Vibrational Properties of Japanese Cedar Juvenile Wood at High Temperature

The vibrational properties of Japanese cedar wood at high temperature were measured. The specimen, its support system, a magnetic driver, and a deflection sensor were placed in an electric drying oven, where vibration tests were conducted. The heating temperatures ranged from 25 degrees C to 200 degrees C in 25 degrees C increments. The resonance frequency decreased with higher heating temperature and decreased most dramatically in the temperature range of 150 degrees C to 200 degrees C. The loss tangent had a minimum value at 100 degrees C and changed more in the temperature range from 150 degrees C to 200 degrees C than in the range from 25 degrees C to 150 degrees C. The changes in the resonance frequency and loss tangent of the specimens with larger distance from the pith (d) were smaller than those around the pith. These tendencies are believed to have occurred because the portion with a larger d had a smaller number of intercellular layers than the portion around the pith.