Kecepatan Rambatan Gelombang Ultrasonim dan Keteguhan Lentur Beberapa Jenis Kayu pada Berbagai Kondisi Kadar Air

Abstract

The ultrasonic method was examined as a means ofevaluating moisture content variation on ultrasonic wave propagation (velocity) and bending strength either dynamic or static test of six tropical woods, i.e, sengon (Paraserianthes falcataria L. Nielsen). manglum (Acacia mangium Willd), durlan (Durio zibethinus Murr), pine (Pinus merkusii Junghuhn & de Vriese). rasamala (Altingia excelsa Noronhae) and kempas (Koompassia malaccensis Maing). Ultrasonic wave velocity measurement and bending strength testing. both dynamic and static were conducted on 20-by 20-by 300 mm small wood clear specimen of several moisture content conditions, The results showed that the mean value ofultrasoniC velocity decreases when the moisture content increase. The dynamic modulus of elasticity (MOEd). static modulus of elasticity (MOEs). and modulus of rupture (MOR) for all wood increase when the moisture content decrease significantly from fiber saturation point to oven dry condition. In case ofequilibrium moisture content, the MOEd values were 35 % percent higher than those MOEs values.