Simplified Fatigue Design Procedure For Offshore Structures

1986 ◽  
Author(s):  
J.F. Geyer ◽  
B. Stahl
Keyword(s):  
Design Procedure ◽  
Offshore Structures ◽  
Fatigue Design

scholarly journals A Study of Fatigue Design Procedure for Tubular Connections of Offshore Structures

1980 ◽  
Vol 1980 (148) ◽  
pp. 274-283
Author(s):  
Kunihiro Iida ◽  
Kohzoh Asano ◽  
Masatsugu Toyofuku ◽  
Kuniteru Ishikawa
Keyword(s):  
Design Procedure ◽  
Offshore Structures ◽  
Fatigue Design

scholarly journals Model fatigue test result of welded structural element and proposal for fatigue design procedure

1991 ◽  
Vol 1991 (170) ◽  
pp. 723-735
Author(s):  
Ryuichi Nagamoto ◽  
Masaaki Matoba ◽  
Tetsuro Kawasaki ◽  
Katsuaki Inoue ◽  
Tohru Hori ◽  
...  
Keyword(s):  
Fatigue Test ◽  
Design Procedure ◽  
Structural Element ◽  
Fatigue Design ◽  
Test Result

Very Large Floating Structures

2007 ◽  
Author(s):  
H. Suzuki ◽  
H. R. Riggs ◽  
M. Fujikubo ◽  
T. A. Shugar ◽  
H. Seto ◽  
...  
Keyword(s):  
Design Procedure ◽  
Offshore Structures ◽  
Floating Structure ◽  
Floating Structures ◽  
Design Procedures ◽  
Novel Technology ◽  
Hydroelastic Analysis ◽  
Behavior Design ◽  
Hydroelastic Response ◽  
Near Future

Very Large Floating Structure (VLFS) is a unique concept of ocean structures primary because of their unprecedented length, displacement cost and associated hydroelastic response. International Ship and Offshore Structures Congress (ISSC) had paid attention to the emerging novel technology and launched Special Task Committee to investigate the state of the art in the technology. This paper summarizes the activities of the committee. A brief overview of VLFS is given first for readers new to the subject. History, application and uniqueness with regard to engineering implication are presented. The Mobile Offshore Base (MOB) and Mega-Float, which are typical VLFS projects that have been investigated in detail and are aimed to be realized in the near future, are introduced. Uniqueness of VLFS, such as differences in behavior of VLFS from conventional ships and offshore structures, are described. The engineering challenges associated with behavior, design procedure, environment, and the structural analysis of VLFS are introduced. A comparative study of hydroelastic analysis tools that were independently developed for MOB and Mega-Float is made in terms of accuracy of global behavior. The effect of structural modeling on the accuracy of stress analysis is also discussed. VLFS entails innovative design methods and procedure. Development of design criteria and design procedures are described and application of reliability-based approaches are documented and discussed.

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.

Assessment of Fatigue Damage of Floating Fish Cages Due to Wave Induced Response

2009 ◽  
Author(s):  
Paul E. Thomassen ◽  
Bernt J. Leira
Keyword(s):  
Structural Analysis ◽  
Fatigue Damage ◽  
Design Procedure ◽  
Irregular Waves ◽  
Induced Response ◽  
Fish Farms ◽  
Analysis And Design ◽  
Drag Forces ◽  
Fatigue Design ◽  
Fish Cages

Floating fish cages provide the main production utilities for salmon farming. However, despite their pivotal role in production safety as well as in protection of the environment, there is still much room for improvement in relation to verified structural design procedures and computerized tools for structural analysis. To a large extent they can be regarded as not being in accordance with the state-of-the-art of structural analysis and design for more traditional types of marine structures. In this paper a study of fatigue design for floating fish farms is presented. The study is based on a structure which is being applied by the Norwegian fish farming industry today. The floater is made of steel cylinders which are configured as a square. The formulation for the wave loading is based on a combination of potential theory and horizontal drag forces on the floater. Horizontal and vertical drag forces on the netpen are also accounted for. A fatigue design procedure for floating fish farms in steel is suggested. The procedure is based on a time domain analysis of the structure in irregular waves. For each seastate half an hour (real time) analysis is performed and the stress history for an assumed critical location is computed. Based on the stress histories, the fatigue damage is estimated by application of rain flow counting and a given SN curve. The scatter diagram for the seastates at a given location is generated from the associated wind speed distribution.

Water Deluge System Design for Fire Fighting

2016 ◽  
Author(s):  
Jin Lee ◽  
Sang Hwan Kim ◽  
Jung Kwan Seo ◽  
Jeom Kee Paik
Keyword(s):  
Fluid Dynamic ◽  
Design Procedure ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Probabilistic Sampling ◽  
Spray System ◽  
Safety Design ◽  
Fire Scenarios ◽  
Fire And Explosion ◽  
The Cost

The ships and offshore structures are exposed to inherently the risk of fire and explosion. These fire and explosion, accident caused by grave consequences not only to the ships and offshore platforms on the sea but the environment all mankind. The aim of this paper is to focus on an optimization of water deluge and mist spray system locations subjected to jet on the ships and offshore platforms. A trustworthy set of fire scenarios is identified and classified using probabilistic sampling methods calling for Latin Hyper Sampling. These events of fire are numerically calculated for selected scenarios by the computational Fluid Dynamic (CFD) code using a KFX. The Water Deluge Location Index (WLI) is then calculated by using the frequency and consequence of fire scenarios. And then, WLI are utilized to prioritize the optimal locations of water deluge and mist spray systems. The recommended methodology believes that can increase to certainties in the design procedure of unreliability and can regard the cost-effectiveness of safety design.

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