Abstract:
Wood is one of the conventional materials still used in many engineering applications.
As a natural material, it is subjected to dynamic property variations. One of the major
reasons for the property variation of wood is the moisture absorption. The main aim
of this research is to estimate the degree of decay in the compressive strength of
selected wood types against the amount of moisture using ultrasound waves. Teak
(Tectonagrandis), a hardwood and Pine (Pinusthaeda), a softwood are two types of
wood which are commonly used in Sri Lankan wood industry. Samples of each wood
type were kept for moisture absorption and the ultrasonic pulse velocities were
measured in each sample. A 54 kHz normal probe was used. Through transmission
technique was carried out in longitudinal and transverse directions. The corresponding
compressive strength was also tested for each moisture level in the defined directions.
In the transverse direction, ultrasonic velocity and compressive strength showed
relatively lower values than those in the longitudinal direction. The ultrasound velocity
was found to drop with the increase in moisture content. The rate at which the velocity
drops changed at a particular moisture content. It was noted that this moisture content
is the Fiber saturation point (FSP) of the wood tested. This phenomenon is common
for both the wood types in both the directions. The fiber saturation point of each
sample was confirmed with DSC (Differential Scanning Calorimetric) analysis.
The established relationships can be used to estimate the compressive strength of wood
nondestructively for a known moisture content.
Citation:
Vithanage, V.S.C., Wijesinghe, M.P.M.C., Piyathilake, S.A.K.V.M., & Sivahar, V. (2019). Determination of moisture content of wood using ultrasonic pulse velocity [Abstract]. In V. Sivahar & H.S. Sitinamaluwa (Eds.), Dreams to reality through innovative materials (p. 11). Department of Materials Science and Engineering, University of Moratuwa.