... spatial distribution completely coincides with the natural mode shape of the pipe system. Harmonic analysis is performed to obtain the maximum stress range at each natural frequency of the piping system. From the transfer function and pressure fluctuation spectrum, a stress range spectrum can...

... each data set, the deployed riser length varies over time. Measured riser response data sets from load cells and accelerometers, have been analyzed to determine the first axial riser natural frequency and associated damping ratio using robust identification methods. Damping ratio values are presented...

... displacement tension variation modeling & simulation wellhead fatigue spectra natural frequency riser vessel motion frequency Gryt0yr , G. , Coral , F. , Lindstad , H. B. , and Russo , M. , "Wellhead Fatigue Damage Based on Indirect Measurements," Proc. 34th...

... damage rates compared well with pre-deployment predictions, though measured fatigue demand was slightly higher. It was also demonstrated that the primary cause of fatigue damage was due to wave activity at the site. Analysis of low frequency response at the riser natural frequencies indicated...

... Abstract The objective of this paper was to evaluate the sensitivity of the natural frequency for an offshore wind turbine monopile in normally consolidated marine clay to different p-y models being used in practice: API RP 2GEO (2011) , which is the existing Recommended Practice for offshore...

... force natural frequency wave spectrum amplitude tubular element construction displacement amplitude equation axial dynamic behavior resonance frequency casing and cementing offshore technology conference Azpiazu , W. R. and Nguyen , V. N. , 1984 " Vertical Dynamics...

... and Serviceability Limit States (FLS and SLS) and generally the SLS requirements result in a conservative design from the ULS point of view. The structural natural frequency is important from the point of view of FLS. It is essential that resonance with the rotational frequency (1P) and the blade passing frequency...

... a cabled system or acoustic modem to transmit data to the surface. In addition, the significance of regional submerged currents for wellhead stress and fatigue is highlighted, as well as considerations for vibration mitigation. wellhead stress flagpole frequency prediction natural frequency bop...

... in this paper. model test amplitude frequency experimental model step riser configuration upstream oil & gas reynolds number axis offshore technology conference flexible riser coefficient current velocity natural frequency displacement vortex vibration test section Feng . C...

... conditions including idle, operating and emergency shutdown. The paper also describes the procedure that was used to estimate the system natural frequencies and mode shapes from the acceleration recordings. An assessment of the precision of the monitoring system is also provided with recommendations...

... motion component otc 23958 motion characteristic offshore technology conference field development natural frequency configuration upstream oil & gas natural period riser pontoon subsea system production riser frequency flexible dry tree semisubmersible drilling first-order...

... frequency renewable energy module wind energy jst constraint diameter transition piece optimization problem support structure substructure natural frequency offshore wind turbine outer diameter thickness batter artificial intelligence stiffness loading configuration turbine...

... frequency offshore technology conference loading platform design magnitude wind turbine caisson suction caisson natural frequency stiffness bhattacharya fmf wind energy arrangement turbine loading cycle foundation stiffness renewable energy owt otc 23058 upstream oil...

... vibrationsolutions are derived and solved using simple (e.g., MATLAB) programming. axial vibration vibration axial stress otc 23048 artificial intelligence viv unstable zone instability cross-flow viv amplitude fatigue analysis natural frequency ttr stability diagram tension fluctuation...

... Abstract Natural frequency monitoring of offshore platforms is a valuable tool forstructural integrity management. Online structural integrity monitoring assumeseven greater significance when platforms are highly susceptible to damage dueto environmental wave loading and fatigue processes...

... developed to virtually eliminate the shedding of vortices. frequency diameter suppressor circumferential length standard deviation viv bare riser otc 19161 displacement vibration natural frequency offshore technology conference drag coefficient model riser riser bobbin reynolds...

... the systems responses to wave excitation at a range of frequencies, the systems natural frequencies, and the standard deviations of the systems motions in each degree of freedom in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform...

.... If the frequency of the tones is coincident with the structural natural frequency of the equipment associated with the riser, large amplitude vibrations may be excited. This might lead to fatigue failure. This phenomenon is widespread on many systems. It affected the export riser system of the BP Schiehallion FPSO...

... between the calibrations. The natural frequency of the tubes was computed to be 2.36 Hz (first-mode bending - the second-mode natural frequency was 9.31 Hz). In these computations, the tubes were assumed to be simple supported, straight, and with constant tension, thus the computed natural frequencies...

... still water natural frequency), and the vertical axis is the normalized root-mean-square (rams) displacement to the pipe outside diameter, such that the maximum value in the data is unity. For the 2D fairings, the pipe s motion increases with the reduced velocity, exhibiting unstable behavior, while...