Numerično iskanje optimalne oblike ploskovnih konstrukcij

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Language:	Slovenian
Year of publishing:	2007
Source:	Ljubljana
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
Publisher:	[M. Jaklič]
UDC:	624.073(043.2)
COBISS:	3820897
Views:	2166
Downloads:	661
Average score:	0 (0 votes)
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Secondary language:	English
Secondary title:	Numerical shape optimization of shell structures
Secondary abstract:	In this graduation thesis a numerical shape optimization of shell structures is considered. Parameterization of the shape of surface construction by a Bézier body as a design element is described in detail. The finite element mesh depends on the changes of parameters of the design element. The optimization consists of iterative minimization of the object function considered. The program EKON for the analysis of elastic constructions by FEM is used. The optimization step is done by the program iGO, which is based upon the gradient method. Special cases of numerical shape optimization of shell structures by minimization of strain energy and various constrains (construction volume, position of a point in a construction, etc.) are shown. Various models of the same construction with different number of project elements and project variables are described. Besides geometric linear cases, also the numerical optimization of geometrical nonlinear cases are considered and compared with the linear ones. Program SAP2000 is used for the geometric nonlinear analysis and the analysis of the buckling resistance. An algorithm for the export of the geometry of the construction from EKON to SAP2000 is given.
Secondary keywords:	civil engineering;graduation thesis;shell structures;thin shells;shape optimization;
File type:	application/pdf
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages:	XI, 69 str., pril.
Type (ePrints):	thesis
Title (ePrints):	Numerical shape optimization of shell structures
Keywords (ePrints):	ploskovne konstrukcije;lupine;optimizacija oblike
Keywords (ePrints, secondary language):	shell structures;thin shells;shape optimization
Abstract (ePrints):	Diplomska naloga obravnava določitev optimalne oblike ploskovnih konstrukcij. Podrobno je opisan postopek parametrizacije ploskovne konstrukcije s t.i. Bézierovim telesom, ki ga imenujemo tudi projektno telo. Spremembam parametrov projektnega telesa sledi tudi mreža končnih elementov. Optimizacija vrednosti parametrov poteka z iterativnim postopkom iskanja minimuma namenske funkcije. Uporabljen je raziskovalni računalniški program EKON - program za analizo elastičnih konstrukcij po metodi končnih elementov. Za samo optimizacijo je uporabljen raziskovalni računalniški program iGO, zasnovan na gradientni metodi. Prikazani so primeri numerične optimizacije oblike ploskovnih konstrukcij z uporabo namenske funkcije minimuma deformacijske energije in različnih omejitvenih pogojev (prostornina konstrukcije, pozicija točke konstrukcije, ...). Opisanih je več različnih računskih modelov iste konstrukcije z uporabo različnega števila projektnih elementov in projektnih spremenljivk. Poleg geometrijsko linearnih primerov je za primerjavo prikazana tudi numerična optimizacija geometrijsko nelinearnih primerov. Za kontrolo uklonske nosilnosti optimalne oblike ploskovne konstrukcije je prikazan postopek prenosa geometrije konstrukcije iz programa EKON v komercialni program SAP2000, s katerim je izvedena geometrijsko nelinearna analiza ter analiza uklonske nosilnosti.
Abstract (ePrints, secondary language):	In this graduation thesis a numerical shape optimization of shell structures is considered. Parameterization of the shape of surface construction by a Bézier body as a design element is described in detail. The finite element mesh depends on the changes of parameters of the design element. The optimization consists of iterative minimization of the object function considered. The program EKON for the analysis of elastic constructions by FEM is used. The optimization step is done by the program iGO, which is based upon the gradient method. Special cases of numerical shape optimization of shell structures by minimization of strain energy and various constrains (construction volume, position of a point in a construction, etc.) are shown. Various models of the same construction with different number of project elements and project variables are described. Besides geometric linear cases, also the numerical optimization of geometrical nonlinear cases are considered and compared with the linear ones. Program SAP2000 is used for the geometric nonlinear analysis and the analysis of the buckling resistance. An algorithm for the export of the geometry of the construction from EKON to SAP2000 is given.
Keywords (ePrints, secondary language):	shell structures;thin shells;shape optimization
ID:	8308097