Hidromehanički modul u višekriterijskom projektnom modelu brzih brodova

Begović, Ermina (1998) Hidromehanički modul u višekriterijskom projektnom modelu brzih brodova. = Scientific master's thesis , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Grubišić, Izvor.

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Abstract (Croatian)

U radu je napravljen matematički modul za određivanje hidromehaničkih značajki stabiliteta, nepotonivosti i otpora brzih istisninskih i poluistisninskih brodova u konceptualnoj fazi osnivanja broda korištenjem samo izabranih parametara brodske forme. Iz dostupnih podataka o modelima sistematskih serija brzih istisninskih i poluistisninskih brodova reproducirane su glatke brodske forme, definirane u identičnom koordinatnom sustavu. Svi parametri brodske forme su preformulirani u skladu s usvojenom definicijom koordinatnog sustava. \Napravljena je opsežna analiza bezdimenzionalnih parametara brodske forme istražujući njihovu međusobnu funkcionalnu zavisnost. Dobiveni rezultati analize parametara korišteni su kao polazna točka za postavljanje regresijskih modela pri čemu je nužan uvjet da su varijable stabilnog regresijskog modela međusobno nekorelirane. Za razmatranje stabiliteta prvo su načinjeni proračuni S-krivulja i poluga statičkog stabiliteta. Rezultati proračuna su analizirani i prikazani u bezdimenzionalnom obliku da bi se za njihov opis mogla koristiti tehnika regresijske analize. Pretpostavljeni su regresijski modeli za aproksimaciju krivulje poluga statičkog stabiliteta i putanju težišta istisnine i metacentra broda pri nagibima broda od 0=900. Za razmatranje nepotonivosti oštećenog broda razmatra se naplavu krmenog dijela, za jednake iznose naplavljene duljine i varirajući koeficijent permeabiliteta u dva stupnja za sve modele. Iz objavljenih rezultata eksperimentalnog ispitivanja otpora, prema literaturi [1=121 otpori svih modela svih serija proračunati su na CT modela korištenjem istog nadina koji i originalna publikacija sugerira. Koeficijent ukupnog otpora CT tada je prikazan kao funkcija F\N. Vrijednosti koeficijenta otpora trenja Cr izračunate su prema ITTC-57, pa su dobiveni koeficijenti preostalog otpora zbog uniformnog prikaza i daljnje analize interpolirani na iste vrijednosti F\N. Istraženi su regresijski modeli za opis koeficijenta preostalog otpora za svaki FN. Od pretpostavljenih regresijskih modela promatranih fenomena izabran je onaj s najmanjim srednjim odstupanjem. Za sve osnovne modele ponovljeni su proračuni s izabranim regresijskim modelima i prema ovoj usporedbi dani su zaključci. Regresijski model za prognozu otpora testiran je i za 3 broda: Fung 1987, Fung 1991 i Turbinia, koji nisu sadržani u bazi podataka.

Abstract

In this thesis moduli for predicting stability, floodable length and resistance of fast displacement and semidisplacement ships in conceptual phase of ship design have been formulated. From the available data of models of systematic series of fast displacement and semidisplacement ships, faired hull forms has been reproduced and defined in unique coordinate system. All parameters are defined according to new definition of coordinate system. Detailed analysis of the hull form parameters has been carried out in order to find correlation between them. Necessary condition for stable regression model is independence of variables of the model. Obtained results of correlation analysis have been used for formulating a stable regression model. For stability analysis S-curves and righting arm calculations were done for parent hulls of systematic series. Results of these calculations were analysed and transformed in nondimensional form in order to use regression analysis technique. Regression models for approximation and prediction of righting arm curve and trajectory of center of buoyancy and metacenter were assumed for heeling angles of 0 and 90 degrees. For floodable length analysis damage of aft part of parent hulls of systematic series was treated with the variation of floodable length and two coefficients of permeability. From the [1,12] results of resistance tests of systematic series, resistance of all models was recalculated in the form of total resistance coefficient CT according to proposed way in original publication. They were presented as a function of Froude number FN. The values of friction coefficient were calculated according to ITTC-57 correlation line. Residual resistance coefficients were interpolated on the constant values of FN to get uniform database for further analysis. Regression models for CR were formulated for every FN. From all regression models for stability, floodable length and resistance, one with the smallest standard error were chosen. For all parents hulls calculations were repeated with the chosen regression model and conclusions were obtained according to comparison of predicted and original values. Regression model for predicting residual resistance coefficient was tested on three ships: Turbinia (1897), Fung (1987) and Fung (1991) which were not contained in database.

Item Type: Thesis (Scientific master's thesis)
Uncontrolled Keywords: hidromehanički modul; regresijski model
Divisions: 600 Department of Naval Engineering and Marine Technology > 610 Chair of Hydromechanics of Marine Structures
Date Deposited: 22 Sep 2014 18:00
Last Modified: 16 Oct 2015 13:20
URI: http://repozitorij.fsb.hr/id/eprint/64

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