Fitness for Service Analysis of Structures Using the FITNET Procedure: An Overview

2005 ◽  
Author(s):  
Mustafa Koc¸ak
Keyword(s):  
Nuclear Power ◽  
Failure Modes ◽  
Structural Integrity ◽  
Cost Savings ◽  
Industrial Sector ◽  
Structural Instability ◽  
General Purpose ◽  
Engineering Structures ◽  
Industrial Sectors ◽  
Size Limits

A number of Fitness-for-Service (FFS) procedures (include analytical methods) have been specifically developed and used to address the components of a particular industrial sector. A number of industrial sectors, such as nuclear power, petrochemical, offshore, aerospace or pipeline girth weld applications have established FFS standards in place for the assessment of flaws found in-service. Some methods for design and remaining life assessments of fatigue-loaded structures are still unduly conservative in different loading regimes. Hence, there is still a need to generate a general purpose, unified, comprehensive and updated FFS methodology in Europe by covering four major failure modes (fracture, fatigue, creep and corrosion) in metallic load bearing components with or without welds. As a result, the European Community funded the project FITNET in the form of a Thematic Network (TN) organisation 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. FITNET TN is a four year project with the objective of developing and extending the use of FITNET FFS Procedure for welded and non-welded metallic structures throughout Europe. It is partly funded by the European Commission within the fifth framework programme and launched at February 2002. The network currently consists of 50 organisations from 16 European and three non-European countries representing various industrial sectors and academia. Further information can be found in the FITNET TN website: http://www.eurofitnet.org. FITNET Fitness-for-Service analysis of engineering structures aims to provide better design principles, support for fabrication of new components, prevention of service failures due to fracture, fatigue, creep and corrosion damages (no coverage of structural instability due to buckling). FITNET FFS criteria can be used to establish the size limits for defects in various engineering structures and can provide substantial cost savings in operating such structures. The use of the FITNET FFS Procedure involves making an assessment of a component containing a defect to ensure its structural integrity for its intended design life or until its next inspection period. The outcome of the assessment of a component in service is a decision to operate as is, repair, monitor (including re-setting of inspection intervals), or replace. The aim of this paper is to give an overview of the objectives and technical content of the FITNET FFS Procedure currently developed and validated by the European Fitness for Service Network FITNET and hence inform the offshore technical community.

scholarly journals Titanium in Shipbuilding and Other Technical Applications

2020 ◽  
Vol 321 ◽  
pp. 02001
Author(s):  
A.S. Oryshchenko ◽  
V.P. Leonov ◽  
V.I. Mikhailov ◽  
P.A. Kuznetsov ◽  
A.V. Alexandrov
Keyword(s):  
Titanium Alloys ◽  
Nuclear Power ◽  
Power Plants ◽  
Oil And Gas ◽  
Aerospace Industry ◽  
Industrial Sector ◽  
New Production ◽  
Chemical Pulp ◽  
Industrial Sectors ◽  
Major Development

Aerospace industry is currently the major consumer of titanium in Russia. Shipbuilding is its second largest consumer. Oil and gas, chemical, pulp-and-paper and other industries use less titanium. In the Russian industrial sector titanium is geting more applicable. Since the 13th World Ti-2015 Conference the titanium application trends have persisted [1]. Among the major development trends of titanium alloys one should note the development of titanium alloys for deep-water marine facilities, case designs of small-size nuclear power plants, the development of additive technologies, the technologies of isostatic pressing, the development of titanium products by new production facilities, etc. Titanium is still considered an advanced structural material used for scientific and technical progress in different industrial sectors.

scholarly journals Delamination buckling of a laminated composite shell panel using cohesive zone modelling

2021 ◽  
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Composite Shell ◽  
Laminated Composite ◽  
Composite Panel ◽  
Complex Nature ◽  
Interface Failure ◽  
Engineering Structures ◽  
Fiber Failure ◽  
Delamination Buckling

Abstract Laminated composite shell panels take part in several engineering structures. Due to their complex nature, failure modes in composites are highly dependent on the geometry, direction of loading and orientation of the fibers. However, the design of composite parts is still a delicate task because of these fiber failure modes, which includes matrix failure modes or other so-called interlaminar interface failure such as delamination, that corresponds to the separation of adjacent layers of the laminate as a consequence of the weakening of interface layer between them. In this work, impact-induced delamination represented as a circular single delamination is investigated, as it can reduce greatly the structural integrity without getting detected. Furthermore, attention is focused on its effect upon the post-buckling response and the compressive strength of a composite panel. The delamination buckling was modelled using the cohesive element technique under Abaqus software, in order to predict delamination growth and damage propagation while observing their effects on the critical buckling load.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 5 — Fatigue Test of the Crossover Piping

2014 ◽  
Author(s):  
Kotoyo Mizuno ◽  
Hiroshi Shimizu ◽  
Masakazu Jimbo ◽  
Naohiko Oritani ◽  
Shigenobu Onishi
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Failure Modes ◽  
Structural Integrity ◽  
Relative Displacement ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper provides a part of the series of “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. It is assumed the main steam crossover piping is damaged by the ratcheting deformation based on the relative displacement and the inertia load by the earthquake between the buildings and the internal pressure. This part shows a low cycle ratcheting fatigue test using the scaling model under the combined loadings based on the relative displacement and the inertia load by the earthquake between the buildings and analyses were performed to confirm the failure modes and the fatigue life of the pipe elbow for the fatigue damage of the long-period ground motion. As a result, the fatigue life under combined loads was sufficiently higher than the design criteria and analyses are good match with the test results. So, it confirmed the structural integrity of the crossover piping.

Dynamic Response of a Nuclear Power Plant Subjected to External Accident Event

2010 ◽  
Author(s):  
Rosa Lo Frano ◽  
Giuseppe Forasassi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Nuclear Reactor ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Containment System ◽  
Dynamic Loadings ◽  
Water Reactors ◽  
Set Up

In recent times there is a renewed worldwide interest in the development and application of advanced nuclear power plants (NPPs). Decisions on the construction of several NPPs with evolutionary light water reactors have been made (e.g. EPR in Finland and France, AP1000 in China, etc.) and more are under consideration for licensing in several countries. Innovative NPPs are designed to be built with very broad siting conditions; therefore the safety aspects related to the external events might follow new scenarios and failure modes, different from those well known for the currently operated reactors. In this paper, the intent is evaluating the structural integrity of a nuclear containment system subjected to dynamic loadings due to a Design Base Earthquake and an aircraft impact (large size civilian jets or military aircrafts impact), which represent the two most relevant external accidents that should be considered and investigated as part of the basic design of a NPP in particular a III+ and IV Gens. In fact a suitable safety design of the NPP containment system (according to the international safety and design code guidelines, as NRC or IAEA ones), even if designed to meet other design goal, may represent a “built-in protection” to avoid or mitigate the effects of mentioned dynamic loadings. To the purpose a rather sophisticated numerical methodology, adopting finite element (FEM) approach, is employed for studying the overall dynamic behaviour of nuclear reactor and to determine the structural effects of the propagation of dynamic seismic as well as impulsive loads (containment structure response) up to the relevant nuclear components. Therefore representative three-dimensional FEM models of mentioned NPP containment and aircraft structures were set up, and used, in the performed analyses taking also into account the suitable materials behaviour and their related constitutive laws as well as the seismic excitation (determined according to the NRC rules). Moreover the performed analyses and the carried out response analyses of internal components, to both the ground motion and impact loads, were studied to check the considered NPP containment strength reserve in the case of the considered events. The obtained results seem to confirm the possibility to achieve an optimization of the NPP internal components.

CHP for Buildings: The Challenge of Delivering Value to the Commercial Sector

2002 ◽  
Author(s):  
M. Cowie ◽  
A. Marantan ◽  
P. W. Garland ◽  
R. Rademacher
Keyword(s):  
Waste Heat ◽  
Geographic Location ◽  
Cost Savings ◽  
Industrial Sector ◽  
Hot Water ◽  
Commercial Sector ◽  
Commercial Building ◽  
Peak Shaving ◽  
Industrial Sectors ◽  
Environmental Savings

The commercial sector has historically not seen the same level of investment in Combined Cooling, Heating and Power (CHP) as the industrial sector. The average commercial building has smaller and more diverse energy requirements than would be expected at a typical industrial site. Consequently, even though the electrical requirements of the commercial and industrial sectors are very similar there is nine times more installed industrial CHP capacity than commercial CHP in the U.S. However, the advent of microturbines and increasing commercial viability of fuel cells promises generator sizes much more suitable for use in the commercial sector. There are many possible uses for the waste heat in a commercial building, depending upon geographic location, occupant requirements and the energy cost structures of both fuel and grid electricity. Possible waste heat technologies include absorption chillers, humidifiers, desiccant dehumidifiers, steam generators, hot water heating, space heating and thermal storage. Several of these could be combined with a generator to produce a commercial CHP for Buildings package. A well-designed and operated package should deliver energy and environmental savings as well as significant cost savings to the customer. Other potential value streams are improved indoor air quality, peak shaving to reduce demand charges, enhanced power reliability, tradable environmental credits or grid independence. This presentation is a broad discussion of the challenges that CHP faces when competing in the commercial sector and the technologies and strategies that will help overcome them.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

The technological transformation of Russia's industrial sectors: Difficulties and prospects

2020 ◽  
Vol 16 (9) ◽  
pp. 1674-1697
Author(s):  
O.P. Smirnova ◽  
A.O. Ponomareva
Keyword(s):  
Production Method ◽  
Industrial Sector ◽  
The State ◽  
Industrial Complex ◽  
Economic Activities ◽  
Resource Saving ◽  
Technological Transformation ◽  
Modern Approach ◽  
Industrial Enterprises ◽  
Industrial Sectors

Subject. The article focuses on contemporary trends in the industrial and socio-economic development of Russia during the technological transformation of its sectors. Objectives. The study is an attempt to analyze what opportunities and difficulties may arise for the development of the industrial sectors in Russia. We also examine the dynamics of key development indicators of the industrial sectors, point out inhibitors of their competitiveness. Methods. The methodological framework comprises general methods of systems, structural-functional and comprehensive approaches to analyzing economic phenomena. We applied graphic, economic-statistical methods of research, conventional methods of grouping, comparison and generalization, and the logic, systems and statistical analysis. Results. We display how industrial sectors develop over time by type of economic activities. The article provides the rationale for structural rearrangements and further innovation-driven development of the industries. We display that the Russian industries technologically depend om imported production technologies. We substantiate the renewal of assets and technologies at industrial enterprises, and retain and develop human capital. Conclusions and Relevance. Primarily, the Russian economy should be digitalized as a source of the long-term economic growth. Notably, industrial enterprises should replace their linear production method with that of the circular economy and implement resource-saving innovative technologies. The State evidently acts as the leading driver of technological retrofitting of the industrial sector. If the State holds the reasonable and appropriate industrial policy at the federal and regional levels and configure its tools to ensure the modern approach to developing the industries in a competitive fashion, the industrial complex will successfully transform into the innovative economy.

Effect of Creep on the Residual Stresses in Tube-to-Tubesheet Joints

2010 ◽  
Author(s):  
Nor Eddine Laghzale ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Contact Pressure ◽  
Analytical Model ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Environmental Safety ◽  
Maintenance Cost ◽  
Joint Interface ◽  
Plant Safety ◽  
Material Creep ◽  
Nuclear Power Plant Safety

Steam generators are the subject of major concern in nuclear power plant safety. Within these generators, in addition to the structural integrity, the gross tightness barrier, which separates the primary and secondary circuits, is primarily ensured by the presence of a residual contact pressure at the tube-to-tubesheet joint interface. Any leakage is unacceptable, and its consequences are very heavy in terms of the human and environmental safety as well as maintenance cost. Some studies have been conducted to understand the main reasons for such a failure. However, no analytical model able to predict the attenuation of the residual contact pressure under the effect of material creep relaxation behavior. The development of a simple analytical model able to predict the change of the residual contact pressure as a function of time is laid out in this paper. The results from the analytical model are checked and compared with those of finite elements.

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.

scholarly journals Physical modelling of failure in composites

2016 ◽  
Vol 374 (2071) ◽  
pp. 20150280 ◽  
Author(s):  
Ramesh Talreja
Keyword(s):  
Composite Materials ◽  
Failure Modes ◽  
Structural Integrity ◽  
Failure Mechanisms ◽  
Local Stress ◽  
Physical Modelling ◽  
Stress Fields ◽  
Systematic Analysis ◽  
Composite Failure ◽  
Failure Theories

Structural integrity of composite materials is governed by failure mechanisms that initiate at the scale of the microstructure. The local stress fields evolve with the progression of the failure mechanisms. Within the full span from initiation to criticality of the failure mechanisms, the governing length scales in a fibre-reinforced composite change from the fibre size to the characteristic fibre-architecture sizes, and eventually to a structural size, depending on the composite configuration and structural geometry as well as the imposed loading environment. Thus, a physical modelling of failure in composites must necessarily be of multi-scale nature, although not always with the same hierarchy for each failure mode. With this background, the paper examines the currently available main composite failure theories to assess their ability to capture the essential features of failure. A case is made for an alternative in the form of physical modelling and its skeleton is constructed based on physical observations and systematic analysis of the basic failure modes and associated stress fields and energy balances. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

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