics of a Motorcycle

2020 ◽  
Vol 25 (1) ◽  
pp. 96-103
Author(s):  
Sudhir Kaul
Keyword(s):  
Simple Model ◽  
Design Process ◽  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Ride Comfort ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Natural Modes ◽  
The Impact ◽  
Unsprung Mass

This paper examines a model to investigate the impact of a vibration isolation system on the planar (in-plane) dynamics of a motorcycle. While it is not very common, a vibration isolation system is used in some motorcycles to mitigate vibrations resulting from the shaking forces of the engine. For such layouts, the powertrain is assembled to the frame through the vibration isolation system that typically consists of two to four isolators. It is critical to comprehend the influence of the isolation system on the overall dynamic characteristics of the motorcycle due to the coupled dynamics of the rear suspension, the isolation system, and the rear unsprung mass. The influence of a vibration isolation system on the in-plane dynamics is analysed by using a relatively simple model that has been developed in this study. This model has been used to evaluate the influence of the isolation system on natural modes, transmissibility, and ride comfort. Results indicate that the use of a vibration isolation system couples the rear unsprung hop to the pitch motion of the powertrain with a slight increase in the corresponding natural frequency. Results indicate that the use of a vibration isolation system directly affects handling of the motorcycle. Furthermore, results indicate that the pitch of the sprung mass and the hop of the rear unsprung mass are particularly influenced by the vibration isolation system. The model presented in this paper could be useful in the early stages of the design process to compare the rigidly mounted powertrain to different layouts of the vibration isolation system.

Vehicle Vibration Safety Evaluation in the Time Domain

2018 ◽  
pp. 1-15 ◽  
Author(s):  
L. F. Zheglov ◽  
A. B. Fominykh
Keyword(s):  
Dynamic System ◽  
Frequency Domain ◽  
Time Domain ◽  
Vibration Isolation ◽  
Natural Frequencies ◽  
Spectral Characteristics ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Calculation Results ◽  
The Time Domain

The article is a sequel to studies of the nonlinear vibration isolation systems of a vehicle. The first published papers considered an application of the known methods of statistical linearization when determining the vibration safety performance in the frequency domain. The frequency domain is the most adaptive in the context of analysis of the obtained calculation results and evaluation of the initial dynamic system features. Therefore, a problem to determine the adequacy range of such calculations in the frequency and time domain is relevant.The paper deals with the problem of creating a technique to determine and analyze the spectral characteristics of the vehicle vibration isolation system when modeling in the time domain. Considers as an object, a nonlinear dynamic system equivalent to the nonlinear vibration isolation system of a vehicle under its spatial vibrations. In formulating a system of equations-of-motion of the adopted system a module-based method was used. As an example, the power unit is given. Modeling of input random perturbations, provided that the solutions obtained are adequate, is based on the recurrent difference equations. The subsequent transformation of the calculation results into the frequency domain is based on the finite Fourier transforms.To determine the final parameters which characterise the effectiveness of the vibration isolation system, at the first stage of calculations the dynamic system was tested in a linear setting.The vector of natural frequencies of a conservative system defined in the frequency domain was compared with the spectrum of natural frequencies (the frequency response) calculated in the time domain. Besides, the article has carried out a conformity evaluation of the amplitude-frequency characteristics obtained in the frequency and time domain and their determining accuracy. The obtained positive results made it possible to compare and analyze the spectral characteristics of vibration signals and dynamic system in its nonlinear and linearized formulation. The coherence function, the amplitude-frequency characteristic, the spectral density of perturbation and output vibration signal, the vehicle suspension and tyre load characteristics are considered as the analyzed ones. The article compares the output characteristics of the dynamic system under consideration for the case in linear, linearized, and nonlinear formulation of the problem.

scholarly journals Performance of Variable Negative Stiffness MRE Vibration Isolation System

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Run-pu Li ◽  
Cheng-bin Du ◽  
Fei Guo ◽  
Guo-jun Yu ◽  
Xiao-guo Lin
Keyword(s):  
Magnetic Particles ◽  
Vibration Isolation ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Vibration Response ◽  
Negative Stiffness ◽  
Iron Core ◽  
Particle Volume ◽  
Isolation System ◽  
The Impact

Magnetorheological elastomer (MRE) vibration isolation devices can improve a system’s vibration response via adjustable stiffness and damping under different magnetic fields. Combined with negative stiffness design, these MRE devices can reduce a system’s stiffness and improve the vibration control effect significantly. This paper develops a variable negative stiffness MRE isolation device by combining an improved separable iron core with laminated MREs. The relationship between the negative stiffness and the performance of the device is obtained by mathematical transformation. Its vibration response under simple harmonic excitation at small amplitude and the impact of the volume fraction of soft magnetic particles on the isolation system are also analyzed. The results show that the negative stiffness produced by the magnetic force is a major factor affecting the capacity of the isolation system. Compared to devices of the same size, the isolation system equipped with low-particle volume fraction MREs demonstrates better performance.

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