Optimizacija sestave hibridnih lepljenih lameliranih nosilcev

Fašalek, Andrej (author), Šernek, Milan (mentor), Straže, Aleš (comentor)

Les v zadnjih letih ponovno postaja atraktiven gradbeni material zaradi večje ekološke osveščenosti in splošnega trenda okolju prijazne graditve. Ena alternativnih možnosti uporabe bukovega lesa, ki ga imamo v Sloveniji veliko, je izdelava lepljenih lameliranih nosilcev. Zaradi nekaterih pomanjkljivosti, ki jih ima bukov les, je bil cilj magistrske naloge razviti kombiniran nosilec iz bukovine in smrekovine (hibridni nosilec). Vseboval naj bi takšen delež bukovine, da bi njena izkoriščenost bila najvišja z vidika togosti, trdnosti in nizke lastne teže nosilca. Z namenom, da bi ugotovili, ali sta pogosto uporabljani MUF in PUR lepili primerni za izdelavo takšnih nosilcev, smo izvedli strižni in delaminacijski test po standardu SIST EN 14080:2013. Zahteve so bile dosežene v vseh primerih. Izdelali smo po dva bukova, smrekova in hibridna nosilca, ki sta imela zunanji lameli iz bukovine, notranje pa iz smrekovine. Lamelam in nosilcem smo določili dinamični modul elastičnosti. Vpliv deleža bukovine na togost nosilca smo izračunali s kompozitno teorijo. Vpliv na trdnost pa smo preučili s simulacijami, ki smo jih izvedli v programu ABAQUS. Na podlagi izvedenega štiritočkovnega upogibnega testa smo izdelali modele smrekovih in bukovih nosilcev. Za hibridne nosilce smo naredili 12 modelov z različnimi debelinami bukovih lamel. Z vidika togosti in nizke lastne teže nosilca smo ugotovili, da je optimalen delež bukovine v hibridnem nosilcu nič, saj so najvišji specifični modul elastičnosti dosegli smrekovi nosilci. Rezultati, dobljeni pri simulacijah, niso pokazali najboljšega sovpadanja z eksperimentalnimi, zato optimalnega deleža bukovine z vidika trdnosti in nizke lastne teže nismo določili. Ugotovili smo dobro korelacijo med statičnimi in dinamičnimi moduli elastičnosti nosilcev.

• Language: Slovenian
• Keywords: hibridni lamelirani nosilci, nelinearne simulacije, konstrukcijsko lepljenje
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [A. Fašalek]
• Year: 2019
• PID: 20.500.12556/RUL-113416
• UDC: 630*824.89
• COBISS.SI-ID: 3159945
• Publication date in RUL: 02.01.2020

FAŠALEK, Andrej, 2019, Optimizacija sestave hibridnih lepljenih lameliranih nosilcev [online]. Master’s thesis. A. Fašalek. [Accessed 11 June 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=113416

Secondary language

• Language: English
• Title: Gluing of hybrid laminated beams and optimisation with finite element method

Abstract

In recent years, wood has again become an attractive building material, due to increased ecological awareness and the general trend of environmentally friendly construction. One alternative use of beechwood, which is in abundance in Slovenia, is the production of glulam beams. Due to some of the deficiencies of beechwood, the aim of the master’s thesis was to develop a combined beech and spruce glulam beam (hybrid beam), which should contain such a proportion of beechwood so that its utilisation would be optimised in terms of stiffness, strength and lightweight. To find out if the widely used MUF and PUR adhesives are suitable for the production of such beams, shear and delamination tests were performed according to the SIST EN 14080:2013 standard . The requirements were met in all cases. Two beech, spruce and hybrid glulam beams, with outer lamellas from beech and inner lamellas from spruce wood, were made. The dynamic modulus of elasticity was determined for all the used lamellas, as well as the glulam beams. The influence of the proportion of beechwood on the stiffness of a glulam beam was calculated using composite beam theory. However, the impact on the strength was studied by the simulations carried out in the ABAQUS software. Based on the four-point bending test, models of spruce and beech beams were made. For hybrid beams, 12 models with different thicknesses of beech lamellas were created. With regard to the stiffness and lightweight, it was found that the optimum proportion of beechwood in the hybrid beam is zero, since the highest specific moduli of elasticity, were obtained with the spruce beams. The results obtained in the simulations did not show a good agreement with the experimental ones; therefore, the optimum proportion of beechwood in a beam in terms of strength and lightweight was not determined. A good correlation between the static and dynamic moduli of elasticity of the beams was found.

• Keywords: hybrid glulam beams, nonlinear simulations, constructional gluing