Αντοχή καταστρώματος οχημάτων κατά την διάρκεια πυρκαγιάς

Danopoulos, Charalampos; Δανόπουλος, Χαράλαμπος

dc.contributor.author	Danopoulos, Charalampos	en
dc.contributor.author	Δανόπουλος, Χαράλαμπος	el
dc.date.accessioned	2024-02-02T11:12:43Z
dc.date.available	2024-02-02T11:12:43Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/58765
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.26461
dc.rights	Default License
dc.subject	Θερμικές τάσεις	el
dc.subject	Πυρκαγιά	el
dc.subject	Πεπερασμένα στοιχεία	el
dc.subject	Ανυψωμένη θερμοκρασία	el
dc.subject	Προσομοίωση πυρκαγιάς	el
dc.subject	Finite element analysis	en
dc.subject	Fire	en
dc.subject	Fire simulation	en
dc.subject	Elevated temperature	en
dc.subject	Thermal stresses	en
dc.title	Αντοχή καταστρώματος οχημάτων κατά την διάρκεια πυρκαγιάς	el
dc.title	Structural strength of car deck during fire	en
heal.type	bachelorThesis
heal.classification	Πυρκαγιά σε κατάστρωμα οχημάτων	el
heal.language	en
heal.access	campus
heal.recordProvider	ntua	el
heal.publicationDate	2023-10-03
heal.abstract	The purpose of this thesis is to analyze a fire that occurred on the car deck of a passenger ship. The objective is to assess possible scenarios for the initiation and spread of the fire and then to predict the structural response. For our scenarios, we assumed that the cause of the fire was a spark originating from a truck. This scenario is not at all a random choice, as in recent years most fires had their starting point in trucks, their cooling systems and the transported cargo. More specifically, the truck is engulfed in flames and within a short period of time the fire is transferred to the adjacent vehicles. For the fire simulation, the model included all the car deck area, in its entire length and breadth, the upper deck and a part of the side hull from the upper deck and the deck below. All the obstructions were also modeled and the trucks were placed in specific positions based on the ship’s plans. The model was created in the fire simulation environment Pyrosim, which was used to calculate the effect of the heat released by the truck to the deck area. Pyrosim is a user-friendly program with many features and it’s a useful tool for estimating the temperature of a material. The program is solving the Navier-Stokes equation in order to calculate the temperature in each node of the model and provides the option to calculate the heat transfer in different objects based on the properties that the user provides. There are different types of sensors and devices depending on the quantity the user wants to determine. In this thesis, the temperature in the steel plates is under study and in order to calculate it, a set of sensors was placed all over the heat affected area. Subsequently, finite element analysis was used, in order to estimate the stresses and the elongations of the deck. The upper deck of the previous simulation was modeled. The temperatures in that deck were significantly higher compared to the floor deck where the truck caught fire. Hot gases and radiation were affecting the plates and the temperature of the upper deck was rising exponentially. The temperature data were imported from the previous simulation to the program ABAQUS that was used for the FEA simulation. It was assumed that the passenger ship was at its maximum capacity. As a result, the modeled deck was full of vehicles, applying pressure to the plates. The vehicle's gravitational load and a small axial displacement was first applied to the structure, in order to simulate the pre-existed stresses of the deck. In general, a deck is designed to carry the preexisting loads without any danger, so the stresses are small and cannot plastically deform the steel plates. However, the steel ‘softens’ in high temperatures. In other words, the steel’s properties change with the temperature increase, minimizing the ultimate stresses and deforming plastically the steel over time. Temperature change also affects the structure due to the steel’s thermal expansion properties. A temperature change of 150 degrees Celsius or higher is enough for steel to surpass its yield strength and deform plastically. In this thesis, two possible scenarios were studied. In the first scenario, a completely enclosed deck was modeled, in which the fire starts expanding and gradually self-extinguishes. In the second model, on the same deck an external airflow is applied. The airflow simulates the existence of ventilation in the space, supplying the fire with fresh air. In the vehicle area there is a constant air supply, the specifications of which are defined by international regulations. For each case, the temperatures near the burning truck were measured and the effects of the heat transferred to the plates were estimated.	en
heal.advisorName	Σπύρου, Κωνσταντίνος	el
heal.advisorName	Σαμουηλίδης, Εμμανουήλ	el
heal.committeeMemberName	Θεμελής, Νικόλαος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Μελέτης Πλοίου και Θαλάσσιων Μεταφορών	el
heal.academicPublisherID	ntua
heal.numberOfPages	77 σ.	el
heal.fullTextAvailability	false