Acoustic properties of wood

U radu je određena brzina širenja zvuka na dvije vrste drva – hrastu i brijestu. Brzina širenja zvuka je jedno od važnijih akustičnih svojstava drva i drugih tehničkih materijala, a ovisi o modulu elastičnosti i gustoći. S obzirom na usmjerenost građe i svojstava drva, sva ispitivanja su provedena u longitudinalnom smjeru, gdje je vrijednost modula elastičnosti najviša. Srednja vrijednost dinamičkog modula elastičnosti za hrast je 17,39 GPa, a za brijest je 10,05 GPa. Gustoća hrasta iznosi 0,759 g/cm3, a brijesta 0,532 g/cm3. Rasipanje rezultata za modul elastičnosti je veliko za obje vrste drva, pogotovo kod uzoraka hrasta. Vrijednost brzine širenja zvuka kod hrasta je za ≈ 10 % viša nego kod brijesta, iako je modul elastičnosti hrasta za 73 % viši od modula elastičnosti za brijest, a gustoća viša za 43 %.In this study, sound velocity was determined between two types of wood – oak and elm. The sound velocity is one of the most important acoustic properties of wood and other technical materials, which is influenced by modulus of elasticity and also density. Depending on the orthotropic structure and properties of wood, all tests were conducted in longitudinal direction in which the modulus of elasticity has the highest value. The mean values of dynamic modulus of elasticity of oak and elm woods were 17,39 GPa and 10,05 GPa, respectively. Density of the oak was 0,759 g/cm3 and density of the elm was 0,532 g/cm3. Scattering of experimental data was large, especially for the oak. The sound velocity of the oak was calculated ≈ 10 % higher than that of the elm, although the modulus of elasticity of the oak were 73 % higher and the density was 43 % higher, in comparison with the elm