Condition of modal analysis in time domain of lossy coupled lines

1988 ◽  
Vol 24 (20) ◽  
pp. 1289 ◽  
Author(s):  
P. Crozat ◽  
A. Zounon ◽  
R. Adde
Keyword(s):  
Modal Analysis ◽  
Time Domain ◽  
Coupled Lines

Coupled Analysis of an FPSO and Dry Tree Unit Connected by a Gravity Actuated Pipe (GAP)

2008 ◽  
Author(s):  
Mamoun Naciri ◽  
Helene Schaegis ◽  
Guillaume Ardoise
Keyword(s):  
South China Sea ◽  
Modal Analysis ◽  
South China ◽  
Water Depth ◽  
Time Domain ◽  
Coupled Analysis ◽  
Transfer Lines ◽  
Field Development ◽  
Fluid Transfer ◽  
First Time

MURPHY Sabah Oil Co. Ltd. has developed the Kikeh Field located offshore Malaysia in the South China Sea in a water depth of 1325m. This field development is based on a Floating Production Storage and Offloading unit (FPSO) and a Spar Dry Tree Unit (DTU). Fluids are transported in fluid transfer lines (FTL) using SBM’s newly developed and patented Gravity Actuated Pipe (GAP) system. To our knowledge this is the first time two large moored floaters are connected together by a slender body closing a gap of 1600m. It was not clear at the beginning of the project to what extent the first and second order motions of the two floaters were coupled, if at all, owing to the presence of the GAP system. To investigate the extent of coupling, both frequency domain (modal analysis) and time domain analyses of the FPSO, GAP system and Dry Tree Unit were performed. The salient features and results are presented.

Blind Separation of Excavator Noise Signals in Frequency Domain

2011 ◽  
Vol 105-107 ◽  
pp. 723-728
Author(s):  
Li Da Liao ◽  
Qing Hua He ◽  
Zhong Lin Hu
Keyword(s):  
Independent Component Analysis ◽  
Modal Analysis ◽  
Frequency Domain ◽  
Time Domain ◽  
Component Analysis ◽  
Independent Component ◽  
Blind Separation ◽  
Noise Sources ◽  
Amplitude Spectra ◽  
Complex Valued

In order to identify noise sources of an excavator in non-library environment, a complex-valued algorithm in frequency domain was applied. Firstly, an acoustic camera was used to acquire excavator’s noise signals, which were convolutive mixtures in time domain interfered by echo. Secondly, signals in time domain transformed into frequency domain by FT, turned to be complex-valued mixtures. Then, independent components of noise signals were obtained through separation of complex-valued mixtures using complex-valued algorithm based on independent component analysis. Finally, according to noise of diesel with muffler was mainly consist of surface noise, the relationship between principal frequencies and structrual parts was founded by comparing frequency-amplitude spectra and modal analysis in Ansys. Research shows that complex-valued algorithm based on fast fixed-point independent component analysis can effectively separate noise signals from an excavator in time domain, and noise sources can be well ascertained by comparing the modal analysis with blind separation components.

Time domain CAD and measurements of lossy coupled lines

1990 ◽  
Vol 26 (7) ◽  
pp. 473
Author(s):  
A. Zounon ◽  
P. Crozat ◽  
R. Adde
Keyword(s):  
Time Domain ◽  
Coupled Lines
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