Fatigue Assessment of Ship Structures using Hot Spot Stress and Structural Stress Approaches with Experimental Validation

2008 ◽  
Author(s):  
Myung Hyunn Kim ◽  
Seong Minn Kim ◽  
Jae Myung Lee ◽  
Sung Wong Kang
Keyword(s):  
Experimental Investigation ◽  
Experimental Validation ◽  
Hot Spot ◽  
Initial Study ◽  
Systematic Investigation ◽  
Structural Stress ◽  
Ship Structures ◽  
Gusset Plates ◽  
Hot Spot Stress ◽  
Fatigue Assessment

The aim of this study is to investigate fatigue assessment of typical ship structures employing structural stress approach and to compare with hot spot stress approach. As an initial study of the systematic validation efforts on structural stress method, an experimental investigation is performed on a series of edge details with welded gusset plates. Extrapolation based hot spot stress using converged mesh were also calculated for each specimen types. Having validated the application of structural stress for small edge details, a systematic investigation is carried out for a fatigue assessment of typical ship structures employing structural stress approach. Fatigue strength of side shell connection of a 8,100 TEU container vessel is evaluated using hot spot stress and structural stress employing simplified fatigue analysis.

A comparative study for the fatigue assessment of a ship structure by use of hot spot stress and structural stress approaches

2009 ◽  
Vol 36 (14) ◽  
pp. 1067-1072 ◽  
Author(s):  
Myung Hyun Kim ◽  
Seong Min Kim ◽  
Young Nam Kim ◽  
Sung Geun Kim ◽  
Kyoung Eon Lee ◽  
...  
Keyword(s):  
Comparative Study ◽  
Hot Spot ◽  
Structural Stress ◽  
Hot Spot Stress ◽  
Ship Structure ◽  
Fatigue Assessment

A Case Study Comparison of Surface Extrapolation and Battelle Structural Stress Methodologies

2004 ◽  
Author(s):  
Brian E. Healy
Keyword(s):  
Convergence Analysis ◽  
Hot Spot ◽  
Structural Stress ◽  
Hot Spot Stress ◽  
Side Shell

A case study comparison of the surface extrapolation and Battelle structural stress methodologies has been performed on a side shell connection detail typical of a representative FPSO or tanker vessel. Computations of hot spot stress via either method are consistent with current recommended practice. Convergence analysis to determine the hot spot stresses that best serve as fatigue parameters and a fatigue comparison that employs hot spot stresses from the convergence analysis have been executed at various locations around the detail. Results are reported and discussed.

Advanced Integrated Design Method for Fatigue Assessment of Large Elastic Ship Structures

2013 ◽  
Vol 371 ◽  
pp. 443-447
Author(s):  
Ionica Rubanenco ◽  
Iulia Mirciu ◽  
Leonard Domnisoru
Keyword(s):  
Service Life ◽  
Hot Spot ◽  
Ratio Method ◽  
Wave Loads ◽  
Ship Structures ◽  
Fatigue Assessment ◽  
Integrated Method ◽  
Oscillation Analysis ◽  
Non Linear ◽  
Wave Induced

This paper is focused on an advanced method for ship structures fatigue assessment. The ships classification societies standard rules for fatigue analysis are based on simplified procedures, with wave induced loads obtained by linear oscillation analysis (low frequency, around 0.1 Hz), or equivalent statistical wave loads. In the case of large elastic ship structures, with hull length over 150 m, the global wave induced vibration response (high frequency, around 1 Hz) becomes significant. The developed integrated method for large ships fatigue assessment includes three interlinked analyses, as follows: the hot-spot stresses evaluation by 3D finite element models, wave induced loads by short term linear and non-linear hydroelastic dynamic analysis, ship service life and fatigue assessment by damage cumulative ratio method. As testing ship, it is considered a double hull LPG Liquefied Petroleum Gas carrier, with total length 239 m, for a set of structural details with stress hot-spots. Based on the non-linear hydroelastic wave loads, the integrated method of fatigue assessment becomes more accurate, predicting for the amidships structure 14 years of ship service life, instead of over 20 years according to the rules standard approach, so that the confidence on ship structure fatigue evaluation can be increased in the design process.

Fatigue Assessment of Trimaran Structure Based on Simplified Procedure

2012 ◽  
Vol 525-526 ◽  
pp. 333-336
Author(s):  
Hui Long Ren ◽  
Shehzad Khurram ◽  
Chun Bo Zhen ◽  
Khurram Asifa
Keyword(s):  
Fatigue Damage ◽  
High Speed ◽  
Hot Spot ◽  
Mathematical Formulation ◽  
Direct Calculation ◽  
Assessment Procedure ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Strength Assessment ◽  
Simplified Procedure

In recent years, Trimaran platform design has got the attention of naval architects owing to its superior seagoing performance. Trimaran structure experiences severe loads due to its unique configuration and high speed, causing stress concentration, especially in cross deck region and accelerate fatigue damage. This paper presents fatigue strength assessment of Trimaran structure by simplified procedure. A methodology is proposed to evaluate fatigue loads and loading conditions by load combinations of direct calculation procedure of Lloyds Register Rules for Classification of Trimaran (LR Rules). Global FE analysis, in ANSYS, is performed to investigate the stress response. The stress range is computed by hot-spot stress approach, and its long term distribution is specified by Weibull distribution. Fatigue damage of selected critical details is calculated using mathematical formulation of simplified fatigue assessment procedure of Common Structure Rules (CSR).

Fatigue of Tubular Joints: Hot Spot Stress Method Revisited

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Pingsha Dong ◽  
Jeong K. Hong
Keyword(s):  
Hot Spot ◽  
Life Assessment ◽  
Structural Stress ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Section Viii ◽  
Remaining Life Assessment

A series of well-known tubular joints tested in UKSORP II have been re-evaluated using the mesh-insensitive structural stress method as a part of the on-going Battelle Structural Stress JIP efforts. In this report, the structural stress based analysis procedure is first presented for applications in tubular joints varying from simple T joints, double T Joints, YT joints with overlap, and K joints with various internal stiffening configurations. The structural stress based SCFs are then compared with those obtained using traditional surface extrapolation based hot spot stress methods. Their abilities in effectively correlating the fatigue data collected from these tubular joints are demonstrated. These tests are also compared with the T curve typically used for fatigue design of tubular joints as well as the structural stress based master S-N curve adopted by ASME Section VIII Div 2. Finally, some of the implications on fracture mechanics based remaining life assessment for tubular joints are discussed in light of the results obtained in this investigation.

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