scholarly journals Online Identification of a Mechanical System in the Frequency Domain with Short-Time DFT

2015 ◽  
Vol 36 (3) ◽  
pp. 157-165 ◽  
Author(s):  
Niko Nevaranta ◽  
Jukka Parkkinen ◽  
Tuomo Lindh ◽  
Markku Niemelä ◽  
Olli Pyrhönen ◽  
...  
Keyword(s):  
Mechanical System ◽  
Frequency Domain ◽  
Online Identification ◽  
Short Time

Online Identification of a Mechanical System in Frequency Domain Using Sliding DFT

2016 ◽  
Vol 63 (9) ◽  
pp. 5712-5723 ◽  
Author(s):  
Niko Nevaranta ◽  
Stijn Derammelaere ◽  
Jukka Parkkinen ◽  
Bram Vervisch ◽  
Tuomo Lindh ◽  
...  
Keyword(s):  
Mechanical System ◽  
Frequency Domain ◽  
Online Identification

scholarly journals Monitoring the dynamic behaviors of the Bosporus Bridge by GPS during Eurasia Marathon

2007 ◽  
Vol 14 (4) ◽  
pp. 513-523 ◽  
Author(s):  
H. Erdoğan ◽  
B. Akpınar ◽  
E. Gülal ◽  
E. Ata
Keyword(s):  
Frequency Domain ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Engineering Structures ◽  
Low Frequencies ◽  
Temperature Changes ◽  
Bridge Responses ◽  
Special Complex ◽  
Short Time

Abstract. Engineering structures, like bridges, dams and towers are designed by considering temperature changes, earthquakes, wind, traffic and pedestrian loads. However, generally, it can not be estimated that these structures may be affected by special, complex and different loads. So it could not be known whether these loads are dangerous for the structure and what the response of the structures would be to these loads. Such a situation occurred on the Bosporus Bridge, which is one of the suspension bridges connecting the Asia and Europe continents, during the Eurasia Marathon on 2 October 2005, in which 75 000 pedestrians participated. Responses of the bridge to loads such as rhythmic running, pedestrian walking, vehicle passing during the marathon were observed by a real-time kinematic (RTK) Global Positioning System (GPS), with a 2.2-centimeter vertical accuracy. Observed responses were discussed in both time domain and frequency domain by using a time series analysis. High (0.1–1 Hz) and low frequencies (0.00036–0.01172 Hz) of observed bridge responses under 12 different loads which occur in different quantities, different types and different time intervals were calculated in the frequency domain. It was seen that the calculated high frequencies are similar, except for the frequencies of rhythmic running, which causes a continuously increasing vibration. Any negative response was not determined, because this rhythmic effect continued only for a short time. Also when the traffic load was effective, explicit changes in the bridge movements were determined. Finally, it was seen that bridge frequencies which were calculated from the observations and the finite element model were harmonious. But the 9th natural frequency value of the bridge under all loads, except rhythmic running could not be determined with observations.

scholarly journals Online Identification of a Two-Mass System in Frequency Domain using a Kalman Filter

2016 ◽  
Vol 37 (2) ◽  
pp. 133-147 ◽  
Author(s):  
Niko Nevaranta ◽  
Stijn Derammelaere ◽  
Jukka Parkkinen ◽  
Bram Vervisch ◽  
Tuomo Lindh ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Frequency Domain ◽  
Mass System ◽  
Online Identification

scholarly journals Payload Mass Identification of a Single-Link Flexible Arm Moving under Gravity: An Algebraic Identification Approach

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Juan Carlos Cambera ◽  
Andres San-Millan ◽  
Vicente Feliu-Batlle
Keyword(s):  
Frequency Domain ◽  
Design Methodology ◽  
Vertical Plane ◽  
Sensor Noise ◽  
Online Identification ◽  
Flexible Arm ◽  
Single Link ◽  
Identification Approach ◽  
Payload Mass ◽  
Mass Identification

We deal with the online identification of the payload mass carried by a single-link flexible arm that moves on a vertical plane and therefore is affected by the gravity force. Specifically, we follow a frequency domain design methodology to develop an algebraic identifier. This identifier is capable of achieving robust and efficient mass estimates even in the presence of sensor noise. In order to highlight its performance, the proposed estimator is experimentally tested and compared with other classical methods in several situations that resemble the most typical operation of a manipulator.

Frequency domain analysis of modes in a photonic crystal micro-opto-electro-mechanical system with periodically arranged circular holes

2012 ◽  
Vol 44 (3-5) ◽  
pp. 273-277
Author(s):  
Ugur Akcakoca ◽  
Bernd Witzigmann ◽  
Ricardo Zamora ◽  
Thomas Kusserow ◽  
Hartmut Hillmer
Keyword(s):  
Photonic Crystal ◽  
Mechanical System ◽  
Frequency Domain ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Circular Holes

scholarly journals Application of the Acoustic Emission Method for Diagnosis of On-Load Tap Changer

2017 ◽  
Vol 42 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Henryk Majchrzak ◽  
Andrzej Cichoń ◽  
Sebastian Borucki
Keyword(s):  
Acoustic Emission ◽  
Frequency Domain ◽  
Time Domain ◽  
Operating Conditions ◽  
Time Frequency ◽  
Measurement Results ◽  
Tap Changer ◽  
The Time Domain ◽  
Load Tap Changer ◽  
Short Time

Abstract This paper provides an example of the application of the acoustic emission (AE) method for the diagnosis of technical conditions of a three-phase on-load tap-changer (OLTC) GIII type. The measurements were performed for an amount of 10 items of OLTCs, installed in power transformers with a capacity of 250 MVA. The study was conducted in two different OLTC operating conditions during the tapping process: under load and free running conditions. The analysis of the measurement results was made in both time domain and time-frequency domain. The description of the AE signals generated by the OLTC in the time domain was performed using the analysis of waveforms and determined characteristic times. Within the time-frequency domain the measured signals were described by short-time Fourier transform spectrograms.

Research and analysis of the wheeled vehicle load spectrum editing method based on short-time Fourier transform

2019 ◽  
Vol 233 (14) ◽  
pp. 3671-3683
Author(s):  
Zongkai Liu ◽  
Chuan Peng ◽  
Xiaoqiang Yang
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Fatigue Damage ◽  
Time Domain ◽  
Short Time Fourier Transform ◽  
Load Spectrum ◽  
Statistical Parameters ◽  
Original Spectrum ◽  
The Time Domain ◽  
Short Time

The measured uniaxial-head load spectrum in the road simulation test has a large number of useless small loads. When applying the measured load spectrum directly, it will take a lot of time. This paper designs a comprehensive road spectrum measurement system to collect data and proposes a method for editing the uniaxial-head acceleration load spectrum using short-time Fourier transform to speed up the reliability test process and reduce time costs. In this method, the time domain and frequency domain information of the signal is obtained by short-time Fourier transform. The concept of accumulated power spectral density is proposed to identify the reduced load data, and the relative fatigue damage is used as the pass criterion. The length of the edited spectrum is only 66% of the original spectrum through the above-mentioned editing method and retains the relative damage amount of 91%. Finally, through the analysis of time domain, frequency domain, and fatigue statistical parameters, it demonstrates that the short-time Fourier transform–based acceleration load spectrum edition method could achieve a similar fatigue damage to the original spectrum in a shorter time.

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