Modeling of the translational shells of wood-based lamellae and their model tests

Käesoleva diplomitöö raames uuriti kärbitud ikosaeedri- ning pooliku gloobuse tüüpi koorikkonstruktsiooni püstitamise võimalikkust. Katsekehad valmistati 12 mm kasevineerist, mille detailid lukustati kald-hammaslukkseotist kasutades. Töö eesmärk oli kontrollida ja analüüsida tapigeomeetriat reaalses puitkonstruktsioonis. Konstruktsiooni püstitamiseks tutvuti kirjandusega, pakuti välja seotiste asukohad, valmistati katsekehad, viidi läbi katsed ning analüüsiti saadud tulemusi. Katsed teostati laborites, mis kuuluvad Eesti Maaülikooli Metsandus- ja maaehitusinstituudi maaehituse osakonnale. Kuna puudusid analoogsete katsete käiku reguleerivad riiklikud ning rahvusvahelised standardid, viidi katsed läbi metoodikatega nagu sarnastel katsetel eelnevatel aastatel. Katsete tulemusel selgus, et käsitöö ülafreesi kasutades ei sobi katsekeha detailid omavahel kokku ning nende valmistamise täpsuse suurendamiseks tuleks kasutada NC-faili ning vähemalt viieteljelist arvutiprogrammjuhtimisega CNC töötlemiskeskust. Pooliku gloobuse kujulises katsekeha purunes esimene korrus 22,55 kN vertikaalkoormuse juures. Sellel korrusel oli 16 detaili ning vertikaalne nurk 58˚ ja horisontaalne sisenurk 162,8˚. Teine korrus purunes 14,12 kN vertikaalkoormuse juures ning 16. detailist sobisid ideaalselt kokku 14. Sellisel juhul oli vertikaalne nurk 45˚ ja horisontaalne sisenurk 162,1˚. Kõige väiksema raadiusega kolmanda korruse katsekeha purunes 11,49 kN vertikaalkoormuse saavutamisel. Sellel korrusel sobisid ideaalselt kokku vaid 12 detaili. Detailide vaheline vertikaalne nurk oli 44˚ ja horisontaalne sisenurk 160˚. Kahe esimese korruse puhul kald-hammaslukkseotised ei purunenud, vaid libisesid üksteisest üle. Kolmanda korruse puhul seotis purunes. Katsete käigus selgus, et tappe kooshoidev kinnitusvahend ei olnud õigesti paigaldatud. Selleks, et kald-hammaslukkseotis ei libiseks üle, oleks tulnud paigaldada poldid sisemise lamelliga risti. Sellisel juhul oleks kinnitusvahend tapid ideaalselt koos hoidnud, samuti võimaldanud seotiste omavahelise nihkumise.In this Master’s thesis was investigated the possibilities of erection of shell structures in the form of truncated icosahedron and semi-globe. Specimens were made of plywood (12 mm). The details of specimen were locked to each other by scarf joints. The aim of the work was to verify and analyse the tongue joint geometry in the real timber structure. The preparation to test the structure included acquainting with the literature, suggesting the locations of joints, preparing the test specimens, carrying out the test and analysing the results. The tests carried out in the laboratories that belong to the Department of Rural Building of the Institute of Forestry and Rural Engineering of Estonian University of Life Sciences. Since there are no analogous national and international standards, which would govern the course of the tests, they carried out according to techniques similar to those being used in the previous tests in the previous years. The tests showed that the details of the test specimen what joints made by the handicraft router do not fit together. It would be better in the future to design them by CAD-program and convert it to NC-file. The routing had to done with five-axis CNC-workstation. The ground floor test specimen of the semi-globe broke at vertical load of 22.55 kN. On this floor there were 16 parts, the vertical angle was 58˚ and horizontal internal angle was 162,8˚. The second floor was broke at vertical load of 14,12 kN; 14 parts from 16 matched together perfectly. In this case, the vertical angle was 45˚ and horizontal internal angle was 162,1˚. The test piece of the floor with the smallest radius broke by achieving the vertical load of 11.49 kN. Only 12 parts on this floor matched together perfectly. The vertical angle between the parts of the third floor was 44˚ and the horizontal internal angle was 160˚. The scarf joints of the first two floors did not break, but slipped over each other. On the third floor the joint broke. It became clear during the tests that the fasteners, which held the tongue joints together, was not correctly mounted. In order that the scarf joints would not slip over each other, the bolts had mounted transverse to the inner lamella. In such case, the fastener would perfectly hold the tongue joints together, permitting also the mutual shift of the joints