Reliability-Based Fatigue Design Criteria For Offshore Structures Considering The Effect Of Inspection And Repair

1993 ◽  
Author(s):  
Torgeir Moan ◽  
G.O. Hovde ◽  
A.M. Blanker
Keyword(s):  
Offshore Structures ◽  
Design Criteria ◽  
Fatigue Design

scholarly journals A brief review of fatigue design criteria on offshore wind turbine support structures

2020 ◽  
Vol 15 (55) ◽  
pp. 302-315
Author(s):  
Paulo Mendes ◽  
José A.F.O. Correia ◽  
Abílio M.P. De Jesus ◽  
Bianca Ávila ◽  
Hermes Carvalho ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Wind Turbine ◽  
Influencing Factors ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Design Criteria ◽  
Design Phase ◽  
Offshore Wind Turbines ◽  
Fatigue Design

In this paper, a brief review of the main fatigue design criteria and some advanced fatigue approaches applied to offshore structures (e.g. offshore wind turbines) are presented. It is extremely important to understand the fatigue phenomenon and how it affects structures since offshore structures are constantly submitted to cyclic loading and corrosive attacks that aggravate the problem. All the influencing factors and approaches used during the design phase are also discussed.

Fatigue Design Criteria as Function of the Principal Stress Direction Relative to the Weld Toe

2008 ◽  
Author(s):  
Inge Lotsberg
Keyword(s):  
Principal Stress ◽  
Hot Spot ◽  
Stress Conditions ◽  
Design Criteria ◽  
International Institute ◽  
Proportional Loading ◽  
Principal Stress Direction ◽  
Fatigue Design ◽  
Stress Direction ◽  
Weld Toe

For fatigue design it is necessary to provide guidelines on how to calculate fatigue damage at weld toes based on S-N data when the principal stress direction is different from that of the normal direction to the weld toe. Such stress conditions are found at details in different types of plated structures. Some different fatigue criteria for these stress conditions are presented in design standards on fatigue design. Criteria used by the International Institute of Welding (IIW), Eurocode, British Standard and in the DNV standards have been assessed against some relevant fatigue test data presented in the literature. Only proportional loading conditions have been considered here. (By proportional loading is understood that the principal stress direction is kept constant during a load cycle). An alternative equation for calculation of an equivalent or effective stress range based on stress normal to the weld toe and shear stress at the weld toe has been proposed. The proposed methodology can be used for nominal S-N curves and it can be used together with a hot spot stress S-N curve with stresses read out from finite element analysis. The different design criteria are presented in this paper together with recommendations on analysis procedure.

Fatigue design criteria for tanks for dangerous goods

1997 ◽  
Vol 2 (3) ◽  
pp. 129-133
Author(s):  
Thomas Svensson ◽  
Hakan Torstensson
Keyword(s):  
Design Criteria ◽  
Dangerous Goods ◽  
Fatigue Design

Characteristic S-N Curves for Fatigue Design of Titanium Risers

2002 ◽  
Author(s):  
Knut O. Ronold ◽  
Stig Wa¨stberg
Keyword(s):  
Fatigue Test ◽  
Test Data ◽  
Base Material ◽  
Offshore Structures ◽  
Defect Size ◽  
Statistical Analyses ◽  
Stress Range ◽  
Fatigue Design ◽  
Range Interval ◽  
Lower Tolerance

A recommended practice for design of titanium risers is currently being developed as part of Det Norske Veritas’ series of standards and recommended practices for offshore structures. A recommendation is given herein for characteristic S-N curves for use in design of titanium risers against fatigue failure. As a basis for this recommendation, a set of statistical analyses of available fatigue test data have been carried out. Separate analyses have been carried out for base material and welds. The analysis results have been interpreted with respect to mean S-N curves as well as 97.7% lower tolerance bounds with 95% confidence. Characteristic S-N curves for base material and welds, which are not non-conservative with respect to these tolerance bounds, have been proposed. The paper presents the assumptions, the test data, the statistical analyses and their results, and the proposed characteristic S-N curves. The areas of application of the proposed curves are discussed with a particular view to stress range interval, material grade, weld position, temperature, and defect size.

Strength and Fatigue Performance of Steel Lazy Wave Risers With Change in Configuration Parameters

2019 ◽  
Author(s):  
Mayank Lal ◽  
Feng Wang ◽  
Xiaohua Lu ◽  
Abhilash Sebastian
Keyword(s):  
Deep Water ◽  
Parametric Study ◽  
Fatigue Performance ◽  
Design Criteria ◽  
Cost Assessment ◽  
Fatigue Design ◽  
Design Variables ◽  
Steel Catenary Risers ◽  
Normative Cost ◽  
The Impact

Abstract Steel Lazy wave risers are being increasingly used for deep water applications due to better strength and fatigue performance in the touchdown zone compared to steel catenary risers. Several parameters govern the design of steel lazy wave risers including the length of the catenary from hang-off to start of buoyancy section and the length of the buoyancy section. In this paper, a parametric study is performed to investigate the trends in strength and fatigue performance of steel lazy wave risers with change in configuration parameters. A normative cost assessment is also performed to show the impact of these design variables on overall cost of the system. Dynamic analysis is performed to check the change in strength and fatigue performance of steel lazy wave risers as the configuration parameters are changed. The results from the parametric study will assist in designing steel lazy wave risers which satisfy the strength and fatigue design criteria.

Fitness-for-Purpose Assessment of Encirclement Split-Tees

2002 ◽  
Author(s):  
S. Wheat ◽  
C. S. Jandu ◽  
D. N. Bramley ◽  
J. H. Liu
Keyword(s):  
High Pressure ◽  
Design Criteria ◽  
Plastic Collapse ◽  
Fitness For Purpose ◽  
Design Code ◽  
Gas Industry ◽  
Fatigue Design ◽  
The Uk ◽  
Transmission Pipelines

Hot tap tees of the full encirclement split tee design are currently used in the UK gas industry to provide connections onto existing high pressure gas transmission pipelines and above ground installations. The fitness-for-purpose of this type of tee is not covered by the UK design code for above ground gas installations, IGE/TD/9. A fitness-for-purpose methodology has been developed by Advantica Technologies to determine the integrity of the fitting and attachment welds. The fitness-for-purpose assessment addresses the following: • The compliance of the fitting to plastic collapse, shakedown and fatigue design criteria. • The integrity of the attachment welds onto the carrier pipe. • The use of Engineering Critical Assessments in conjunction with existing procedures to ensure overall integrity.

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