목재의 마이크로파 건조과정의 동탄성적 특성

Properties of Dynamic Elasticity of Wood during Microwave Drying

This study was performed to investigate the properties of dynamic elasticity and internal friction during microwave irradiation drying. Three species, red pine(Pinus densiflora Siebold et Zuccarini), chestnut tree (Castanea crenata Siebold et Zuccarini) and black locust(Robinia pseudoaccacia Linnaeus)were tested with three heating conditions(l, 2 and 3 minutes repeated treatment). The res 띠ts were summarized as follows: 1. The dynamic modulus of elasticity(DMOE), in all the other conditions except the heating conditions for 2 and 3 minutes of red pine, had a tendency to decrease as wood moisture content decreased till 20% moisture content and then increase. The DMOE of red pine dried to the target moisture content was similar or a little higher than that of the green red pine. However, in case of chestnut tree and black locust the DMOEs of the specimens dried to the target moisture content were lower than those of green specimens The DMOEs of chestnut tree specimens treated for 2 and 3 minutes decreased with the ratio of about 0.9 as compared with those of the green specimens. 2. The internal friction(IF) had a tendency to increase and then decrease as wood moisture content decreased during microwave heat treatment 때 d the IF of red pine was generally higher than that of black locust. 3. The drying rate during microwave heat treatment depended not on the number of heat treatment applied but on the total heat treatment time. There was no significant difference between heat treatment times required to dry each species to target moisture content, even though each species had different green moisture content.