scholarly journals On the performance of monopile weldments under service loading conditions and fatigue damage prediction

2021 ◽  
Author(s):  
Romali Biswal ◽  
Abdullah Al Mamun ◽  
Ali Mehmanparast
Keyword(s):  
Fatigue Damage ◽  
Loading Conditions ◽  
Damage Prediction ◽  
Service Loading

Analysis of Residual, Thermal, and Loading Stresses in a B33 Wheel and Their Relationship to Fatigue Damage

1967 ◽  
Vol 89 (2) ◽  
pp. 249-258 ◽  
Author(s):  
J. P. Bruner ◽  
G. N. Benjamin ◽  
D. M. Bench
Keyword(s):  
Fatigue Damage ◽  
Fatigue Tests ◽  
Loading Conditions ◽  
Test Results ◽  
Iron And Steel ◽  
Service Loading ◽  
Stress Patterns ◽  
Resultant Stress ◽  
Superposition Principles ◽  
Made In

The current General Electric computer study sponsored by The American Iron and Steel Institute, discussed at the ASME Railroad Division 1965 Winter Meeting, has the objective of determining the most favorable geometric configuration to minimize service stresses. This present investigation involves the corollary problem of service loading conditions that produce the highest stresses and the possibility of fatigue damage. Static loading, rim heating, residual stress measurements, and fatigue tests were made in the laboratory on representative B33 wheels. A series of simulated loading conditions was studied and the resulting stresses combined by simple superposition principles. The resultant stress patterns were compared with fatigue test results using the modified Goodman relationship. In this way the service loading conditions that produce fatigue damage may be predicted.

scholarly journals Location-based fatigue damage assessment on an FPSO by the spectral analysis method

2019 ◽  
Vol 272 ◽  
pp. 01019
Author(s):  
A Viswanathan ◽  
V A Subramanian ◽  
D Kumar
Keyword(s):  
Transfer Function ◽  
Fatigue Damage ◽  
Stress Transfer ◽  
Bending Moment ◽  
Spectral Density Function ◽  
Structural Member ◽  
Offshore Platforms ◽  
Loading Conditions ◽  
Analysis Method ◽  
Damage Prediction

Floating production storage and offloading ships (FPSOs) are offshore platforms positioned at a location and operating at different loading conditions and corresponding draughts. Due to their static location, they get subjected to continuous fluctuating loads due to the sea environment. For these reasons the fatigue damage prediction of an FPSO is essential. The emphasis of this study is on the effect of fatigue damage at critical joints of critical structural members under the influence of vertical and horizontal bending in isolation and combination. The method considers an FPSO of 320m length for a case study, selecting a total of fourteen such structural member locations along the periphery at its midship section. The analysis considers two necessary loading conditions namely, fully loaded and ballast condition. The study uses spectral fatigue analysis method wherein the bending moment transfer function generates the stress transfer function, which in turn helps to generate the power spectral density function. Combining the spectral moments with Palmgren-Miner rule gives the cumulative fatigue damage of the FPSO. The results provide an insight into the variation in fatigue damage concerning the location of the structural member under the influence of vertical and horizontal bending moments.

On the Vortex-Induced Vibration Response of a Model Riser and Location of Sensors for Fatigue Damage Prediction

2010 ◽  
Author(s):  
C. Shi ◽  
L. Manuel ◽  
M. A. Tognarelli ◽  
T. Botros
Keyword(s):  
Fatigue Damage ◽  
Traveling Waves ◽  
Wavelet Transforms ◽  
Cross Flow ◽  
Waveform Analysis ◽  
Flexible Cylinder ◽  
Vortex Induced Vibration ◽  
Damage Prediction ◽  
Time Frequency ◽  
Damage Rate

This study is concerned with vortex-induced vibration (VIV) of deepwater marine risers. Riser response measurements from model tests on a densely instrumented long, flexible riser in uniform and sheared currents offer an almost ideal set-up for our work. Our objectives are two-fold: (i) we use the measured data to describe complexities inherent in riser motions accompanying VIV; and (ii) we discuss how such data sets (and even less spatially dense monitoring) can be used effectively in predicting fatigue damage rates which is of critical interest for deepwater risers. First, we use mathematical tools including Hilbert and wavelet transforms to estimate instantaneous amplitudes and phases of cross-flow (CF) and in-line (IL) displacements for the model riser as well as scalograms to understand time-frequency characteristics of the response; this work confirms that the motion of a long flexible cylinder is far more complex than that of a rigid cylinder, and that non-stationary characteristics, higher harmonics, and traveling waves are evident in the riser response. Second, a well-established empirical procedure, which we refer to as Weighted Waveform Analysis (WWA), is employed to estimate the fatigue damage rate at various locations along the length of the riser from strain measurements at only eight sensors. By iterating over numerous different combinations of these eight strain sensors as inputs (from among all the twenty-four available locations on the riser), optimal locations for the eight sensors on the riser are identified by cross-validation, whereby predicted strains and fatigue damage rates at locations of instrumented sensors are compared with strains and fatigue damage rates based on actual recorded measurements there. We find that, if properly placed, as few as eight sensors can provide reasonably accurate estimates of the fatigue damage rate over the entire riser length. Finally, we demonstrate how more accurate fatigue damage prediction can result when non-stationary response characteristics are considered and a modified WWA method (that more effectively accounts for traveling waves than the WWA method alone does) is employed.

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