• Journal of the Korean Wood Science and Technology
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• v.31 no.2
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• pp.31-37
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• 2003

Among the nondestructive evaluation (NDE) methods for wood defect detection, ultrasonic wave has been considered as competitive technique in terms of economics and workability. Until now, researches on application of NDE methods for wood have focused mainly on standing tree and logs. Recently, some attempts have been conducted with NDE technique, for evaluation of wooden structural members. However, wooden structural members are different from others (standing tree or log) in various aspects. Expecially when some parts or whole member are covered with other materials, they can't be evaluated appropriately on general NDE methods. For the purpose of development of proper NDE technique for the wooden structural members, the ultrasonic wave transmission process investigated on artificial defect in wood. First, various types of transmission process were assumed, and then the transmission times were predicted respectively. Predicted times were compared with the measured time of ultrasonic wave and then a suitable type of transmission process is determined. In case of the ultrasonic wave doesn't transmit directly due to defect, it is reflected once only at the opposite surface of member, and the path is accord with the line of shortest length.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.74-81
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• 2004

The ultrasonic non-destructive method was used for wood decay test. The temperature change and moisture contents of wood were estimated how the ultrasonic wave velocity changes. The relationship between weight loss of wood decayed by T. palustris and ultrasonic wave velocity was investigated. The non-destructive methods of different condition of logwood were estimated. Decay map of old wood was made by non destructive methods. Through these tests, we can accumulate the data to judge the degree of wood decay. The decay map of wood could be used for the analysis of old wood.