scholarly journals Long-Term Marine Environment Exposure Effect on Butt-Welded Shipbuilding Steel

2021 ◽  
Vol 9 (5) ◽  
pp. 491
Author(s):  
Goran Vukelic ◽  
Goran Vizentin ◽  
Josip Brnic ◽  
Marino Brcic ◽  
Florian Sedmak
Keyword(s):  
Marine Environment ◽  
Structural Integrity ◽  
Negative Impact ◽  
Extreme Environments ◽  
Steel Structures ◽  
Relative Mass ◽  
Mechanical Degradation ◽  
Shipbuilding Steel ◽  
Exposure Effect ◽  
Corrosion Pits

Extreme environments, such as marine environments, have negative impacts on welded steel structures, causing corrosion, reduced structural integrity and, consequently, failures. That is why it is necessary to perform an experimental research sea exposure effect on such structures and materials. Research presented in this paper deals with the mechanical behavior of butt-welded specimens made of AH36 shipbuilding steel when they are exposed to a natural marine environment (water, seawater, sea splash) for prolonged periods (3, 6, 12, 24, and 36 months). The usual approach to such research is to perform accelerated tests in a simulated laboratory environment. Here, relative mass change due to corrosion over time is given along with calculated corrosion rates. Corroded surfaces of specimens were inspected using optical and scanning electron microscopy and comparison, based on the numbers and dimensions of the corrosion pits (diameter and depth) in the observed area. As a result, it can be concluded that exposure between 3 and 6 months shows significant influence on mass loss of specimens. Further, sea splash generally has the most negative impact on corrosion rate due to the combined chemical and mechanical degradation of material. Pit density is the highest at the base metal area of the specimen. The diameters of the corrosion pits grow over the time of exposure as the pits coalesce and join. Pit depths are generally greatest in the heat affected zone area of the specimen.

Facing extremes: archaeal surface-layer (glyco)proteins

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3347-3351 ◽  
Author(s):  
Jerry Eichler
Keyword(s):  
Surface Layer ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Protein Biosynthesis ◽  
Extreme Environments ◽  
Archaeal Protein ◽  
The Face ◽  
Micro Organisms ◽  
Physical Challenges ◽  
Insight Into

Archaea are best known in their capacities as extremophiles, i.e. micro-organisms able to thrive in some of the most drastic environments on Earth. The protein-based surface layer that envelopes many archaeal strains must thus correctly assemble and maintain its structural integrity in the face of the physical challenges associated with, for instance, life in high salinity, at elevated temperatures or in acidic surroundings. Study of archaeal surface-layer (glyco)proteins has thus offered insight into the strategies employed by these proteins to survive direct contact with extreme environments, yet has also served to elucidate other aspects of archaeal protein biosynthesis, including glycosylation, lipid modification and protein export. In this mini-review, recent advances in the study of archaeal surface-layer (glyco)proteins are discussed.

scholarly journals Assessment of Anti-Corrosion Performances of Coating Systems for Corrosion Prevention of Offshore Wind Power Steel Structures

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 970 ◽  
Author(s):  
Sung-Hyun Eom ◽  
Seong-Soo Kim ◽  
Jeong-Bae Lee
Keyword(s):  
Wind Power ◽  
Adhesion Strength ◽  
Marine Environment ◽  
Power Plants ◽  
Salt Spray ◽  
Steel Structures ◽  
Offshore Wind ◽  
Coating System ◽  
Fracture Type ◽  
Offshore Wind Power

The anti-corrosion performance of coating systems (cathode protection, organic coating, and duplex coating) applied to prevent the corrosion of offshore wind power plants was assessed. As an assessment method, the adhesion strength of each coating system was evaluated after exposing the coatings to the marine environment and an indoor salt spray test. It was confirmed that the adhesion strength varied depending on the exposure period, and the deterioration of adhesion strength was related to the fracture type of each coating layer. In addition, the fracture type of each coating system was analyzed and the adhesion strength was corrected according to the fracture type. The corrosion rates after exposure to the marine environment and indoor salt spray were compared and examined using the corrected values.

Relocatable Tide Prediction and Storm Surge Forecasting

2018 ◽  
Author(s):  
Thomas Prime
Keyword(s):  
Sea Level ◽  
Storm Surge ◽  
Marine Environment ◽  
Agricultural Land ◽  
Extreme Event ◽  
Negative Impact ◽  
Early Warning Systems ◽  
Coastal Communities ◽  
Prevention Measures ◽  
Storm Surge Forecasting

The marine environment represents a large and important resource for communities around the world. However, the marine environment increasingly presents hazards that can have a large negative impact. One important marine hazard results from storms and their accompanying surges. This can lead to coastal flooding, particularly when surge and astronomical high tides align, with resultant impacts such as destruction of property, saline degradation of agricultural land and coastal erosion. Where tide and storm surge information are provided and accessed in a timely, accurate and understandable way, the data can provide: 1. Evidence for planning: Statistics of past conditions such as the probability of extreme event occurrence can be used to help plan improvements to coastal infrastructure that are able to withstand and mitigate the hazard from a given extreme event. 2. Early warning systems: Short term forecasts of storm surge allow provide early warnings to coastal communities enabling them to take actions to allow them to withstand extreme events, e.g. deploy flood prevention measures or mobilise emergency response measures. Data regarding sea level height can be provided from various in-situ observations such as tide gauges and remote observations such as satellite altimetry. However, to provide a forecast at high spatial and temporal resolution a dynamic ocean model is used. Over recent decades the National Oceanography Centre has been a world leading in developing coastal ocean models. This paper will present our progress on a current project to develop an information system for the Madagascan Met Office. The project, C-RISC, being executed in partnership with Sea Level Research Ltd, is translating the current modelling capability of NOC in storm surge forecasting and tidal prediction into a system that will provide information that can be easily transferred to other regions and is scalable to include other hazard types The outcome, an operational high-resolution storm surge warning system that is easy to relocate, will directly benefit coastal communities, giving them information they need to make effective decisions before and during extreme storm surge events.

Structural Integrity of Welded Steel Structures

1999 ◽  
Vol 167-168 ◽  
pp. 142-151 ◽  
Author(s):  
T.M. Roberts ◽  
A.W. Davies ◽  
Karen M. Holford
Keyword(s):  
Structural Integrity ◽  
Steel Structures ◽  
Welded Steel

Analysis on Critical CTOD of Long-Term Used Penstock

2017 ◽  
Vol 741 ◽  
pp. 57-62
Author(s):  
Fumito Kawamura ◽  
Masazumi Miura ◽  
Ryuichiro Ebara ◽  
Keiji Yanase
Keyword(s):  
Fracture Toughness ◽  
Structural Integrity ◽  
Steel Structures ◽  
Chemical Compositions ◽  
Structural Components ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Critical Crack ◽  
Crack Tip Opening

Many studies have been conducted to characterize the fracture toughness of structural steels and their welded joints. However, most studies focus on newly developed steels, and the number of studies on the fracture toughness of long-term used steels in structural components is rather limited. Furthermore, a lack of data on the fracture toughness causes difficulties in evaluating the structural integrity of existing steel structures. In this study, CTOD tests were performed to characterize the fracture toughness of penstock that has been in service for 50 years. By measuring the critical crack tip opening displacement in conjunction with analysis for chemical compositions, the characteristics of fracture toughness were investigated.

Proposal for Evaluation With Strain-Based Criterion of Impact Phenomena Between Steel Structure and Tornado Missile

2016 ◽  
Author(s):  
Yuko Sakamoto ◽  
Koji Shirai ◽  
Toshiko Udagawa ◽  
Shunsuke Kondo
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Impact Analysis ◽  
Structural Integrity ◽  
Steel Structures ◽  
Severe Accident ◽  
Numerical Code ◽  
Pressurized Water ◽  
Impact Phenomena ◽  
The Impact

In Japan, nuclear power plants must be protected from tornado missiles that are prescribed by Nuclear Regular Authority (NRA). When evaluating the structural integrity of steel structures in the plant with impact analysis by numerical code, strain-based criteria are appropriate because the tornado missiles have huge impact energy and may cause large deformation of the structures. As one of the strain-based criteria, the Japan Society of Mechanical Engineers (JSME) prescribes limiting triaxial strain for severe accident of Pressurized Water Reactor (PWR) steel containment. To confirm whether or not this criterion is appropriate to the evaluation of the impact phenomena between the steel structures and the tornado missiles, a free drop impact experiment to steel plates (carbon steel and austenitic stainless steel) was carried out with heavy weights imitated on one of the tornado missiles, followed by an impact analysis of the experiment with AUTODYN code and the JSME strain-based criterion. Consequently, it was confirmed that the strain-based criterion of JSME standard was for evaluating the fracture of steel structures caused by tornado missiles.

Study on Structural Integrity Analysis of Tubular Reactor With Corrosion Pits in LDPE Plant

2013 ◽  
Author(s):  
Jianping Zhao ◽  
Chunsheng Miao ◽  
Jiang Chen ◽  
Xinchun Guan
Keyword(s):  
Bearing Capacity ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Tubular Reactor ◽  
Operating Conditions ◽  
Ultrahigh Pressure ◽  
Operating Pressure ◽  
Mechanism Analysis ◽  
Tubular Reactors ◽  
Corrosion Pits

Ultrahigh pressure polyethylene tubular reactors were widely used in Petrochemical Industry. Because of corrosion, fatigue crack and other defects easily caused by a high operating pressure and complicated operating conditions for tubular reactor, their safety was a concerned issue in the engineering field. This paper conducted genetic mechanism analysis on ultrahigh pressure polyethylene tubular reactors with corrosion pits in LDPE plant. The ultimate bearing capacity analysis was carried out for tubular reactor with pits by three-dimensional finite element method. The effects of depth, length and width of pits on structural bearing capacity were discussed. The results indicated that the critical pit depth of tubular reactor was 8mm.

The Potential for Non-Conservative Results From the Probabilistic Fracture Mechanics Analyses Is Assessed Based on the Collected Observation of Fatigue Cracks in Offshore Steel Structures

2017 ◽  
Author(s):  
Ole Tom Vårdal
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Structural Integrity ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Lessons Learned ◽  
Probabilistic Methods ◽  
Growth Potential

In structural integrity management, it is essential to know the fatigue crack growth potential. The lessons learned from use of refined fatigue analyses, fracture mechanics and probabilistic methods for platforms in-service are presented. For ageing offshore units of semi-submersible design, the inspection history of more than 20 000 NDT inspections and detection of close to 1000 fatigue cracks, are used in this study. These experience data are used to assess the potential for Non-conservative estimate for the fatigue crack growth potential.

scholarly journals AN EVALUATION OF THE PHYSICAL IMPACT AND STRUCTURAL INTEGRITY OF A GEOTEXTILE SURF REEF

2012 ◽  
Vol 1 (33) ◽  
pp. 21 ◽  
Author(s):  
Emma Jane Rendle ◽  
Mark Davidson
Keyword(s):  
Wave Field ◽  
Marine Environment ◽  
Structural Integrity ◽  
Wave Climate ◽  
South Coast ◽  
Coastal Protection ◽  
Shallow Marine ◽  
Physical Impact ◽  
The Impact

Geotextile artificial surfing reefs (ASR) are being considered by coastal planners due to their multifunctional potential for coastal protection and habitat provision, as well as additional recreational amenity. However, little research exists on the impact of submerged geotextile structures on the physical marine environment. Europe’s first ASR was constructed in 2009 on the south coast of England in Boscombe and is the case study for this paper. This research investigates the claims regarding the structural resilience of an ASR, the modifications to the inshore wave climate and the shoreline response induced by the introduction of an ASR to a system. The Boscombe ASR has suffered from damage, two major geotextile sand filled containers have degraded in this shallow marine environment in two years post-construction. Observations and simulations presented indicate ameliorated wave field leeward of the ASR. There is little shoreline response, given the structures distance offshore, and no salient or widening of the beach has occurred.

scholarly journals Japanese knotweed (Fallopia japonica): An analysis of capacity to cause structural damage (compared to other plants) and typical rhizome extension

2018 ◽  
Author(s):  
Mark Fennell ◽  
Max Wade ◽  
Karen L Bacon
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Negative Impact ◽  
Significant Risk ◽  
Japanese Knotweed ◽  
Socioeconomic Impacts ◽  
Fallopia Japonica ◽  
The United Kingdom ◽  
Invasive Species Control ◽  
The Uk

Fallopia japonica (Japanese knotweed) is a well-known invasive alien species in the United Kingdom and elsewhere in Europe and North America. The plant is known to have a negative impact on local biodiversity, flood risk, and ecosystem services; but in the UK it is also considered to pose a significant risk to the structural integrity of buildings that are within 7 m of the above ground portions of the plant. This has led to the presence of the plant regularly being used to refuse mortgage applications. Despite the significant socioeconomic impacts of such automatic mortgage option restriction, little research has been conducted to investigate this issue. The ‘7 m rule’ is derived from widely adopted government guidance in the UK. This study considered if there is evidence to support this phenomenon in the literature, reports the findings of a survey of invasive species control contractors and property surveyors to determine if field observations support these assertions, and reports a case study of 68 properties, located on three streets in northern England where F. japonicawas recorded. Additionally, given the importance of proximity, the 7 m rule is also tested based on data collected during the excavation based removal of F. japonicafrom 81 sites. No support was found to suggest that F. japonicacauses significant damage to built structures, even when it is growing in close proximity to them and certainly no more damage than other plant species that are not subject to such stringent lending policies. It was found that the 7 m rule is not a statistically robust tool for estimating likely rhizome extension. F. japonica rhizome rarely extends more than 4 m from above ground plants and is typically found within 2 m for small stands and 2.5 m for large stands. Based on these findings, the practice of automatically restricting mortgage options for home buyers when F. japonicais present, is not commensurate with the risk.

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