Response of viscoelastic damping system modeled by fractional viscoelastic oscillator

2016 ◽  
Vol 231 (17) ◽  
pp. 3169-3180 ◽  
Author(s):  
ZL Li ◽  
DG Sun ◽  
BH Han ◽  
B Sun ◽  
X Zhang ◽  
...  
Keyword(s):  
Engineering Application ◽  
Geometric Factor ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Fractional Model ◽  
Proposed Model ◽  
Considerable Impact ◽  
Control Capability ◽  
Viscoelastic Oscillator ◽  
Damping Systems

The fractional model considering geometric factor of viscoelastic damping systems is proposed by adopting fractional viscoelastic oscillator. To obtain dynamic responses of the fractional model, a numerical method is derived based on matrix function theory and Grumwald–Letnikov discrete form of fractional derivative. As a special engineering application example, the vibration response of the viscoelastic suspension installed in heavy crawler-type vehicles is studied through the proposed model. Furthermore, the parameter influence on the vibration control capability of the viscoelastic suspension is researched. The results indicate that the fractional viscoelastic oscillator is a favorable choice to characterize the dynamic behavior of viscoelastic damping structures. Additionally, the parameters in fractional viscoelastic oscillator namely geometric factor and fractional order exert considerable impact on the dynamic response of viscoelastic damping structures.

scholarly journals Lane Departure Warning Estimation Using Yaw Acceleration

2020 ◽  
Vol 11 (1) ◽  
pp. 102-111
Author(s):  
Em Poh Ping ◽  
J. Hossen ◽  
Wong Eng Kiong
Keyword(s):  
Vehicle Dynamics ◽  
Dynamic Responses ◽  
Dynamics Simulation ◽  
Steering Wheel ◽  
Mathematical Representation ◽  
Vehicle Speed ◽  
Lane Departure Warning ◽  
Model Based ◽  
Lane Departure ◽  
Proposed Model

AbstractLane departure collisions have contributed to the traffic accidents that cause millions of injuries and tens of thousands of casualties per year worldwide. Due to vision-based lane departure warning limitation from environmental conditions that affecting system performance, a model-based vehicle dynamics framework is proposed for estimating the lane departure event by using vehicle dynamics responses. The model-based vehicle dynamics framework mainly consists of a mathematical representation of 9-degree of freedom system, which permitted to pitch, roll, and yaw as well as to move in lateral and longitudinal directions with each tire allowed to rotate on its axle axis. The proposed model-based vehicle dynamics framework is created with a ride model, Calspan tire model, handling model, slip angle, and longitudinal slip subsystems. The vehicle speed and steering wheel angle datasets are used as the input in vehicle dynamics simulation for predicting lane departure event. Among the simulated vehicle dynamic responses, the yaw acceleration response is observed to provide earlier insight in predicting the future lane departure event compared to other vehicle dynamics responses. The proposed model-based vehicle dynamics framework had shown the effectiveness in estimating lane departure using steering wheel angle and vehicle speed inputs.

scholarly journals Nonlinear Dynamic Characteristic Analysis of a Landing String in Deepwater Riserless Drilling

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Jun Liu ◽  
Hongliang Zhao ◽  
Simon X. Yang ◽  
Qingyou Liu ◽  
Guorong Wang
Keyword(s):  
Boundary Condition ◽  
Dynamic Model ◽  
Marine Environment ◽  
Lower Boundary ◽  
Dynamic Responses ◽  
Characteristic Analysis ◽  
Lower Boundary Condition ◽  
Response Characteristics ◽  
Proposed Model ◽  
Nonlinear Dynamic Characteristic

The landing string is an important component of deepwater riserless drilling systems. Determination of the dynamic characteristics of the landing string plays an essential role in its design for ensuring its safe operation. In this paper, a dynamic model is developed to investigate the dynamic response characteristics of a landing string, where a landing string in a marine environment is modeled as a flexible slender tube undergoing coupled transverse and axial motions. The heaving motion of the drilling platform is taken as the upper boundary condition and the motion of the drilling bit caused by the interaction between the rock and the bit as the lower boundary condition. A semiempirical Morison equation is used to simulate the effect of the load imposed by the marine environment. The dynamic model, which is nonlinearly coupled and multibody, is discretized by a finite element method and solved by the Newmark technique. Using the proposed model, the dynamic responses of the displacement, axial force, and moment in the landing string are investigated in detail to find out the influences of driving depth of surface catheter, platform motion, bit movement, and marine environment on the dynamical characteristics of the landing string.

A Possibility Estimation Model and its Application

2013 ◽  
Vol 475-476 ◽  
pp. 423-427
Author(s):  
Lin Na Ji ◽  
Feng Bao Yang ◽  
Xiao Xia Wang
Keyword(s):  
Measurement Data ◽  
Engineering Application ◽  
Transformation Method ◽  
Estimation Model ◽  
Property Estimation ◽  
New Methods ◽  
Proposed Model ◽  
Practical Engineering ◽  
New Ideas ◽  
Possibility Distributions

Aiming at some uncertainty problems such as quality inspection of adhesive structure and risk assessment in the practical engineering application, a possibility estimation model is established. Firstly, according to the fuzziness, randomness and uncertainty of the measurement data, a transformation method of possibility distribution with non-single peak values and nonlinearity is proposed from probability density function. Secondly, for possibility distributions of measurement data of each sensor, a kind of possibility fusion rules is put forward, then the fusion distribution is estimated by the possibility mean. Finally the model is applied to the mechanical property estimation of adhesive structure, and the result forecasts the quality. The proposed model with strong applicability, not only provides convenience for the operations among possibility distributions, but also offers new ideas and new methods to deal with uncertain problems.

Dynamic Analysis of a Cylindrical Roller Bearing With Time-Varying Localized Defects on Raceways

2015 ◽  
Author(s):  
Fengtao Wang ◽  
Li Chen ◽  
Heng Liu ◽  
Minqing Jing ◽  
Wei Chen ◽  
...  
Keyword(s):  
Roller Bearing ◽  
Step Function ◽  
Dynamic Responses ◽  
Experimental Comparison ◽  
Time Varying ◽  
Proposed Model ◽  
Time Domains ◽  
Localized Defects ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

An existing defect on the bearing raceway may evolve with the interactions between the bearing elements, and the evolutions of the defect may be divided into different stages. In this study, a dynamic model for a cylindrical roller bearing with localized defects on raceways is developed to investigate vibration character of the bearing in these stages. The coupling of centrifugal forces, gravity forces and the slipping of the roller are considered. The half sine function and step function are used to construct time-varying models of defects in different stages, which is reflected on the local deflection. The system dynamic equations are solved by the fourth-order Runge-Kutta integration method with variable steps. Time domains and frequency domains are used to analyze dynamic responses of the bearing in every defect stage, which can be used as a reference of fault diagnosis. An experimental comparison in the previous study is carried out to validate the proposed model.

Development and Challenge of the Vehicle and Highway Bridges Dynamic Interaction

2013 ◽  
Vol 574 ◽  
pp. 135-150
Author(s):  
Jia Feng Liu ◽  
Yan Li
Keyword(s):  
Analytical Model ◽  
High Speed ◽  
Engineering Application ◽  
Highway Bridges ◽  
Dynamic Interaction ◽  
Dynamic Responses ◽  
Coupling Vibration ◽  
Safety Control ◽  
Main Research ◽  
Long Span

With the development of long-span flexible bridges and the increase of highway transportation, both the dynamic responses of highway bridges under high-speed and heavy vehicles and the safety control of vehicles have deserved general concerns. First, this paper briefly discussed some researches on coupling vibration of vehicle and highway-bridges, then roundly summarized main research achievements accounting on the vehicle analytical model, bridge analytical model, surface roughness of road, numerical method of vehicle-bridge coupling vibration and some other aspects. Meanwhile, some research trends and challenge on vehicle and bridge dynamic interaction in engineering application were pointed out.

scholarly journals Nonlinear Dynamics of Imperfect FGM Conical Panel

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Yan Niu ◽  
Yuxin Hao ◽  
Minghui Yao ◽  
Wei Zhang ◽  
Shaowu Yang
Keyword(s):  
Nonlinear Dynamics ◽  
Equations Of Motion ◽  
Engineering Application ◽  
Shear Deformation Theory ◽  
Harmonic Excitation ◽  
Functionally Graded ◽  
Dynamic Responses ◽  
Phase Portraits ◽  
Power Law Distribution ◽  
Geometric Imperfection

Structures composed of functionally graded materials (FGM) can satisfy many rigorous requisitions in engineering application. In this paper, the nonlinear dynamics of a simply supported FGM conical panel with different forms of initial imperfections are investigated. The conical panel is subjected to the simple harmonic excitation along the radial direction and the parametric excitation in the meridian direction. The small initial geometric imperfection of the conical panel is expressed by the form of the Cosine functions. According to a power-law distribution, the effective material properties are assumed to be graded along the thickness direction. Based on the first-order shear deformation theory and von Karman type nonlinear geometric relationship, the nonlinear equations of motion are established by using the Hamilton principle. The nonlinear partial differential governing equations are truncated by Galerkin method to obtain the ordinary differential equations along the radial displacement. The effects of imperfection types, half-wave numbers of the imperfection, amplitudes of the imperfection, and damping on the dynamic behaviors are studied by numerical simulation. Maximum Lyapunov exponents, bifurcation diagrams, time histories, phase portraits, and Poincare maps are obtained to show the dynamic responses of the system.

Thermomechanical Fractional Derivative Model of Viscoelastic Isolators

2014 ◽  
Vol 952 ◽  
pp. 219-222
Author(s):  
Zhen Li Zhang ◽  
Chao Shang ◽  
Wei Hua Shi
Keyword(s):  
Fractional Derivative ◽  
Engineering Application ◽  
Coupling Model ◽  
Measured Data ◽  
Thermomechanical Coupling ◽  
Damping Characteristics ◽  
Fractional Derivative Model ◽  
Proposed Model ◽  
Vibration Process ◽  
Difference Form

In vibration process, viscoelastic isolators’ temperature will rise due to energy dissipation, especially when the isolators have high damping characteristics. First, for the arbitrary loadings, the thermomechanical coupling model and the corresponding difference form are established based on the five-parameter fractional derivative model. Then, for the steady-state harmonic inputs, which is very common in engineering application, the derived model is significantly simplified by Fourier transformation. Finally, the proposed model is verified by experiments and shows a reasonable agreement with measured data.

Dynamic Responses of Plates With Viscoelastic Free Layer Damping Treatment

1996 ◽  
Vol 118 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Sung Yi ◽  
M. Fouad Ahmad ◽  
H. H. Hilton
Keyword(s):  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Free Layer ◽  
Modulus Ratio ◽  
Transient Responses ◽  
Damping Materials

Dynamic transient responses of plates with viscoelastic free damping layers are studied in order to evaluate free layer damping treatment performances. The effects of forcing frequencies and temperatures on free-layer viscoelastic damping treatment of plates are investigated analytically. Young’s modulus ratio of structures to viscoelastic damping materials and the damping layer thickness effects on the damping ability are also explored.

Dynamic Analysis of a Geared Rotor-Bearing System with Time-Varying Gear Mesh Stiffness and Pressure Angle

2013 ◽  
Vol 284-287 ◽  
pp. 461-467
Author(s):  
Ying Chung Chen ◽  
Chung Hao Kang ◽  
Siu Tong Choi
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Responses ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Pressure Angle ◽  
Proposed Model ◽  
Rotor Bearing ◽  
Gear Mesh Stiffness ◽  
Bearing System

The dynamic analysis of a geared rotor-bearing system with time-varying gear mesh stiffness and pressure angle is presented in this paper. Although there are analyses for both of the gear and rotor-bearing system dynamics, the coupling effect of the time-varying mesh and geared rotor-bearing system is deficient. Therefore, the pressure angle and contact ratio of the geared rotor-bearing system are treated as time-varying variables in the proposed model while they were considered as constant in previous models. The gear mesh stiffness is varied with different contact ratios of the gear pair in the meshing process. The nonlinear equations of motion for the geared rotor-bearing system are obtained by applying Lagrange’s equation and the dynamic responses are computed by using the Runge-Kutta numerical method. Numerical results of this study indicated that the proposed model provides realistic dynamic response of a geared rotor-bearing system.

scholarly journals Modelling Yawed Wind Turbine Wakes: Extension of a Gaussian-Based Wake Model

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4494
Author(s):  
De-Zhi Wei ◽  
Ni-Na Wang ◽  
De-Cheng Wan
Keyword(s):  
Transverse Velocity ◽  
Engineering Application ◽  
Streamwise Velocity ◽  
Steering Control ◽  
Eddy Simulation ◽  
Proposed Model ◽  
Large Eddy ◽  
Wake Model ◽  
Short Time ◽  
Far Wake

Yaw-based wake steering control is a potential way to improve wind plant overall performance. For its engineering application, it is crucial to accurately predict the turbine wakes under various yawed conditions within a short time. In this work, a two-dimensional analytical model is proposed for far wake modeling under yawed conditions by taking the self-similarity assumption for the streamwise velocity deficit and skewness angle at hub height. The proposed model can be applied to predict the wake center trajectory, streamwise velocity, and transverse velocity in the far-wake region downstream of a yawed turbine. For validation purposes, predictions by the newly proposed model are compared to wind tunnel measurements and large-eddy simulation data. The results show that the proposed model has significantly high accuracy and outperforms other common wake models. More importantly, the equations of the new proposed model are simple, the wake growth rate is the only parameter to be specified, which makes the model easy to be used in practice.

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