Fracture toughness improvement in Sugi [Cryptomeria japonica] lamina by hot-pressing
2006
Honda, T.(Yamanashi-ken. Forest Research Inst. (Japan))
Fracture toughness of the lumber which was processed combining heating compression and hot drying was investigated. The mode in the TL system as a fracture toughness Ksub(IC) was measured. In case of the compression of 0.5 Mpa, Ksub(IC) increases in the area below 150 deg C, but Ksub(IC) decreases largely in the area above 180 deg C, and fracture becomes brittle. In addition, also heating time to the increase of Ksub(IC) is relative. In case of the compression of 2.0Mpa, when data compression ratio is high, Ksub(IC) increases remarkably. When it was compressed at above 140 deg C, the minute crack occurs at the time of release pressure, furthermore it seems that receives the influence of the dry temperature that in hot drying. Equilibrium moisture content of these heat treated woods decreased regardless of processing condition such as compression and dry temperature. Because percentage of water content decreases suitably with heating compression, you can expect the reduction of dry time.
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