Σύγχρονος σχεδιασμός της μεταλλικής κατασκευής πλοίων bulk carrier

174 σ.Στο πρώτο κεφάλαιο της διπλωματικής με τίτλο «σύγχρονος σχεδιασμός της μεταλλικής κατασκευής πλοίων bulk carrier», γίνεται προσπάθεια να εξοικειωθεί ο αναγνώστης με την έννοια της σχεδίασης της μεταλλικής του bulk carrier. Το δεύτερο κεφάλαιο αποτυπώνει τις βασικές αρχές που ακολουθούνται στο σχεδιασμό της μεταλλικής κατασκευής των χώρων φορτίου, ξεκινώντας από την περιγραφή της διαδικασίας, που είναι υποσύνολο της σπειροειδούς διαδικασίας κατά τη μελέτη του πλοίου.Το τρίτο κεφάλαιο είναι αφιερωμένο στον προσδιορισμό των φορτίων που επηρεάζουν την κατασκευή του πλοίου. Στο τέταρτο κεφάλαιο της διπλωματικής, γίνεται η παρουσίαση των υπολογισμών, σύμφωνα με τους κανονισμούς του Αμερικανικού Νηογνώμονα (ABS), για τη διαστασιολόγηση των στοιχείων που απαρτίζουν τη μεταλλική κατασκευή του bulk carrier, στην περιοχή της μέσης τομής. Το πέμπτο κεφάλαιο ασχολείται με την ανάλυση της αντοχής του πλοίου. Το έκτο κεφάλαιο επικεντρώνει στο συνολικό σχεδιασμό της μεταλλικής κατασκευής στην περιοχή των αμπαριών, όπως αυτή επηρεάζεται από τα λειτουργικά χαρακτηριστικά και τις ανάγκες που παρουσιάζονται κατά την επιχειρησιακή λειτουργία του πλοίου. Τέλος, στο έβδομο κεφάλαιο παρουσιάζονται όλα τα εναλλακτικά σχέδια της μορφής της μεταλλικής κατασκευής των bulk carrier που έχουν προταθεί τα περασμένα χρόνια, ενώ καταγράφονται και οι κυριότερες περιοχές καινοτομιών που μελετώνται και είναι υπό εξέταση η εφαρμογή τους στη λειτουργία του πλοίου.In the first chapter of this thesis an effort is being made to familiarize the reader on the concept of the bulk carrier design. The second chapter outlines the design principles followed in the structural design of the cargo spaces of a bulk carrier, starting from the structural design process, that is part of the design spiral. The third chapter mentions the determination of loads affecting the hull structure. In the fourth chapter, the calculations for the structural components in the midship section area of a bulk carrier are presented, whereas the fifth chapter of this study copes with the strength analysis of the hull structure. The sixth chapter copes with the overall design of the hold area in a bulk carrier, seen from an operational point of view. Finally, the seventh chapter outlines the main alternative designs that have been implemented last decades in bulk carrier structural design, whereas the major areas of concern for the design of the future are also listed.Σπανολιός Παντελεήμω

Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination

H.L Hunley was a submarine of the Confederate States of America that participated in the American Civil War. On February 17, 1864, H.L.Hunley created history by becoming the first submarine to sink a enemy ship after its attack on USS Houstanic. After Hunley never returned to the shore and the details of its wreck were unknown. On August 8, 2000, H. L Hunley was brought to the surface after 136 years of its wreckage. The submarine is currently at the Warren Lasch Conservation Center located in Charleston. This study focuses on the structural analysis of the H.L Hunley submarine to predict stresses and potential structural failure. Modeling the structure is challenging because of (1) the lack of symmetry due to its current position, (2) non-uniformity due to high corrosion, and (3) the riveted connections with more than 4000 rivets. Although connections between plates in ships are generally considered stronger and stiffer than the rest of the structure, this assumption is assumed to be invalid in the case of the Hunley because of the high and non-uniform corrosion. Since modeling the entire submarine and its 4000 rivet is impossible, the purpose of this study is to create a coordination procedure between the global model of the submarine with simplified connections and the local model of a riveted connection to affectively predict the stresses. The Global model is the whole submarine modeled using shell elements to decrease complexity. The local model consists of one of the riveted connections in the submarine. The validation of the procedure is discussed

Fracture toughness testing data. A bibliography

This bibliography is comprised of approximately 800 reference citations related to the mechanics of failure in aerospace structures. Most of the references are for documents that include fracture toughness testing data and its application or documents on the availability and usefulness of fracture mechanics analysis methodology. The bibliography represents a search of the literature published in the period April 1962 through April 1974 and is largely limited to documents published in the United States

A Review Assessment of Fiber-Reinforced Polymers for Maritime Applications

Composite materials, comprised of fiber-reinforced polymer, offer a high strength-to-weight ratio, making them excellent for the building of complex, lightweight structures in a variety of industries, including the marine sector. There is an improvement in fuel efficiency and cost-effectiveness in general marine component developments as a result of the lightweight and flexible design characteristics. Fiber-reinforced polymer (FRP) composites are often used to construct boats, ships, and other marine compounds, such as the hull, column beams, piling structures, and other internal ship components, since they meet the aforementioned characteristics. In terms of durability, rigidity, and corrosion resistance, these FRPs may readily replace conventional metal counterparts.So,this review gives an overview of FRP Composites usage in marine industries for various potential application.Fiber-reinforced polymer composites offer a significant advantage in strength and weight when compared to conventional materials. Costs are declining and production times are slowly decreasing for maritime components because of their less weight and greater adaptability. &nbsp

The effect of increasing the thickness of the ship’s structural members on the Generalised Life Cycle Maintenance Cost (GLCMC)

In the context of the EU funded IMPROVE project, the research work of a Generalised Life Cycle Maintenance Cost (GLCMC) was initiated in order to investigate the influence of a weight oriented ship structural design on its production and operational characteristics. Following this, an increase in the structural scantlings of the ship was examined following the IACS Common Structural Rules (CSR) for double hull oil tankers. A case study for a Chemical tanker is shown considering an addition in its bottom plate thickness and three different cases of mean annual corrosion rates applied. A comparison regarding the “Gross gains”, “Gross expenses” and “Net gains” for this ship is also presented. Moreover, an evaluation of the extra cost for the additional steel weight used is shown together with the outcome on the repair-free operation of the ship for different additional plate thickness. Finally, a sensitivity analysis is carried out for the most likely case (“Case 2”) and the variation of different amount of days spent in the ship repair yard

Sensitivity study of dynamics variability for mild-carbon steel structures affected by corrosion

Background: Corrosion propagation mainly occurs due to environmental conditions and to the absence of adequate maintenance. The corrosion propagation affects the structural performances of slender and thin structures, in particular in the case of structure very sensitive to the wind action and its dynamical phenomena, because commonly they are designed with a precise optimization of the stiffness/mass ratio. The static and dynamic wind action represent an immediate safety hazard in the case of structural stiffness and mass reduction due to the corrosion depth. Objective: This paper discusses the dynamics behavior variability due to the corrosion depth propagation for two significant examples of slender and thin structure (i.e. tower and truss roof). Methods: The structures assumed as case of study are made of mild carbon. The corrosion depth variability was estimated based on literature references. The structural natural frequencies and modal shapes are assumed as significant magnitudes to discuss the effect of the corrosion on the structural elements. Results: Results have shown that the corrosion depth gives a significant reduction of frequencies and modification of modal shapes. Conclusion: Results have shown that the corrosion depth affect the structural behavior long before a structural collapse. It suggests that a monitoring must be done to estimate the structure reliability for the Serviceability limit state under Characteristic design loads

2016 Scholarly Productivity Report

https://scholarsmine.mst.edu/care-scholarly_productivity_reports/1003/thumbnail.jp

Committee V.1: Accidental Limit States

Concern for accidental scenarios for ships and offshore structures and for their structural components leading to limit states. Types of accidental scenarios shall include collision, grounding, dropped objects, explosion, and fire. Attention shall be given to hazard identification, accidental loads and nonlinear structural consequences including strength reduction, affecting the probability of failure and related risks. Uncertainties in the use of accidental scenarios for design and analysis shall be highlighted. Consideration shall be given to the practical application of methods and to the development of ISSC guidance for quantitative assessment and management of accidental risks

Cargo transportation by airships: A systems study

A systems engineering study of a lighter than air airship transportation system was conducted. The feasibility of the use of airships in hauling cargo was demonstrated. Social, legal, environmental and political factors were considered as well as the technical factors necessary to design an effective airship transportation system. In order to accomplish an effective airship transportation program two phases of implementation were recommended. Phase I would involve a fleet of rigid airships of 3.5 million cubic feet displacement capable of carrying 25 tons of cargo internal to the helium-filled gas bag. The Phase I fleet would demonstrate the economic and technical feasibility of modern-day airships while providing a training capability for the construction and operation of larger airships. The Phase II portion would be a fleet of rigid airships of 12 million cubic feet displacement capable of carrying a cargo of 100 tons a distance of 2,000 miles at a cruising speed of 60 mph. An economic analysis is given for a variety of missions for both Phase I and Phase II airships