Određivanje j faktora kod globalnih vertikalnih vibracija brodskog trupa

master's thesis

• Title (english): Determination of j factor for global vertical hull-girder vibration
• Author: Helena Galić
• Mentor: Joško Parunov (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-12-04, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Shipbuilding

Abstract

Dodatna hidrodinamička masa premašuje istisninu broda čak i do 60 %, te ima značajan utjecaj na iznos prirodnih frekvencija vibriranja trupa. U uvodnom dijelu razmatran je teorijski i numerički pristup računanju dodatne mase za vertikalne vibracije. Tradicionalna metoda za određivanje dodatne mase uključuje određivanje sekcijske dodatne mase za dvodimenzionalne poprečne presjeke uzduž broda te očitanje J redukcijskog fakora trodimenzionalnog strujanja iz Lewisovog dijagrama. Tradicionalni J faktori su određeni za pojednostavljene brodske forme. Dobivanje J faktora za suvremene brodske forme opisano je u analizi šest brodskih modela uključujući tankere, kontejnerske brodove, te jedan ratni brod. Nakon proračuna dodatne mase u programskom paketu Femap-Nastran slijedi teorijsko određivanje J faktora. Nakon analize rezultata prikazani su diskusija i zaključak.

Abstract (english)

Added mass exceeds the displacement of the ship up to 60 %, and has a significant impact on the natural frequencies of hull girder vibration. The introductory part is dealing with theoretical and numerical approach to calculation of added mass for vertical vibration. Traditional method for calculating added mass includes determination of two-dimensional coefficient for cross- sectional segments along the ship, and determination of three-dimensional coefficient from Lewis diagram. Traditional J factors have been identified for simplified hull forms. Calculation of J factor for modern hull forms is described in the analysis of the six ships model including tankers, containers and one ware ship. After calculation of added mass, by using software package Femap-Nastran follows the theoretical determination of the J factor. After analysis of the results, discussion and conclusion are given.

• Keywords: dodatna masa; vertikalne vibracije; J faktor; Lewisova metoda; Femap-Nastran
• Keywords (english): added mass; vertical vibration; J factor; Lewis metod; Femap-Nastran
• Language: croatian
• URN:NBN: urn:nbn:hr:235:562621
• Study programme: Title: Naval Architecture; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka brodogradnje (magistar/magistra inženjer/inženjerka brodogradnje)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-27 14:00:52