Fatigue Strength Assessment Analysis of Large Container Ship

2014 ◽  
Vol 602-605 ◽  
pp. 385-389 ◽  
Author(s):  
Feng Lei Han ◽  
Chun Hui Wang ◽  
An Kang Hu ◽  
Ya Chong Liu
Keyword(s):  
Fatigue Strength ◽  
Hot Spot ◽  
Direct Calculation ◽  
Linear Wave ◽  
Container Ship ◽  
Wave Loads ◽  
Wave Load ◽  
Strength Assessment ◽  
Fatigue Strength Assessment ◽  
Large Container

Fatigue assessments of container ship structures can be processed using various direct calculation approaches or various approaches of classification societies [1,2]. In this investigation, the fatigue strength assessment to the key positions of a 9200TEU container ship has been performed ,subjected to the rules of BV about fatigue strength specification of large container ships, based on design wave method and Miner fatigue cumulative damage theory analysis method. Wave loads have been computed using linear wave load calculation method based on three-dimensional potential flow theory. And the fatigue strength assessment of the typical hot spot structures has also been conducted based on a series of critical single design wave.

A Comparison of Direct Calculation Approaches Applied on the Fatigue Strength Assessment of a Panamax Container Ship

2012 ◽  
Author(s):  
Zhiyuan Li ◽  
Wengang Mao ◽  
Jonas W. Ringsberg
Keyword(s):  
Stress Response ◽  
Fatigue Strength ◽  
Fatigue Damage ◽  
Measurement Data ◽  
Direct Calculation ◽  
Container Ship ◽  
Calculation Methods ◽  
Strength Assessment ◽  
Strip Theory ◽  
Calculation Procedures

Today, it is common practice to carry out fatigue assessments of ship structures using direct calculation procedures. A direct calculation analysis of a ship’s fatigue strength involves hydrodynamic analysis, stress response evaluation followed by fatigue damage calculation. Many numerical codes are available for these types of analyses. They could yield different values in a fatigue life prediction because of the different degrees of complexity in the computation of the ship’s response. For example, hydrodynamic loads can be calculated using the strip theory or the panel method. The stress response to these loads can be computed using a beam theory or more advanced analyses, such as global and/or local finite element analyses. In a direct fatigue analysis for ship design, spectral methods have been dominating but there is a growing interest in time-domain fatigue damage calculation procedures. The objective of the current investigation is to compare four commonly used direct calculation methods against measurement data. The comparison is carried out by making a case study on a Panamax container ship on which full-scale measurements have been performed. The computational efforts involved in the application of the current direct calculation methods are compared and their applicability in ship fatigue design is discussed.

Fatigue Strength Assessment of the Cruciform Fillet Welded Joint Using Hot-spot Stress Approach

2005 ◽  
Vol 29 (11) ◽  
pp. 1488-1493 ◽  
Author(s):  
Chang-Sung Seok ◽  
Dae-Jin Kim ◽  
Jae-Mean Koo ◽  
Jung-Won Seo ◽  
Byeong-Choon Goo
Keyword(s):  
Fatigue Strength ◽  
Welded Joint ◽  
Hot Spot ◽  
Hot Spot Stress ◽  
Strength Assessment ◽  
Fatigue Strength Assessment

Full-Scale Measurements on Hull Response of a Large-Container Ship in Service

2006 ◽  
Author(s):  
Kenichiro Miyahara ◽  
Ryuju Miyake ◽  
Norikazu Abe ◽  
Atsushi Kumano ◽  
Masanobu Toyoda ◽  
...  
Keyword(s):  
High Harmonic ◽  
Bending Moment ◽  
Full Scale ◽  
Linear Wave ◽  
Container Ship ◽  
Wave Loads ◽  
Non Linear ◽  
Large Container ◽  
Probability Density Distributions

In order to investigate hull responses of post-Panamax container ships in the actual sea, full-scale measurements on hull responses of a post-Panamax container ship in service were conducted. In linear wave domain, the probability density distributions of hull responses obtained by full-scale measurements were compared with the Rayleigh distributions to check on the range of the applicability, and comparisons with the long-term distributions of the longitudinal stress obtained by full-scale measurements and the direct structural analyses based on the wave loads analyzed by using the linear 3D Rankine source method were made to verify the accuracy. In non-linear wave domain, the measured longitudinal stresses showed the asymmetry of vertical bending moment. The long-term distributions of hull responses, which have the high harmonic components, obtained by full-scale measurements were compared with the numerical results analyzed by using non-linear methods to investigate the non-linearity on hull responses of container ship.

Uncertainty Modeling for Fatigue Strength Assessment of Welded Structures

1998 ◽  
Vol 120 (2) ◽  
pp. 97-102 ◽  
Author(s):  
W. Fricke ◽  
A. Mu¨ller-Schmerl
Keyword(s):  
Fatigue Strength ◽  
Hot Spot ◽  
Offshore Structures ◽  
Fatigue Tests ◽  
Published Data ◽  
Hot Spot Stress ◽  
Total Uncertainty ◽  
Strength Assessment ◽  
Characteristic Values ◽  
Fatigue Strength Assessment

The results of fatigue tests are characterized by much scatter. Such scatter is further increased if data from different test series are combined to derive, for instance, characteristic values for individual types of welded joints used in codes. Characteristic values are normally applied to the design of fatigue-resistant ship and offshore structures in connection with the nominal stress approach using S-N curves. More advanced approaches such as the hot-spot stress approach and the notch stress approach are applied to an increasing extent. Such approaches explicitly consider certain influence factors and allow the scatter of these factors to be treated individually. This way, probably even the total uncertainty can be reduced. After reviewing the different approaches used for fatigue strength assessment, the sources of scatter are addressed and assigned to factors considered in the different approaches. Based on published data of fatigue tests and imperfections observed in real structures, an attempt is made to quantify the uncertainties of the different factors and to draw conclusions for their individual consideration in the approaches mentioned.

Fatigue Strength Assessment of Crack Flaws in Thick High Tensile Steel Plates on Large Ships

2015 ◽  
Author(s):  
Yu Tian
Keyword(s):  
Fatigue Strength ◽  
Crack Growth ◽  
High Strength ◽  
Fatigue Performance ◽  
Container Ship ◽  
Near Surface ◽  
Strength Assessment ◽  
Deck Plate ◽  
Steel Grades ◽  
Fatigue Strength Assessment

The sizes of large container ship increased during the past years have accompanied by the use of thicker plate and higher steel grade. The fatigue performance of thick high strength steel plate is a problem which has to be investigated. As an example, the fatigue crack growth of the butt welds at the deck plate of a 8530 TEU container ship has been investigated. Crack growth life predication method in combination with failure assessment diagram (FAD) technology has been used to calculate the fatigue life and the critical crack length. It has been discussed the fatigue sensitivity of the steel grades, the plate thicknesses and the positions of initial defect in thickness direction. The FAD methodology used in this paper is a common approach which has been introduced in various standards, which is practical and useful in fatigue strength assessment of ship structures. Crack tip opening displacement (CTOD) tests of high tensile steel YP40 and YP 47 have been carried out to obtain the fracture toughness, which play an important role in FAD calculation. And the minimum value of the test results is used as the calculated value. It is concluded that the fatigue performance of high strength steels do not increase proportionally with the steel grades and plate thicknesses. The calculation results also have shown that there is significant decrease of fatigue performance along with the increase of plate thickness, and in the same initial conditions, the harmfulness of the near surface defects on structure detail is more serious compared to the embedded defects.

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