Common Case Studies of Marine Structural Failures

Marine structures are designed with a requirement to have reasonably long and safe operational life with a risk of catastrophic failures reduced to the minimum. Still, in a constant wish for reduced weight structures that can withstand increased loads, failures occur due to one or several following causes: excessive force and/or temperature induced elastic deformation, yielding, fatigue, corrosion, creep, etc. Therefore, it is important to identify threats affecting the integrity of marine structures. In order to understand the causes of failures, structure’s load response, failure process, possible consequences and methods to cope with and prevent failures, probably the most suitable way would be reviewing case studies of common failures. Roughly, marine structural failures can be divided into structural failures of ships, propulsion system failures, offshore structural failure, and marine equipment failures. This book chapter will provide an overview of such failures taking into account failure mechanisms, tools used for failure analysis and critical review of possible improvements in failure analysis techniques

Prolonged Real Marine Environment Exposure of Composite Marine Structures

As fiber reinforced polymer (FRP) composites become ever more established construction materials in the marine industry sector the influence of the harsh environmental operational conditions and its consequence on failure prediction of such structures is an imperative. Coupons of epoxy/glass and polyester/glass with various fiber layout configurations have been submerged under the sea for prolonged periods (6 and 12 months) in order to assess the impact on mechanical behavior of the material exposed to real marine environment as opposed to the more commonly adopted artificially produced laboratory sea environment and accelerated testing. Changes in mass, marine microbiology growth, tensile strength and morphological structures were analyzed after submersion and compared with samples exposed to room environment. All coupons have shown mass increase due to seawater absorption and microorganism growth in the organic resins matrices. The dynamic and level of change in tensile strength proved to be dependent on the fiber layout configuration. Optical and scanning electron microscopical investigation performed showed significant matrix morphological changes primarily due to salt crystal formation and the impact of sea microorganisms embedding in the resin. The collected experimental data will be used to develop a more realistic environmental input parameters for structural modeling of marine structures

Common failures of ship propulsion shafts

This article aims to provide a critical review of the most common failures of ship propulsion systems as a crucial ship system, with emphasis on fatigue failure. The accent is given on the shaft of marine propulsion systems as a most common point of failures in the entire propulsion system. A general description of failure causes and failure analysis methodology is presented. Several representative case studies summaries for fatigue failure on critical points of the propulsion shaft are described. Torsional vibrations and geometric stress concentrations of the shaft are identified as the most common cause of fatigue failure. The importance of constant monitoring, measurement and data collection of fatigue indicators and indicative events that have influence on fatigue development is emphasized. Methods used in failure analysis are discussed and propositions for improvement are given, especially in terms of using numerical routines in failure prediction

Prospects for use of extended reality technology for ship passenger evacuation simulation

Safety of passengers on ships is usually investigated based on data available from post-accident reports, experimental research and/or numerical modelling of emergencies. As for the numerical modelling, ship passenger evacuation falls within a greater set of pedestrian evacuation research in which extended reality (XR) technology is playing important role lately. However, XR still strives to find its place in the modelling of ship passenger evacuation. This paper brings review of literature published on the topic of XR in pedestrian evacuation with special focus on the use of these technologies (e.g. virtual reality, augmented reality) in shipping industry. Findings are put in the context of IMO’s guidelines for evacuation analysis and prospect for use of XR for ship passenger evacuation simulation are presented

J-integral as possible criterion in material fracture toughness assessment

Numerical fracture toughness assessment of two types of steel, AISI 420 and AISI 431, has been conducted in this paper. The J-integral is chosen as a criterion for fracture behaviour comparison of compact type (CT) specimens made of investigated materials. The values of J-integral are determined through a newly developed algorithm using finite element (FE) stress analysis results of numerically simulated single specimen test method, which is usually employed for experimental J-integral assessment. J-integral values are presented in dependence on specimen crack growth size (Δa) for three initial measures of specimen\u27s crack size, a/W = 0.25, 0.5, 0.75

Dekonstruisanje liberalne izgradnje mira: lekcije sa Zapadnog Balkana

The paper contributes to the deconstruction of the liberal peacebuilding concept, particularly its main components of failed state and statebuilding, through the analysis of two internationally-backed statehood projects in the Western Balkans: Bosnia and Herzegovina and Kosovo. The authors analyse critical peacebuilding literature on these two cases to provide arguments for abandoning the failed state and state-building ideas as overly biassed and ideologically based. Instead, they suggest reintroducing the conceptualisation of state-making as a more suitable framework for understanding the post-war context and dynamics in the Western Balkans. Based on that premise, the authors conclude that the cases of Bosnia and Herzegovina and Kosovo should be approached from a broader historical and geographical perspective and call for the decentralisation of the "Westphalian state" and the reinstatement of the longue durée perspective in state-formation research, as well as the depathologisation of the subjects of that research.Tekst predstavlja doprinos dekonstrukciji koncepta liberalne izgradnje mira, posebno njegovih glavnih činilaca: neuspele države i izgradnje države, kroz analizu dva međunarodno podržana državna projekta na Zapadnom Balkanu: Bosne i Hercegovine i Kosova. Autori analiziraju kritičku literaturu o izgradnji mira posvećenu ovim dvama slučajevima kako bi ponudili argumente za napuštanje koncepata neuspele države i izgradnje države, zbog njihove preterane pristrasnosti i ideološke zasnovanosti. Umesto toga, oni predlažu vraćanje konceptu stvaranja države kao primerenijem teorijskom okviru za razumevanje posleratnog konteksta i dinamike na Zapadnom Balkanu. Polazeći od te pretpostavke, autori zaključuju da bi slučajevima Bosne i Hercegovine i Kosova trebalo pristupati iz šire istorijske i geografske perspektive i pozivaju na decentralizaciju ideje “vestfalske države”, vraćanje longue durée perspektivi u istraživanju stvaranja država, kao i na depatologizaciju predmeta tog istraživanja

ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels

Cultural violence as a longue duree process: from colonialism to humanitarianism

The main hypothesis of the paper is that Orientalism, as a form of cultural violence, represents a long-term historical structure which is reproduced through discourses and practices of various social systems. The authors apply genealogy and longue duree approaches to analyze discourses of colonialism, antisemitism, nationalism, and humanitarianism, indicating the long-lasting identity division along the West-East (Orient) axis, as well as continuity of the cultural content that implies the superiority of the Self and the inferiority of the Other. The analysis also shows that all these discourses, although mutually different, can be rooted in the Orientalist matrix and thus become instruments for legitimizing and justifying various forms of indirect (repression, exploitation) and direct violence (wars, genocide, ethnic cleansing). The paper aims to understand the different forms of violence and their complexity as precondition for violence prevention

Analysis of corrosion depth percentage on the inner bottom plates of aging bulk carriers with an aim to optimize corrosion margin

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels

Depression in the Light of Some Psychoanalytic Theories

Cilj je ovoga selektivnog preglednog članka sažeti neke od najpoznatijih psihoanalitičkih teorija o depresiji. Od Freudovog Tugovanja i melankolije 1917. psihoanaliza je ostvarila značajne iskorake u tumačenju depresije. Depresija je tumačena kao očajnički krik za ljubavlju, autoagresija, konflikt ega, fiksacija na iskustva bespomoćnosti, ekspresija neurotične strukture ličnosti i patološki ishod depresivne pozicije. Depresija je često povezana s agresijom, anksioznošću, krivnjom i narcizmom. U klasičnom psihoanalitičkom pristupu depresiji oralnost igra značajnu ulogu. S razvojem psihoanalitičkih teorija pojavili su se neki važni pojmovi: kognitivna trijada kao važna varijabla u depresiji koja uključuje negativnu percepciju sebe, svijeta i budućnosti, „sociotropne“ (društveno ovisne) i „autonomne“ vrste depresije, dominantni drugi i uloga terapeuta koji može postati dominantni ili značajni treći. Psihoanalitičke teorije s kraja 20. stoljeća dijele depresiju na anaklitnu i introjektivnu. U 21. stoljeću autori su opisali neurohormonsku, neurokemijsku i neuroimunološku pozadinu depresije potvrđujući na određen način neke od klasičnih psihoanalitičkih teorija.The aim of this selective review article is to summarize some of the best-known psychoanalytic theories regarding depression. Since Freud’s Mourning and Melancholia in 1917, psychoanalysis has made considerable steps forward in the interpretation of depression. Depression was seen as a despairing cry for love, aggression towards the self, a conflict of the ego, a fixation on experiences of helplessness and powerlessness, an expression of the neurotic personality structure, and depressive position. Depression is often linked with aggression, anxiety, guilt, and narcissism. In the classic psychoanalytic view of depression, orality plays a significant role. As psychoanalytic theories evolved, some important concepts emerged: the cognitive triad, which includes negative perceptions of the self, world, and future as an important variable in depression, “sociotropic” (socially dependent) and “autonomous” types of depression, the dominant other, and the role of the therapist who can become the dominant or significant third. Psychoanalytic theories from the end of 20th century divide depression into anaclitic and introjective based on psychopathology. Authors in the 21th century showed the neurohormonal, neurochemical, and neuroimmunological background of depression, in a way confirming some of the classic psychoanalytic theories