Haava puidu dünaamilise ja staatilise elastsusmooduli võrdlemine erinevatel niiskustasemetel
Laen...
Kuupäev
2014
Kättesaadav alates
Autorid
Pütt, Mario
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Käesolevas bakalaureusetöös käsitletakse haava puidu dünaamilise ja staatilise
elastsusmooduli võrdlemist erinevatel niiskustasanditel. Peale selle uuriti ultraheli
levimise kiiruse ja puiduniiskuse vahelisi seoseid. Töö eesmärgiks oli teada saada,
kuidas sõltub puidu dünaamiline ja staatiline elastsusmoodul ning ultraheli levimise
kiirus puiduniiskusest. Lisaks sellele prognoositi dünaamilise elastsusmooduli ja
tiheduse kaudu purunemismoodulit.
Katsetamiseks kasutati 30 haavapuidust katsekeha, mida viidi kuivatamise teel erinevate
niiskustasemete juurde. Katsekehadel mõõdeti kaal, lineaarmõõtmed ja ultraheli
levimise kiirused kõigis suundades- radiaalses, tangentsiaalses, pikisuunas. Arvutati
ruumala, tihedus, niiskussisaldus ning tiheduse ja ultrahelikiiruste kaudu dünaamiline
elastsusmoodul. Staatiline elastsusmoodul leiti puidukatsemasinaga Instron 3369.
Võrreldi dünaamilise ja staatilise elastsusmooduli, ultraheli levimise kiiruse ja
puiduniiskuse vahelisi seoseid.
Ultraheli levimise kiiruse ja puiduniiskuse vaheline seos osutus üle kiu küllastuspunkti
olevatel niiskustasemetel kõige tugevamaks radiaalsuunas (R=-0,36).
Dünaamilise elastsusmooduli ja puiduniiskuse vaheline seos osutus kõige tugevamaks
üle 30% niiskuse juures pikisuunas (R=0,87).
Staatilise elastsusmooduli ja niiskuse vaheline seos oli kõige tugevam alla 30% niiskuse
juures (R=-0,76).
Purunemismooduli prognoosimisel erinevate argumentide kaudu andis parima prognoosi
dünaamiline pikisuunaline elastsusmoodul üle 30% niiskuse sisaldusega (R=0,575).
The given Bachelor´s thesis deals with aspen wood dynamic and static modulus of elasticity comparison on different moisture levels. Furthermore, it was investigated a relationships of ultrasonic spreading speed and wood moisture. The purpose of this thesis was found out, how wood dynamic and static modulus of elasticity and ultrasonic velocity spreading speed depends on wood moisture. In addition to this, there was predicted a modulus of rupture through the dynamic modulus of elasticity and density. For testing were used 30 aspen wood test specimens, what were bring down to different moisture levels by drying. Test specimens were measured weight, linear dimensions and ultrasonic velocity spreading in all directions- radial, tangential, longitudinal. The cubage, density, moisture content and dynamic modulus of elasticity through the density and ultrasonic velocity were calculated. The static modulus of elasticity was found out with timber test machine Instron 3369. The relationships between dynamic and static modulus of elasticity, ultrasonic velocity spreading speed and wood moisture were compared. The strongest relationship between ultrasonic velocity spreading speed and wood moisture was turned out over the saturation point in radial way (R=-0,36). The strongest relationship between the dynamic modulus of elasticity and wood moisture was turned out in longitudinal way over the 30% of moisture (R=0,87). The relationship between the static modulus of elasticity and wood moisture was strongest below the 30% of moisture (R=-0,76). The best prediction on modulus of rupture predicting through different arguments was given by dynamic modulus of elasticity in longitudinal way with over 30% of wood moisture.
The given Bachelor´s thesis deals with aspen wood dynamic and static modulus of elasticity comparison on different moisture levels. Furthermore, it was investigated a relationships of ultrasonic spreading speed and wood moisture. The purpose of this thesis was found out, how wood dynamic and static modulus of elasticity and ultrasonic velocity spreading speed depends on wood moisture. In addition to this, there was predicted a modulus of rupture through the dynamic modulus of elasticity and density. For testing were used 30 aspen wood test specimens, what were bring down to different moisture levels by drying. Test specimens were measured weight, linear dimensions and ultrasonic velocity spreading in all directions- radial, tangential, longitudinal. The cubage, density, moisture content and dynamic modulus of elasticity through the density and ultrasonic velocity were calculated. The static modulus of elasticity was found out with timber test machine Instron 3369. The relationships between dynamic and static modulus of elasticity, ultrasonic velocity spreading speed and wood moisture were compared. The strongest relationship between ultrasonic velocity spreading speed and wood moisture was turned out over the saturation point in radial way (R=-0,36). The strongest relationship between the dynamic modulus of elasticity and wood moisture was turned out in longitudinal way over the 30% of moisture (R=0,87). The relationship between the static modulus of elasticity and wood moisture was strongest below the 30% of moisture (R=-0,76). The best prediction on modulus of rupture predicting through different arguments was given by dynamic modulus of elasticity in longitudinal way with over 30% of wood moisture.
Kirjeldus
Märksõnad
bakalaureusetööd