Corrosion-Fatigue Structural Integrity Assessment Using a Thermodynamic Entropy Based Damage Approach

2015 ◽  
Author(s):  
Anahita Imanian ◽  
Mohammad Modarres
Keyword(s):  
Entropy Generation ◽  
Corrosion Fatigue ◽  
Structural Integrity ◽  
Degradation Mechanism ◽  
Health Assessment ◽  
Irreversible Thermodynamics ◽  
Integrity Assessment ◽  
Thermodynamic Entropy ◽  
Equilibrium Processes ◽  
Thermodynamic Forces

Using fundamentals of irreversible thermodynamics, with specific focus on entropy generation, this paper studies the structural integrity of degraded materials. All damage mechanisms share a common feature namely energy dissipation. Dissipation, as a fundamental measure for irreversibility in a thermodynamic treatment of non-equilibrium processes, is quantified by entropy generation. Based on the theoretical relationship between entropy generation and generalized thermodynamic forces and fluxes, the entropic damage is measured during a corrosion-fatigue degradation experiment. Life estimation of components, which were subject to complex corrosion-fatigue degradation mechanism, was then estimated through a proposed entropic-based prognostic framework. The performance of predictions was evaluated and compared with previous predictions in terms of the influence of additional features on components health assessment.

Structural Integrity Assessment for Various Failure Modes Using a Risk-Based Maintenance Method

2004 ◽  
Author(s):  
Hiroyuki Horikawa ◽  
Masaki Yoshikawa ◽  
Nobuo Takasu
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Ground Deformation ◽  
Degradation Mechanism ◽  
Risk Level ◽  
Integrity Assessment ◽  
Evaluation Approach ◽  
Actual Damage ◽  
Maintenance Plan ◽  
Good Agreement

In this paper, a newly developed system called RBM (Risk-Based Maintenance) is presented. The system is used to describe the structural integrity of buried pipeline based on the index of risk that is defined in the product of the failure frequency and the consequence. Various failure modes corresponding to each degradation mechanism are included, and the estimation of failure probability that the external load exceeds the structure resistance is carried out. As the result of trial evaluation compared with the past earthquake incident, it is in good agreement with actual damage of pipeline subjected to liquefaction and large ground deformation. Furthermore, the system enables operators to maintain the structural integrity for service life by providing the most optimized maintenance plan according to the risk level. The features of the quantitative risk evaluation approach and the benefits of the developed RBM system as a means of structural integrity assessment are also discussed.

On the thermodynamics of degradation

2008 ◽  
Vol 464 (2096) ◽  
pp. 2001-2014 ◽  
Author(s):  
M.D Bryant ◽  
M.M Khonsari ◽  
F.F Ling
Keyword(s):  
Entropy Generation ◽  
Fretting Wear ◽  
Material Degradation ◽  
Thermodynamic Entropy ◽  
Machine Reliability ◽  
Science Base ◽  
Degradation Models ◽  
Accelerated Failure ◽  
Thermodynamic Forces

The science base that underlies modelling and analysis of machine reliability has remained substantially unchanged for decades. Therefore, it is not surprising that a significant gap exists between available machinery technology and science to capture degradation dynamics for prediction of failure. Further, there is a lack of a systematic technique for the development of accelerated failure testing of machinery components. This article develops a thermodynamic characterization of degradation dynamics, which employs entropy, a measure of thermodynamic disorder, as the fundamental measure of degradation; this relates entropy generation to irreversible degradation and shows that components of material degradation can be related to the production of corresponding thermodynamic entropy by the irreversible dissipative processes that characterize the degradation. A theorem that relates entropy generation to irreversible degradation, via generalized thermodynamic forces and degradation forces, is constructed. This theorem provides the basis of a structured method for formulating degradation models consistent with the laws of thermodynamics. Applications of the theorem to problems involving sliding wear and fretting wear, caused by effects of friction and associated with tribological components, are presented.

scholarly journals Strain Monitoring Strategy of Deformed Membrane Cover Using Unmanned Aerial Vehicle-Assisted 3D Photogrammetry

2020 ◽  
Vol 12 (17) ◽  
pp. 2738
Author(s):  
Benjamin Steven Vien ◽  
Leslie Wong ◽  
Thomas Kuen ◽  
Frank Courtney ◽  
Jayantha Kodikara ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Structural Integrity ◽  
Health Assessment ◽  
Treatment Plant ◽  
Real Life ◽  
Aerial Images ◽  
Critical Function ◽  
Integrity Assessment ◽  
Aerial Photogrammetry ◽  
Aerial Vehicle

Large structures and high-value assets require inspection and integrity assessment methodologies that ensure maximum availability and operational capabilities. Large membranes are used as floating covers at the anaerobic wastewater lagoons of Melbourne Water’s Western Treatment Plant (WTP). A critical function of this high-value asset pertains to the harnessing of the biogas gas generated at these lagoons as well as protecting the environment from the release of odours and greenhouse gases. Therefore, a proactive inspection and efficient management strategy are required to ensure these expensive covers’ integrity and continued operation. Not only is identifying the state of stress on the floating cover crucial for its structural integrity assessment, but the development of rapid and non-contact inspections will significantly assist in determining the “real-life” performance of the cover for superior maintenance management. This study investigates a strain determination method for WTP floating cover which integrates unmanned aerial vehicle (UAV)-assisted photogrammetry with finite element analyses to determine the structural integrity of these covers. Collective aerial images were compiled to form 3D digital models of the deformed cover specimens, which were then employed in computational and statistical analyses to assess and predict the strain of the cover. The findings complement the future implementation of UAV-assisted aerial photogrammetry for structural health assessment of the large floating covers.

Structural Assessment of Large Membrane Structures Using an Unmanned Aerial Vehicle Aided Photogrammetry: Determination of Flight Parameters and Trials at the Western Treatment Plant

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Leslie Wong ◽  
Frank Courtney ◽  
Benjamin Steven Vien ◽  
Thomas Kuen ◽  
Peter Douglas ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Structural Integrity ◽  
Surface Deformation ◽  
Health Assessment ◽  
Treatment Plant ◽  
Integrity Assessment ◽  
Structural Health ◽  
Structural Health Assessment ◽  
Aerial Vehicle ◽  
Flight Parameters

Abstract Floating covers are examples of a large membrane structure used at sewage treatment plants. At the Western Treatment Plant (WTP), Werribee, Melbourne, Australia, floating covers are used in the anaerobic lagoons. They are deployed to assist with the anaerobic treatment of the raw sewage beneath, to harness the methane-rich biogas generated, and for odor control. In this respect, these floating covers are important assets for harnessing a sustainable and renewable energy source, as well as protecting the environment from the release of the damaging greenhouse methane-rich biogas from the treatment plant. Given the continuous nature of the biological process beneath the cover, the forces imposed on the floating cover will change with time. Hence, the monitoring and the assessment of the structural integrity of the floating cover are of paramount importance. These floating covers are made from high-density polyethylene (HDPE), a polymeric material. The size of these covers, the hazardous environment, and the expected life span demand a novel, remotely piloted, unmanned aerial vehicle based noncontact technique for the structural health assessment. This assessment methodology will utilize photogrammetry as the basis for determining the surface deformation of the membrane. This paper reports on an experimental study to determine the flight parameters and to assess the accuracy of the measurement technique. It was conducted over an area having similar dimensions to the large covers at the WTP. There are also features in this area, which are of similar scale to those expected in the floating cover. A total of nine test flights were used to investigate the parameters for optimal definition of the significant features to describe the deformation of the floating cover. The findings inform the selection of the unmanned aerial vehicle assisted photogrammetry parameters for optimal flight altitude, photogrammetry image overlap, and flight grid path for future integrity assessment of the floating covers. Two trial flights at WTP are also discussed to demonstrate the effectiveness of this noncontact technique for the future structural health assessment and in assisting with the operation of this large high-value asset.

scholarly journals Remote Monitoring of Floating Covers Using UAV Photogrammetry

2020 ◽  
Vol 12 (7) ◽  
pp. 1118 ◽  
Author(s):  
Leslie Wong ◽  
Benjamin Steven Vien ◽  
Yue Ma ◽  
Thomas Kuen ◽  
Frank Courtney ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Wastewater Treatment Plants ◽  
Health Assessment ◽  
Treatment Plant ◽  
Renewable Resource ◽  
The State ◽  
Integrity Assessment ◽  
Structural Health Assessment ◽  
Aerial Vehicle ◽  
Definition Of

High-density polyethylene (HDPE) is commonly the material of choice for covered anaerobic lagoons (CAL) at wastewater treatment plants. The membrane floats on the wastewater, and hence is called a “floating cover”, and is used for odour control and to harvest the methane-rich biogas as a renewable resource to generate electricity. The floating cover is an expensive and high-value asset that demands an efficient methodology for the determination of a set of engineering quantities for structural integrity assessment. Given the dynamics of the anaerobic activities under the floating cover, the state of deformation of the floating cover is an engineering measurand that is useful for its structural health assessment. A non-contact measurement strategy is preferred as it offers practical and safety-related benefits over other methods. In collaboration with Melbourne Water Corporation (MWC), an unmanned aerial vehicle (UAV) assisted photogrammetry approach was developed to address this need. Following the definition of the appropriate flight parameters required to quantify the state of deformation of the cover, a series of periodic flights were operated over the very large floating covers at MWC’s Western Treatment Plant (WTP) at Werribee, Victoria, Australia. This paper aims to demonstrate the effectiveness and practicality of this inspection technique to determine the state of deformation of the floating covers measured over a ten-month period.

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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