Numerička simulacija kompozitne kobilice

master's thesis

• Title (english): Numerical simulation of composite keel
• Author: Igor Grabar
• Mentor: Tomislav Jarak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2018-01-26, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U diplomskom radu proveden je numerički proračun čvrstoće i stabilnosti kobilice za malu jedrilicu. Model kobilice sastoji se od lista i klizača kobilice. Kobilica je izrađena od kompozitnih materijala. U radu su prikazane osnovne pretpostavke i izrazi mehanike kompozitnih materijala. Proračun je proveden pomoću metode konačnih elemenata (MKE) u programskom paketu Abaqus. U svrhu odabira prikladnih konačnih elemenata koji će se koristiti u proračunu kobilice te da bi se ispitala konvergencija numeričkog rješenja, proveden je verifikacijski proračun na jednostavnom modelu pravokutne ploče. Pravokutna ploča izrađena je od dva jednosmjerna sloja kompozita od E-stakla i epoksidne smole. Provjerena je konvergencija rezultata koji se odnose na čvrstoću i stabilnost ploče. Konvergencija je provjerena korištenjem klasičnih (engl. “Shell“) i kontinuumskih ljuskastih (engl. “Continuum shell“) elemenata. Numerička analiza kompozitne kobilice sastoji se od nekoliko iteracija, kojima se provjerava i traži izvedba koja će zadovoljiti čvrstoću i stabilnost konstrukcije. Prva iteracija sastoji se od proračuna kobilice sa materijalnim svojstvima i svojstvima čvrstoće koja su dobivena procjenom na temelju mikrostrukture materijala. U drugoj iteraciji proveden je proračun sa svojstvima koja su korigirana prema eksperimentalno dobivenim podacima. Nakon toga je u trećoj iteraciji analiziran problem koncentracije naprezanja kod prijelaza s lista na klizač kobilice, a rješenje je dano u obliku radijusnog prijelaza. Četvrta iteracija sadrži model kojem je dodano ojačanje u obliku I-profila na mjesto kontakta kobilice s kutijom kobilice. Ojačanje je potrebno da bi se zadovoljila čvrstoća konstrukcije na tom dijelu. U zadnjoj iteraciji dodana su ojačanja s četverokutnim profilom u svrhu rješavanja problema stabilnosti kobilice.

Abstract (english)

In this thesis a numerical calculation of the strength and stability of the keel boat was carried out. The keel model consists of two parts: fin and a keel slider. The keel is made of laminate composite materials. Some basic assumptions and expressions of composite material mechanics, which are used in the work, are presented. The calculation was performed using the Finite Element Method (FEM) in the Abaqus program package. In order to choose the appropriate finite elements for the keel calculations, and to test the convergence of numerical solutions, a verification calculation was performed on a simple supported rectangular plate model. This rectangular plate is made of two unidirectional composite plies made of E-glass and epoxy resin. Convergence has been verified using the classic shell and continuum shell elements. The numerical analysis of the composite keel consists of several iterations, which are used to find and verify the best solutions that will satisfy the strength and stability of the construction. The first iteration consists of a keel calculation in which the material and strength properties are obtained by using micromechanics. In the second iteration, a calculation with properties corrected according to experimentally obtained data is performed. Then, in the third iteration, the problem of stress concentration at the transition from the fin to the keel slider was solved and the solution was given in the form of a radial transition between two parts. The fourth iteration contains a model on which an I-profile fixing was added at the point of contact of the keel with a keel box. Reinforcement is needed to meet the strength criteria of this part of the keel. The last iteration was the addition of fixings with a quadrilateral profile (which follows the hydrodynamic profile of the keel fin) for the purpose of securing the keel stability.

• Keywords: jedrilica; kobilica; kompozit; mikromehanika; laminat; metoda konačnih elemenata
• Keywords (english): sailboat; keel; composite; micromechanics; laminate; finite element method
• Language: croatian
• URN:NBN: urn:nbn:hr:235:038293
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 21:23:52