Contribution of the Croatian Academy of Sciences and Arts to the Development of Marine Technology in Croatia

Contribution of the Croatian Academy of Sciences and Arts to the development of marine technology in Croatia is described in this paper. Intensive research and development of marine technology in Croatia was initiated by Prof. Zlatko Winkler, fellow of the Croatian Academy of Sciences and Arts, in 1979 when the first Conference on Marine Technology was organized. Since 2005 the Conference on Marine Technology is organized by the Scientific Council of Maritime Affairs of the Croatian Academy of Sciences and Arts and the Faculty of Engineering in Rijeka in memory of Zlatko Winkler (1917 – 1996), president of the Scientific Council of Maritime Affairs between 1994 and 1996. Grateful for his contribution to the research and development, the Croatian Academy of Sciences and Arts continuously and generously supports the conference organization. Until today in total seven Conferences on Marine Technology were organized. As pointed out in the paper, the most important contribution of the Academy to development of the marine technology is organization of round tables on this challenging topic

Nonlinear Ship Rolling and Capsizing

The existing level of ship safety rules is presented and analysed, and guidelines for upgrading and improving the rules are given. An uncoupled equation of ship rolling is set and the methods for solving nonlinear ship rolling in regular and irregular waves are presented. Calculations of rolling for a particular ship in regular and irregular waves are done using the harmonic acceleration method. Nonlinear response phenomena are analysed. Capsizing probability is calculated by means of nonlinear dynamics (basin erosion technique). Based on these calculations new criteria for ship stability are recommended, based on the use of the ship survivability diagrams

Strukturna analiza broda za prijevoz općeg tereta

Svrha rada je prikazati postupak i najvažnije rezultate strukturne analize broda za prijevoz općeg tereta nosivosti 2240 dwt. Primijenjen je postupak modeliranja cijelog broda metodom konačnih elemenata. Osnovni problem koji se analizira je torziono ponašanje brodske konstrukcije s velikim palubnim otvorom i koncentracija naprezanja koja se kao posljedica javlja na uglovima grotla. Proračun globalne čvrstoće je proveden koristeći “grubu mrežu” konačnih elemenata, dok su područja u kojima se javljaju koncentracije naprezanja usitnjena fi nom mrežom konačnih elemenata. Studija pokazuje primjenu metode konačnih elemenata kao alata za poboljšanje sigurnosti konstrukcije broda za prijevoz općeg tereta

Konceptualno projektiranje cilindričnog dijela čvrstog trupa podmornice

Cilj ovog rada je prikazati mogućnost konceptualnog projektiranja konstrukcije cilindričnog trupa podmornice. Poznavanjem tehnoloških mogućnosti i projektnih zahtjeva smanjen je broj projektnih varijabli pa je moguće problem riješiti u trodimenzionalnom prostoru što omogućuje analitičko i grafičko rješavanje problema. Strukturne dimenzije proizašle optimizacijom provjerene su metodom konačnih elemenata u koju svrhu je napravljen model cilindričnog trupa s integriranim strukturnim tankom. U optimizaciji čvrstog trupa nisu uzeti u obzir utjecaji realnih dodataka kao što su pregrade, integrirani tank, pražnica i greda, koji su modelirani i ispitani pomoću MKE kako bi prikazali moguće utjecaje dodataka na trup

Remedy for Misalignment of Bilobe Tank Heads in Liquefied Petroleum Gas Carrier

The article describes the remedy for a misalignment of Y-joint in hemispherical and torispherical heads of the bilobe cargo tank on a Liquefi ed Petroleum Gas Carrier. The misalignment is the result of connecting relatively thin shells and production diffi culties. The measured rather large shell eccentricity in the Y-joint causes bending moment, which cannot be withstood by shells designed as membrane, and therefore it has to be controlled. The remedy of misalignment is achieved by reinforcement of the Y-joint with inside and outside bars and knees. In this way stress concentration determined by the FEM analysis is reduced within the allowable stress given for secondary stress level