Numerical implementation for fatigue assessment of butt joint improved by high frequency mechanical impact treatment: A structural hot spot stress approach

2016 ◽  
Vol 92 ◽  
pp. 211-219 ◽  
Author(s):  
Caiyan Deng ◽  
Yong Liu ◽  
Baoming Gong ◽  
Dongpo Wang
Keyword(s):  
High Frequency ◽  
Hot Spot ◽  
Butt Joint ◽  
Numerical Implementation ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Mechanical Impact

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).

Qualification of the Notch Stress Approach for the Fatigue Assessment of Welded Pressure Equipment and Power Plant Components

2017 ◽  
Author(s):  
Jürgen Rudolph ◽  
Ralf Trieglaff ◽  
René Stößlein ◽  
Fabian Hauser
Keyword(s):  
Test Data ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Hot Spot ◽  
Pressure Vessels ◽  
Assessment Procedure ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Notch Stress

The fatigue assessment of welded joints in different engineering disciplines is usually based on nominal, structural or notch stresses on one hand (elastic concept using component fatigue curves of load controlled test data) and local strains on the other hand (elasto-plastic concept using material fatigue curves of strain-controlled push-pull test data of un-notched and polished standard specimens). The concepts of the first mentioned group are implemented in widespread standards and recommendations such as [1] to [3]. The fatigue assessment procedure of the European standard for unfired pressure vessels (EN 13445-3, Clause 17 & 18 and related annexes) [4] is currently under revision with one focus on the elaboration of user friendly fatigue assessment options for welded components [5]. The current state of the art focuses on the application of an adapted structural hot spot stress approach to the fatigue assessment of welded pressure equipment [5]. Although this is a significant step forward, the implementation of a notch stress approach can furtherly increase the fatigue assessment options by detailed weld seam analysis. The paper focuses on respective methodological proposals and application examples of typical welded joints. The finite element analysis as part of the procedure has to be harmonized with the requirements of the assessment procedure. Of course, the compatibility of the hot spot stress approach and a notch stress approach has to be guaranteed for individual examples. The direct comparison of the different approaches allows for a qualitative evaluation of methods. The application of an appropriate master fatigue curve FAT100 and the limitations with regard of stress/strain ranges in the low cycle fatigue (LCF) regime as well as the fatigue assessment of welded joints with mild weld toe notches is the subject of special considerations. The latest recommendations of German Welding Society (DVS) [6] constitute a reference for the last two subjects raised.

scholarly journals Definition of hot spot Stress in welded structure for fatigue assessment (2nd Report)

1991 ◽  
Vol 1991 (170) ◽  
pp. 705-721
Author(s):  
Susumu Machida ◽  
Masaaki Matoba ◽  
Hitoshi Yoshinari ◽  
Ryuichi Nishimura
Keyword(s):  
Hot Spot ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Welded Structure ◽  
Definition Of

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.

Fatigue assessment of a steel truss bridge based on multi-dimensional finite element modelling

2021 ◽  
Author(s):  
Kris Hectors ◽  
Hans De Backer ◽  
Lien Saelens ◽  
Wim De Waele
Keyword(s):  
Finite Element ◽  
Decision Support ◽  
Finite Element Modelling ◽  
Hot Spot ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Railway Bridges ◽  
Element Modelling ◽  
Railway Traffic ◽  
Steel Truss Bridge

<p>This paper presents a multidimensional finite element modelling approach for the fatigue assessment of welded railway bridges based on a case study of a railway bridge in Belgium. The nominal stress approach of Eurocode 3 is compared to a hot spot stress based fatigue life calculation for the standardized fatigue load models for railway traffic. Hot spot stresses are calculated with an in-house developed framework that allows automated determination of hot spot stresses. It is discussed how this work can fit in a larger decision support system in the scope of structural health monitoring. The presented approach proves to be better for decision support compared to the conventional approach in the Eurocode.</p>

Fatigue of Ship Structural Details—Technical Development and Problems

1997 ◽  
Vol 41 (04) ◽  
pp. 318-331
Author(s):  
Tao Xu
Keyword(s):  
Fatigue Damage ◽  
Hot Spot ◽  
Fatigue Loading ◽  
Technical Development ◽  
Fatigue Reliability ◽  
Random Loading ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Technical Developments ◽  
Structural Details

During the past five years, a joint industry-government sponsored research project titled the Ship Structural Maintenance Project (SMP) has been conducted at the Department of Naval Architecture & Offshore Engineering, University of California at Berkeley. As a part of this project, the fatigue damage of ship structural details has been extensively studied. This paper summarizes the technical development in fatigue assessment of ship structural details developed during this project. In the fatigue resistance model, the fatigue damage evaluation of structural details was based on a stress range/number-of-cycles-to-failure (SN) approach in which the nominal stress procedure and the hot spot stress procedure were employed. The fatigue assessment of cracked structural details was based on a cracked SN approach developed by a hybrid SN-FM (fracture mechanics) methodology. This cracked SN approach was further developed to incorporate load-shedding effects. In the fatigue loading model, a new formula for the damage correction factor associated with a wide-banded load process was developed. The random loading sequence for ship service was addressed. Fatigue reliability models were then reviewed and the different fatigue reliability updating procedures were evaluated. These techniques were employed in the fatigue analysis of structural details in three tankers. Analysis results from these three ships were presented to illustrate the technical developments and problems associated with fatigue assessment of ship structural details.

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