Full Stochastic Fatigue Analysis for Kizomba ‘A’ FPSO-Hull Interface Design

2003 ◽  
Author(s):  
Jeong Heon Na ◽  
In Hye Lee ◽  
Woo Seung Sim ◽  
Hyun Soo Shin
Keyword(s):  
Interface Design ◽  
Hot Spot ◽  
Global Analysis ◽  
Model Analysis ◽  
Fatigue Analysis ◽  
Point Of View ◽  
Sea State ◽  
Hot Spot Stress ◽  
Tower Foundation ◽  
Long Operation

As the offshore oilfields shift into the deeper ocean of less infra, FPSOs become a popular solution. Many FPSOs operate in fields where they are expected to stay for decades without drydocking for maintenance. Currently one of the most active area of the FPSO installation is the west Africa offshore where the sea state is benign and the swell from the south is dominant and the water depth is deep. In the case of long operation in the benign site, the fatigue is rather important in the structural design point of view. This paper describes the first extensive practical application of the full stochastic fatigue analysis method to the design of the FPSO-hull interface design like topside supports, flare tower foundation, riser porches, caissons, crane pedestals, mooring foundations, helideck connections, deck penetrations and etc. Especially, topside support is highlighted in detail because of its potential inertia loading due to heavy weight and importance in fabrication stage. The full length of Kizomba ‘A’ FPSO being built in Hyundai Heavy Industries is modeled for the global analysis and the boundary conditions from the global model analysis are transferred for the local model analysis. Some discussions of screening analysis and hot spot stress calculation and roll damping evaluation are also presented.

Applicability Evaluation of SS (Structural Stress) Method on Actual Project

2008 ◽  
Vol 580-582 ◽  
pp. 633-636 ◽  
Author(s):  
Kwang Seok Kim ◽  
Joong Kyoo Kang ◽  
Joo Ho Heo ◽  
Sung Geun Lee
Keyword(s):  
Fatigue Life ◽  
Hot Spot ◽  
Fatigue Analysis ◽  
Correlation Factor ◽  
Structural Stress ◽  
Hot Spot Stress ◽  
Notch Stress ◽  
Loading Case ◽  
Application Data ◽  
Applicability Evaluation

The structural stress (SS) method developed by BATTELLE has been studied based on small or mid-size scale specimens. In order to apply the new method, such as SS, on an actual project, it should have application results on actual project. However, SS method didn’t have a lot of application data compared to class procedure using hot spot stress (HSS). In order to find out whether the SS method, for the evaluation of fatigue life, can give reasonable results when it is applied under the same loading suggested by classification societies, it was compared with fatigue lives derived by class. ABS & DNV’s simplified fatigue analysis method were adopted to check the validity of SS method. Before applying complicated loading of class, static loading case was applied, since the class method has their own correlation factor for wave loading. And then, simplified fatigue analysis was performed with more complicated loading cases. From the results of fatigue life calculation, it can be said that SS shows reasonable fatigue lives with respect to HSS or notch stress based fatigue lives.

Automated Identification of Critical Tubular Joints of Offshore Jacket Structure by Deterministic Fatigue Analysis

2017 ◽  
Author(s):  
Shrikarpagam Dhandapani
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Hot Spot ◽  
Offshore Structures ◽  
Fatigue Analysis ◽  
Optimized Design ◽  
Base Shear ◽  
Hot Spot Stress ◽  
Environmental Loads ◽  
Tubular Joints

Fatigue occurs in structures due to the stresses from cyclic environmental loads. Offshore environmental loads being highly cyclic and recurring in nature, fatigue analysis with high degree of accuracy is required for reliable and optimized design of offshore structures. The main aim of this paper is to automate the process of identification of fatigue critical tubular joints of an offshore jacket structure using deterministic fatigue analysis with emphasis on the Hot Spot Stress Range (HSSR), an important measure in estimating fatigue damage, calculated using three different approaches for each tubular joint. The first approach determines HSSR at the time of maximum base shear of the jacket, the second, by calculating the difference between maximum and minimum Hot Spot Stress (HSS) and the third, at all time-instants of the wave cycle. Thus fatigue damage and fatigue life of the tubular joints are estimated using the highest HSSR value and the joints with lower fatigue life are identified as fatigue sensitive joints. This ensures effective identification of critical tubular joints of the offshore jacket structure which needs detailed investigation or redesign for fatigue. The deterministic approach discussed in this paper is applicable to large jackets which contains more number of tubular joints where sophisticated fatigue assessment at the preliminary stage is computationally intensive and manual identification of fatigue critical joints is laborious.

Fatigue Analysis of a Thin Cover Plate Structure in a Light Craft

2015 ◽  
Author(s):  
Till Köder ◽  
Berend Bohlmann
Keyword(s):  
Hot Spot ◽  
Gas Metal Arc Welding ◽  
Plate Thickness ◽  
Fatigue Analysis ◽  
Fatigue Tests ◽  
Cover Plate ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Notch Stress ◽  
Metal Arc Welding

Experimental fatigue analysis of a fillet-welded cover plate detail (‘floating frame’) of small and light craft was carried out at Kiel University of Applied Sciences. The structural detail is an intersection of longitudinal deck stiffener and transverse web frame with a plate thickness of 3.5mm and a doubling length of 100mm. Manual gas metal arc welding was used for the production of the 46mm long transverse fillet welds. The load-controlled constant amplitude fatigue tests at stress ratio R = 0 were supported by 3D finite-element analysis based on laser scans of the weld seams. Structural hot-spot stress, stress linearisation and Xiao and Yamada’s 1mm geometrical stress approaches were applied to the specimens as well as the notch stress concept with reference radii rref = 0.05mm and 1.00mm.

Applicability Evaluation of SS (Structural Stress) Method on Actual Project

2007 ◽  
Author(s):  
Kwang-Seok Kim ◽  
Joong-Kyoo Kang ◽  
Joo-Ho Heo ◽  
Sung-Geun Lee
Keyword(s):  
Fatigue Life ◽  
Hot Spot ◽  
Fatigue Analysis ◽  
Correlation Factor ◽  
New Method ◽  
Structural Stress ◽  
Hot Spot Stress ◽  
Notch Stress ◽  
Loading Case ◽  
Application Data

The structural stress (SS) method developed by BATTELLE has been studied based on small or mid size scale specimens. In order to apply new method on actual project, the new method such as SS should have application results on actual project. However, SS method didn’t have a lot of application data compared to class procedure using hot spot stress (HSS). In order to find that the SS method for the evaluation of fatigue life can give reasonable results when it is applied under the same loading suggested by classification societies, fatigue lives derived by class and SS method were compared. ABS & DNV’s simplified fatigue analysis method were adopted to check the validity of SS method. Before applying complicated loading of class, static loading case was applied since the class method has their own correlation factor for wave loading. And then simplified fatigue analysis was performed with more complicated loading cases. From the results of fatigue life calculation, it can be said that SS shows reasonable fatigue lives with respect to HSS or notch stress based fatigue lives.

Hot spot stress investigation on rib-to-deck-to-floor beam connections in UHPC reinforced OSDs

2021 ◽  
Vol 179 ◽  
pp. 106517
Author(s):  
Bin Cheng ◽  
Hesham Abdelbaset ◽  
Liang Tian ◽  
Hai-Ting Li ◽  
Qingtian Su
Keyword(s):  
Hot Spot ◽  
Hot Spot Stress

Experimental comparison in hot spot stress between CFCHS and CHS K-joints with gap

2008 ◽  
pp. 389-395 ◽  
Author(s):  
L Tong ◽  
C Sun ◽  
Y Chen ◽  
X Zhao ◽  
C Liu ◽  
...  
Keyword(s):  
Hot Spot ◽  
Experimental Comparison ◽  
Hot Spot Stress
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