Comparison of two statistical wave models for fatigue and fracture analysis of ship structures

2019 ◽  
Vol 187 ◽  
pp. 106161 ◽  
Author(s):  
Luis De Gracia ◽  
Helong Wang ◽  
Wengang Mao ◽  
Naoki Osawa ◽  
Igor Rychlik ◽  
...  
2005 ◽  
Author(s):  
Pradeep K. Sensharma ◽  
Malcolm Willis ◽  
Aaron Dinovitzer ◽  
Nat Nappi

The use of doubler plates or ‘doublers’ has become routine for temporary ship repairs. It is the preferred method for ships’ structural repairs for plate corrosion due to its relative ease and low cost of installation over the more costly permanent welded plate insert repair. A lack of performance data and engineering design guidance are the reasons that repairs with doublers are currently considered only temporary. This objective of this study was to develop a set of guidelines for designing and applying doubler plate repairs to ship structures. The guidelines were established using the following criteria: various stress analyses, buckling strength, corrosion types and rates, weld types, and doubler plate fatigue and fracture assessment. Studying and understanding doubler plate repair performance by comparison to that of the primary hull performance allows critical operational decisions to be made with greater ease and confidence. However, the ultimate goal of this study was to establish the design and limitations on the applications of doubler plate repairs for surface ships.


Author(s):  
Agnes Marie Horn ◽  
Kenneth A. Macdonald

The motivation of this paper is to highlight the importance of the work carried out during the last decade by Prof. Haagensen and Prof. Berge at the Norwegian University of Science and Technology NTNU, with the aim to inspire and motivate young engineers to continue their important and valuable research within fatigue and fracture. This paper will focus on their historical contribution to the research within fatigue and fracture of offshore and ship structures. Stig Berge is a professor of Marine Technology at the Norwegian University of Science and Technology NTNU. He has spent his academic carrier focusing on fatigue of offshore and ship structures; he has published more than 70 papers and articles in well-known journals and conferences since 80’s. Per Jahn Haagensen is currently an Emeritus professor at Department of Mechanical Engineering and Logistic Faculty of Technology. He has spent his whole research carrier within fatigue and fracture related topics mainly for the offshore industry. He is especially known for the different fatigue improvement methods which have been developed since the 90’s. He has until recently been an active member of the International Institute of Welding (IIW). This article aims to present their main findings and conclusions from their long academic carrier. While the authors have strived to convey in a single paper an overview of the careers and important contributions, the Professors themselves may well have chosen to place a different emphasis on their work.


Author(s):  
Zheng Yi Ren ◽  
Qing Fen Li ◽  
Hai Tao Zhu ◽  
Hai-sheng Shu ◽  
Ping Long

2016 ◽  
Vol 57 (1) ◽  
pp. 65-89 ◽  
Author(s):  
M.R. Nanda Kumar ◽  
A. Ramachandra Murthy ◽  
Smitha Gopinath ◽  
Nagesh R. Iyer

Author(s):  
Wengang Mao ◽  
Fredhi Agung Prasetyo ◽  
Jonas W. Ringsberg ◽  
Naoki Osawa

In the maritime industry, fatigue failure is one of the most significant failure modes for ship structures. The fatigue damage in ship structures is mainly caused by the variation of wave loadings applied on ships, leading to variable structural stresses. Therefore, a reliable description of wave environments encountered during a ship’s service life is essential for accurate fatigue assessment of ship structures. Besides the wave scatter diagram provided by classification society rules, different statistical wave models have also been built up to model wave environments along arbitrary ship routes. The wave models could provide more specific wave environment for any chosen sailing routes of an individual ship. They may have the potential to be used for some practical applications, such as conceptual ship fatigue design, remaining fatigue life prediction when a ship plans to change its original trade region, and crack maintenance planning etc. Since the development of these models may be based on different sources, e.g. satellite measurements, hindcast data, buoys, etc., the reliability and consistence of wave generations from various wave models must be validated by the measured wave environments in order to be used for those practical applications. In this paper, waves generated from two different wave models, one based on hindcast data and one mainly on satellite data, are compared with measured wave environments encountered by a 2800 TEU container vessel on the North Atlantic route. These wave models are used in the calculation of the fatigue damage in the vessel. The results obtained using waves generated from the two wave models are compared with the fatigue damage calculated based on strain measurements in the ship. Recommendations for future development of the wave models and further investigation to make the applications more realistic for ship fatigue assessment are also presented.


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