Review of Defect Distributions for Probabilistic Structural Integrity Assessment

2002 ◽  
Author(s):  
W. Zhao ◽  
A. Stacey
Keyword(s):  
Future Development ◽  
Structural Integrity ◽  
Assessment Methods ◽  
Considerable Variability ◽  
Welded Structures ◽  
Defect Distribution ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Considerable Research ◽  
The Subject

The defect distribution is a particularly important parameter in the application of probabilistic defect assessment methods to the integrity assessment of welded structures. However, the subject is complex and, despite considerable research efforts in this area and the availability of a significant body of data, this defect distribution is subject to considerable variability and uncertainty. This paper reviews the data in the literature, providing a status review of defect distributions and the identification of areas requiring further investigation, with a view to assisting with the future development of probabilistic defect assessment methods.

Improvements to the Fracture Assessment of Welds Using FITNET Fitness for Service Assessment Procedure

2005 ◽  
Author(s):  
Mustafa Koc¸ak ◽  
Eduard Seib ◽  
Afshin Motarjemi
Keyword(s):  
Laser Beam ◽  
Structural Integrity ◽  
High Strength ◽  
Assessment Procedure ◽  
Welded Structures ◽  
Integrity Assessment ◽  
Friction Stir ◽  
Funded Project ◽  
Aluminum And Magnesium Alloys ◽  
Welding Processes

Recent developments of the advanced welding processes such as laser beam welding (LBW), solid state friction stir welding (FSW) and hybrid welding, numbers of advanced structures are being designed and constructed in industries such as aerospace, power generation, oil and gas transmission and transportation. Development of new structural aluminum and magnesium alloys as well as high strength steels provide further possibilities for the welded structures in similar and dissimilar (material-mix) configurations. Consequently, there is an increasing demand for “Fitness-for-Service” (FFS) assessment of those advanced welded structures by considering the specific features of these weld joints (such as narrow weld width, high strength mis-match, etc.). In year 1999, Structural Integrity Assessment Procedure SINTAP has been developed for analysis of flaws to avoid fracture within the European Commission funded project SINTAP. Recently, the European Community funded project FITNET in the form of a Thematic Network (TN) organisation has started to review the existing FFS procedures and develop an updated, unified and verified European FITNET FFS Procedure to cover structural integrity analysis to avoid failures due to fracture, fatigue, creep and corrosion. This new FFS Procedure has adopted the SINTAP approach for assessing of the welded structures. This paper describes the FITNET FFS weld assessment route and also aims to demonstrate suitability of weld joint assessment route of the FITNET FFS Procedure in prediction of the critical conditions of various advanced welded joints containing flaw. The welded specimens used in this work cover conventional multi-pass welded Inconel-718 turbine blade (T-joint), center cracked wide plates of electron beam welded 13% Cr supermartensitic stainless steel, laser beam welded shipbuilding C-Mn steel and aluminum alloy. The results are showing that the weld strength mismatch analysis option of the FITNET FFS is conservative and degree of conservatism is similar to the analysis options for the homogeneous materials. This provides confidence in the use of the FITNET FFS procedure for assessing of the structural significance of flaws in welded structures.

scholarly journals Conducting polymer materials

2003 ◽  
Vol 57 (11) ◽  
pp. 511-525 ◽  
Author(s):  
Slobodan Jovanovic ◽  
Gordana Nestorovic ◽  
Katarina Jeremic
Keyword(s):  
Molecular Structure ◽  
Conducting Polymers ◽  
Polymer Composites ◽  
Conducting Polymer ◽  
Future Development ◽  
Polymer Materials ◽  
Structure And Properties ◽  
Considerable Research ◽  
The Subject ◽  
Conducting Polymer Composites

Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a) conducting polymers the conductivity of which is the result of their molecular structure, and b) conducting polymer composites (EPC), is given in this paper. The applications and future development of this group of polymer materials is also discussed.

A Comparison of Fracture Assessment Methods in Several Structural Integrity Assessment Procedures

2009 ◽  
Author(s):  
Tiecheng Yang ◽  
Xuedong Chen ◽  
Zhichao Fan
Keyword(s):  
Structural Integrity ◽  
Limit Load ◽  
Assessment Method ◽  
Assessment Methods ◽  
Safety Factors ◽  
Specific Calculation ◽  
Integrity Assessment ◽  
Fracture Assessment ◽  
Partial Safety Factors ◽  
Assessment Procedures

For the fracture assessment method internationally used in different structural integrity assessment procedures, such as R6, BS 7910, FITNET API 579 and GB/T 19624, this paper gives the results of analytical comparisons in combination with specific calculation examples by comparing different assessment options or levels, the partial safety factors (PSFs), limit load solutions, stress intensity factor solutions, residual stress distribution and treatment methods, secondary stresses and ρ factor solutions etc., which provide a basis for improvement of fracture assessment methods.

Fracture Assessment of a Clad Steel Using the SINTAP Defect Assessment Procedure

2002 ◽  
Author(s):  
A. K. Motarjemi ◽  
M. Koc¸ak
Keyword(s):  
Structural Integrity ◽  
Complex Structure ◽  
Material Structure ◽  
Assessment Procedure ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Clad Layer ◽  
Failure Loads ◽  
Fracture Assessment ◽  
Clad Steel

In many critical industries such as nuclear, chemical and petrochemical industries, bi-material components in the form of clad plates are used due to their superior environmental and mechanical properties. During the service life of these bi-material components, cracks or crack-like defects may develop in the clad layer and penetrate into the substrate. The assessment of the integrity of such a cracked as well as complex structure would be an important task. Hence, this study is aimed at applying the recently developed European Structural Integrity Assessment Procedure (SINTAP) to a through thickness centre cracked clad steel wide plate to validate the procedure for this type of bi-material structure. Based on the available input data, various assessment levels as well as two different assessment routes, namely crack driving force (CDF) and failure assessment diagram (FAD), can be used for predicting the failure loads. In principle both routes should provide similar results and this has been verified by having very similar results for both SINTAP routes. Furthermore, the degree of conservatism has been reduced by using higher analysis levels of SINTAP.

Advances and Challenges in Structural Integrity

2007 ◽  
Vol 7-8 ◽  
pp. 13-22 ◽  
Author(s):  
Andrew H. Sherry
Keyword(s):  
Numerical Methods ◽  
Structural Integrity ◽  
Assessment Methods ◽  
Irradiation Effects ◽  
Reliable Prediction ◽  
Integrity Assessment ◽  
Microstructural Effects ◽  
Thermal Irradiation ◽  
Mechanistic Understanding

This paper provides an overview of four key challenges for structural integrity assessment methods: surface technology and incubation / initiation of defects, microstructural effects on weld performance, realistic loading and defect morphologies and thermal / irradiation effects on materials and structures. These challenges will be met by the application of emerging experimental and numerical methods which will facilitate the development of a mechanistic understanding of these four challenges alongside mechanistically-based models to enable the reliable prediction of component performance outside the available database of materials behaviour.

Structural Integrity for Nuclear Power Plant Against Excessive Load on Design Extension Condition

2013 ◽  
Author(s):  
Daigo Watanabe ◽  
Kiminobu Hojo
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Safety Factors ◽  
Design Code ◽  
Acceptance Criteria ◽  
Integrity Assessment ◽  
Current Design ◽  
Factor Design ◽  
Excessive Load ◽  
Load And Resistance Factor

This paper introduces an example of structural integrity evaluation for Light Water Reactor (LWR) against excessive loads on the Design Extension Condition (DEC). In order to assess the design acceptance level of DEC, three acceptance criteria which are the stress basis limit of the current design code, the strain basis limit of the current design code and the strain basis limit by using Load and Resistance Factor Design (LRFD) method were applied. As a result the allowable stress was increased by changing the acceptance criteria from the stress basis limit to the strain basis limit. It is shown that the practical margin of the LWR’s components still keeps even on DEC by introducing an appropriate criterion for integrity assessment and safety factors.

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