Simulation of the Dynamic Behavior of Bedding-Foundation-Soil in the Time Domain

2003 ◽  
pp. 357-376
Author(s):  
Mohammad Firuziaan ◽  
Otto Estorff
Keyword(s):  
Dynamic Behavior ◽  
Time Domain ◽  
Foundation Soil ◽  
The Time Domain

scholarly journals Normalized Study of Three-Parameter System in the Time Domain and Frequency Domain

2017 ◽  
Vol 2017 ◽  
pp. 1-21
Author(s):  
Xiao-Lei Jiao ◽  
Yang Zhao ◽  
Wen-Lai Ma
Keyword(s):  
Frequency Domain ◽  
Dynamic Behavior ◽  
Time Domain ◽  
Phase Margin ◽  
Stiffness Ratio ◽  
Parameter System ◽  
Regulatory Factor ◽  
First Case ◽  
The Time Domain ◽  
Isolation Performance

Three-parameter isolation system can be used to isolate microvibration for control moment gyroscopes. Normalized analytical model for three-parameter system in the time domain and frequency domain is proposed by using analytical method. Dynamic behavior of three-parameter system in the time domain and frequency domain is studied. Response in the time domain under different types of excitations is analyzed. In this paper, a regulatory factor is defined in order to analyze dynamic behavior in the frequency domain. For harmonic excitation, a comparison study is made on isolation performance between the case when the system has optimal damping and the case when regulatory factor is 1. Besides, phase margin of three-parameter system is obtained. Results show that dynamic behavior in the time domain and frequency domain changes with regulatory factor. Phase margin has the largest value when the value of regulatory factor is 1. System under impulse excitation and step excitation has the shortest settling time for the response in the time domain when the value of regulatory factor is 1. When stiffness ratio is small, isolation performances of two cases are nearly the same; when system has a large stiffness ratio, isolation performance of the first case is better.

Finite Element Modelling of Rotating Tires in the Time Domain

2002 ◽  
Vol 30 (1) ◽  
pp. 19-33 ◽  
Author(s):  
O. A. Olatunbosun ◽  
A. M. Burke
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Time Domain ◽  
Equations Of Motion ◽  
Operating Conditions ◽  
Element Analysis ◽  
Successful Model ◽  
Linear Effects ◽  
Tire Rotation ◽  
The Time Domain

Abstract Finite element analysis presents an opportunity for a detailed study of the dynamic behavior of a rotating tire under real operating conditions providing a better understanding of the influence of tire construction and material detail on tire dynamic behavior in such areas as ride, handling and noise and vibration transmission. Modelling issues that need to be considered include non-linear effects due to tire inflation and hub loading, tire/road contact and time domain solution of the equations of motion. In this paper techniques and strategies for tire rotation modelling are presented and discussed as a guide to the creation of a successful model.

scholarly journals Time-Domain Dynamic Modeling and Analysis of Complex Heavy-Duty Gearbox Considering Floating Effect

2021 ◽  
Vol 11 (15) ◽  
pp. 6876
Author(s):  
Jiulin Wu ◽  
Yifan Zhou ◽  
Wei Jiang ◽  
Xuedong Chen
Keyword(s):  
Dynamic Behavior ◽  
Time Domain ◽  
Planetary Gear ◽  
Modeling Method ◽  
Torsional Stiffness ◽  
Heavy Duty ◽  
Wind Turbine Gearbox ◽  
Modeling And Analysis ◽  
Meshing Gears ◽  
The Time Domain

Expert insights into the time-domain dynamic behavior of heavy-duty gearboxes form the foundations of design evaluation and improvement. However, in the existing lateral–torsional coupling (LTC) modeling method for gearboxes that is normally used for frequency-domain dynamic behavior, the meshing forces are modeled as spring dampers with fixed acting points on the meshing gears to simulate only the transient LTC effect, and thus the steady state characteristic in the time domain cannot be obtained due to the unrealistic distortion of positions and orientations as the gear angles increase. In this paper, a novel and generally applicable LTC modeling method for heavy-duty gearboxes, mainly planetary gear sets with floating components, is proposed by using space-fixed spring dampers with floating acting points on the meshing gears to study the time-domain dynamic response and to support the dynamic design of heavy-duty gearboxes. Based on the proposed method, a LTC model of a 2 megawatt (MW) wind turbine gearbox with floating components considering the time-varying meshing stiffness, bearing stiffness, torsional stiffness, and floating effect was established. The simulated results of representative components were in accordance with experimental results on a test rig, and dynamic behavior was calculated.

Dynamic response of soft soils in high-speed rail foundation: in situ measurements and time domain finite element method model

2019 ◽  
Vol 56 (12) ◽  
pp. 1832-1848 ◽  
Author(s):  
Yiqun Tang ◽  
Qi Yang ◽  
Xingwei Ren ◽  
Siqi Xiao
Keyword(s):  
Dynamic Response ◽  
Time Domain ◽  
High Speed ◽  
In Situ Measurements ◽  
Vertical Acceleration ◽  
High Speed Rail ◽  
Foundation Soil ◽  
Train Speed ◽  
The Time Domain

The dynamic response of soil to vibrations induced by moving trains has been widely studied using in situ measurements. However, few in situ tests have been conducted to measure the resulting vibration of foundation soils, especially for the foundation of high-speed rail (HSR) in a soft area. In this study, a number of field experiments were conducted on Shanghai–Hangzhou HSR in a suburb of Shanghai, China. The testing instruments were installed in foundation soils just beneath the HSR track to measure the vibration induced by trains moving at different speeds. Test results show the frequencies of foundation soil vibration are characterized by the train speed and geometrical features of the trains and slab track. In the frequency domain, the dominant frequency bands for vertical acceleration, velocity, and displacement of foundation soil decrease successively. In the time domain, the magnitudes of vibration levels at different locations in a soil foundation decrease gradually with increasing distance from the track. Furthermore, higher train speed can result in higher vibration level. Based on the field conditions, a three-dimensional dynamic finite–infinite element model is developed in the time domain. It shows the model is capable of capturing the primary characteristics of train-induced vibration in the field.

Experimental Investigation on the Lumped Model of Nonlinear Rocker–Rocker Mechanism With Flexible Coupler

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Ren-Jung Chang ◽  
Ying-Chuan Wang
Keyword(s):  
Dynamic Behavior ◽  
Time Domain ◽  
Linear Time ◽  
Harmonic Balance Method ◽  
Model Averaging ◽  
Lumped Model ◽  
Linear Time Invariant ◽  
Domain Identification ◽  
Flexible Mechanism ◽  
The Time Domain

Abstract The nonlinear and flexible effects on the continuum dynamics of rocker–rocker flexible mechanism are investigated. An experimental rocker–rocker mechanism with flexible coupler was first established. The flexible mechanism which incorporats the buckling motion of flexible coupler is acted as a double-well oscillator. The mechanism was actuated by electromagnet and measured by charge-coupled device (CCD) visual system. Rich dynamic behavior such as complex period, amplitude modulation, and chaos in the intrawell and interwell oscillations were observed. For investigating nonlinear dynamics, the dynamic behavior was analyzed through identification of linear and nonlinear lumped models. Both time-domain and frequency-domain approaches were carried out in identifying linear time-invariant model. Averaging multiple models were employed for the time-domain identification of linear model. The identification of nonlinear model was undertaken by the extension of the two-stage linear identification scheme. The response identification in input space was analyzed by utilizing semi-analytical harmonic balance method. The important boundary of chaotic response in operation was investigated by the proposed energy-well criterion, Melnikov's criterion, Moon's criterion, as well as Szemplińska-Stupnicka and Rudowski's criterion.

Dynamic Behavior of a Vertical Production Riser by Quasi 3D Calculations

2003 ◽  
Author(s):  
C. K. Morooka ◽  
H. Y. Kubota ◽  
K. Nishimoto ◽  
J. A. Ferrari ◽  
E. J. B. Ribeiro
Keyword(s):  
Numerical Simulations ◽  
Dynamic Behavior ◽  
Time Domain ◽  
3D Model ◽  
Wave Loads ◽  
Environmental Loads ◽  
The Time Domain ◽  
Surface Vessel

A study on dynamics of a vertical production riser under environmental loads is carried out. Current and wave loads along the riser, and surface vessel motions due to the environment at the riser top are taken into account. Based on descriptions of fundamentals of the Quasi 3D model previously proposed by Ferrari&Bearman (1999), numerical simulations for riser displacements have been performed. In line and transverse hydrodynamic current and wave loads on the riser are estimated and riser displacements thought Quasi 3D fashion are estimated in the time domain. Comparisons with literature results and experimental ones are carried out.

Technique for Efficient Time-Domain Analysis of Complete Buoy-Cable Systems

1979 ◽  
Vol 101 (4) ◽  
pp. 416-420 ◽  
Author(s):  
H. T. Wang
Keyword(s):  
Elastic Modulus ◽  
Computer Program ◽  
Dynamic Behavior ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Transient Phase ◽  
Two Dimensional ◽  
Cable Systems ◽  
The Time Domain

A brief description is given of a computer program for the time domain analysis of the two-dimensional dynamic behavior of general ocean buoy-cable-body systems. Several sample problems are given to illustrate the versatility of the program. The concept of using the results for a cable with reduced elastic modulus, adjusted so that the cable does not stretch, to predict the dynamic behavior of a nearly inextensible cable with much higher elastic modulus is discussed in detail. Except for the transient phase, it is shown that this technique generally predicts tensions and motions with errors of only a few percent for nearly inextensible cables which would otherwise require substantially longer computer times.

Apodisation in the time domain

1992 ◽  
Vol 2 (4) ◽  
pp. 615-620
Author(s):  
G. W. Series
Keyword(s):  
Time Domain ◽  
The Time Domain

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

Sign in / Sign up

Export Citation Format

Share Document