Kuusepuidu uurimine pikki-ja ristikiudu survele ning pikikiudu paindele kasutades EN, ISO ja ASTM standardeid
Laen...
Kuupäev
2021
Kättesaadavus
09.06.2026
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Harilik kuusk (Picea abies) on Eestis üks enim levinumaid puuliike, mille töötlemisel
saadakse suurem osa ehituses kasutatavat puitu ning seetõttu peame olema kursis
kuusepuidu üldiste tugevusomadustega ja tundma nende kasutusvõimalusi.
Töös võrreldakse kuusepuidu füüsikalis-mehaanilisi omadusi kasutades EN, ISO ja
ASTM standardite katsemetoodikaid ning määratakse survetugevust ristikiudu
sõltuvalt materjali kõrgusest ja surutava pinna suurusest.
Katsekehade valmistamiseks kasutati Eestis kasvavat kuusepuitu, mis on toodetud
Stora Enso Eesti saeveskist. Kokku valmistati ligi 1100 erineva suurusega ja eri
katseseeriateks mõeldud katsekeha. Katseseerias oli 44 katsekeha.
Töös uuritud katsekehade keskmine tihedus oli 454 kg/m3
.
Ristikiudu survetugevuse katsetamisel andsid kõige suurema survetugevuse väärtuse
standardi ASTM D143 järgi katsetatud katsekehad. Eelpool mainitud standardi ja
standardi ISO 3132 tulemused olid omavahel sarnased. Standardite EN 408, EN14374
ja ISO 13061-5 põhjal tehtud katsete tulemused olid omavahel peaaegu sarnased aga
ASTM ja ISO 3132 standardiga võrreldes peaaegu kaks korda väiksemad.
Paindetugevuse võrdluses olid ligilähedaselt sarnased EN 408 ja ISO 13061-3 nõuete
järgi tehtud katsetulemused ning ASTM D143 standardit kasutades saadi märgatavalt
väiksem paindetugevuse väärtus. Katsetades puidu survetugevust ristikiudu erinesid
keskmised tulemused vähem kui 10%.
Antud lõputöö katsete tulemused näitavad, et kasutades erinevaid standardeid saadakse
ka erinevad surve- ja paindetugevuse näitajad isegi samast prussist lõigatud puidu
korral. Ristikiudu survetugevuse katsetamisel ilmnes seos katsekehade paksusmõõtude
ning surutava pinna suuruse muutusest. Katsestandardeid tuleb kasutada koos vastava
riigis kehtivate normidega, et tugevusarvude käsitlus oleks õige.
Norway spruce (Picea abies) is one of the most common tree species in Estonia, and most of the timber used in construction is processed from it, so we need to be familiar with the general strength properties of spruce and its potential uses. The work compares the physical-mechanical properties of spruce timber using the test methodologies of EN, ISO and ASTM standards and determines the compressive strength perpendicular the grain depending on material height and the size of the compressed surface. The test samples were made from spruce wood grown in Estonia and produced by Stora Enso's sawmill in Estonia. In total, about 1100 test specimens of different sizes and for different test series were produced. There were 44 test specimens in the test series. The average density of the test specimens was 454 kg/m3 . The compressive strength tests perpendicular to the grain tested by ASTM D143 gave the highest compressive strength value. The results of the above standard and ISO 3132 were similar. The results of the tests carried out on the basis of EN 408, EN14374 and ISO 13061-5 were almost similar but almost twice as low as those of ASTM and ISO 3132. In the comparison of bending strength, the test results performed according to the requirements of EN 408 and ISO 13061-3 were approximately similar, and using the ASTM D143 standard, a significantly lower value of bending strength was obtained. Testing timber to the strength perpendicular to grain mean results over all tests differed less than 10%. The results of the tests in this thesis show that using different standards also gives different compressive and bending strength values, even for the samples cut from the same solid timber. In the case of the compression strength testing perpendicular to the grain, a correlation between the variation in the thickness of the test specimens and the size of the compressive surface was observed. Test standards should be used in conjunction with the relevant national standards to ensure that the strength values are used correctly.
Norway spruce (Picea abies) is one of the most common tree species in Estonia, and most of the timber used in construction is processed from it, so we need to be familiar with the general strength properties of spruce and its potential uses. The work compares the physical-mechanical properties of spruce timber using the test methodologies of EN, ISO and ASTM standards and determines the compressive strength perpendicular the grain depending on material height and the size of the compressed surface. The test samples were made from spruce wood grown in Estonia and produced by Stora Enso's sawmill in Estonia. In total, about 1100 test specimens of different sizes and for different test series were produced. There were 44 test specimens in the test series. The average density of the test specimens was 454 kg/m3 . The compressive strength tests perpendicular to the grain tested by ASTM D143 gave the highest compressive strength value. The results of the above standard and ISO 3132 were similar. The results of the tests carried out on the basis of EN 408, EN14374 and ISO 13061-5 were almost similar but almost twice as low as those of ASTM and ISO 3132. In the comparison of bending strength, the test results performed according to the requirements of EN 408 and ISO 13061-3 were approximately similar, and using the ASTM D143 standard, a significantly lower value of bending strength was obtained. Testing timber to the strength perpendicular to grain mean results over all tests differed less than 10%. The results of the tests in this thesis show that using different standards also gives different compressive and bending strength values, even for the samples cut from the same solid timber. In the case of the compression strength testing perpendicular to the grain, a correlation between the variation in the thickness of the test specimens and the size of the compressive surface was observed. Test standards should be used in conjunction with the relevant national standards to ensure that the strength values are used correctly.
Kirjeldus
Magistritöö
Maaehituse õppekaval
Märksõnad
magistritööd, harilik kuusk, tihedus, survetugevus ristikiudu, survetugevus pikikiudu, paindetugevus