A computer program for time‐domain modal vibration identification

1984 ◽  
Vol 75 (4) ◽  
pp. 1302-1302
Keyword(s):  
Computer Program ◽  
Time Domain ◽  
Modal Vibration

Coupling of Two Tools for the Simulation of Floating Wind Turbines

2013 ◽  
Author(s):  
Sébastien Gueydon ◽  
Koert Lindenburg ◽  
Feike Savenije
Keyword(s):  
Computer Program ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Domain Model ◽  
Offshore Wind ◽  
Floating Body ◽  
Research Centre ◽  
Floating Wind Turbine ◽  
Floating Offshore Wind Turbines

For the design of a floating wind turbine it is necessary to take the loading due to the wind, wave and current in equal consideration. The PHATAS computer program from ECN (Energy research Centre of the Netherlands) is a time-domain aero-elastic simulation program, that accounts for the complete mutual interaction of unsteady rotor aerodynamics, structural dynamics of the rotor blades and tower, and interaction with the turbine controller under influence of turbulent wind and wave loading for fixed wind turbines. The aNySIM computer program from MARIN is a multi rigid body time domain model that accounts for wave loadings, current loadings, wind loadings, floating body dynamics, mooring dynamics. The coupled computer program aNySIM / PHATAS accounts for all loadings acting on a floating wind turbine and its response whereas PHATAS can only be used for fixed wind turbines onshore and offshore. This paper reports on the dynamic coupling between PHATAS and aNySIM. As a typical case study, the controller for floating offshore wind turbines is evaluated. This new tool has been used to repeat phase IV of the Offshore Code Comparison Collaboration (OC3) within IEA Wind Task 23, regarding floating wind turbine modelling. The results of these simulations are presented in this paper.

A COMPUTER PROGRAM TO OBTAIN THE WEIGHTS OF A TIME‐DOMAIN WAVE‐SHAPING FILTER WHICH IS OPTIMUM IN AN ERROR‐DISTRIBUTION SENSE

Geophysics ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 197-215
Author(s):  
R. F. Mereu
Keyword(s):  
Computer Program ◽  
Time Domain ◽  
Input Signal ◽  
Output Signal ◽  
Error Distribution ◽  
Distribution Sense ◽  
Shaping Filter

The program presented in this paper (Appendix A) computes the weights of a time‐domain wave‐shaping filter F which will transform a given input signal into a desired output signal in an optimum “error‐distribution” sense (see Mereu, 1976).

Flexible Modelling of the Activated Sludge System – Theoretical and Practical Aspects

1985 ◽  
Vol 17 (2-3) ◽  
pp. 247-258 ◽  
Author(s):  
M. S. Sheffer ◽  
M. Hiraoka ◽  
K. Tsumura
Keyword(s):  
Model Selection ◽  
Computer Program ◽  
Time Domain ◽  
Mechanistic Models ◽  
Parameter Fitting ◽  
Modelling Method ◽  
Using Data ◽  
The Time Domain ◽  
Fitting In ◽  
Selection Of

For the purpose of optimal modelling, a “Flexible Modelling” method was developed. A flexible set of models consisting of hierarchical mechanistic models derived from a highly detailed structured model by mechanistic simplification was obtained. The performance of a computer program with an algorithm for parameter fitting in the time domain was evaluated by use of simulation. The program was able to estimate the models' parameters, even when using data with different degrees of inaccuracy. A computer program for model selection was developed, whereby the model was selected according to the information required. It was found that for prediction of the dynamic behavior of the MLVSS, the simplest model can supply all the necessary information. For prediction of effluent substrate concentration, the differences between the models' predictions depend on the characteristics of the disturbances and on the values of the models' parameters. The selection of the proper model and updating its parameters can be done by a computer which uses the presented program for model selection and parameter fitting.

Application of Vibration Analysis in Ball Bearing Fault Detection

2005 ◽  
Author(s):  
F. Bakhtiary-Nejad ◽  
A. H. Nayeb ◽  
S. E. Yeganeh
Keyword(s):  
Fault Detection ◽  
Computer Program ◽  
Time Domain ◽  
Vibration Analysis ◽  
Ball Bearing ◽  
Detection Method ◽  
Ball Bearings ◽  
Test Results ◽  
Localized Defects ◽  
Set Up

In this paper, existence of localized defects in a ball bearing has been diagnosed using vibration analysis. First, different kinds of faults which occur in ball bearings have been investigated. Then an analytical model has been proposed for determining the damaged ball bearing vibrations due to a localized defect. Also various methods of fault detection have been evaluated. Next, in order to examine the ball bearings, a testing set-up has been designed and constructed. Then by preparing a computer program, which calculates defect frequencies, some ball bearings have been tested. The test results were originally derived in time-domain. Then by using vibration analysis of healthy and damaged ball bearings in frequency-domain, a fault detection method for ball bearings has been proposed.

FAST AND ACCURATE TIME-DOMAIN ANALYSIS OF PIECEWISE-LINEAR DYNAMICS CIRCUITS: THE COMPUTER PROGRAM PILA

1994 ◽  
Vol 04 (01) ◽  
pp. 71-92 ◽  
Author(s):  
MARIO BIEY ◽  
MARTIN HASLER ◽  
ROBERTO LOJACONO ◽  
AMEDEO PREMOLI
Keyword(s):  
Computer Program ◽  
Time Domain ◽  
Piecewise Linear ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
State Matrix ◽  
Linear Region ◽  
All Solutions ◽  
The Time Domain

The computer program PILA (piecewise-linear analysis) is described. It is specially designed for exploring complicated dynamics of moderately sized piecewise-linear circuits. The DC-analysis is performed either by an adapted version of Katzenelson’s algorithm or by an algorithm designed for solving the linear complementarity problem. If the user chooses the latter algorithm, he will get all solutions of the DC-problem, whereas with Katzenelson’s algorithm usually just one solution is found. The time-domain analysis proceeds by the calculation of eigenvalues of the state matrix in order to obtain a time-symbolic solution in each linear region. This method is particularly fast and accurate, as long as the order of the circuit is not too high. The main errors occur in the determination of the transition between two adjacent linear regions. Particular care has been taken to get maximum transition accuracy. Some examples illustrate the various features of PILA.

Dynamic Analysis for Transportation of Barge-Jacket Assembly in Time-Frequency Domain

1988 ◽  
Vol 110 (2) ◽  
pp. 109-116
Author(s):  
F. Sun ◽  
C. Gao
Keyword(s):  
Computer Program ◽  
Frequency Domain ◽  
Time Domain ◽  
Fourier Transformation ◽  
Time History ◽  
Statistical Characteristics ◽  
Frequency Domain Method ◽  
Time Frequency ◽  
Random Seas ◽  
History Of

A combined time-frequency domain method is proposed to analyze the stresses of barge-jacket assembly during transportation. Starting with the motion of analysis in frequency domain, the time history of waves and motions in random seas are simulated, then the stresses are determined in time domain. The stress autocorrelation functions are calculated and the stress spectra and statistical characteristics are obtained through Fourier transformation. A computer program has been developed. The effects of barge flexibility and the forces caused by the immersion of jacket have been discussed.

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