Temperature Effect on Ultrasonic Stress Wave Velocity of Wood

목재 초음파 전달속도에 대한 온도의 영향

  • Kang, Ho-Yang (College of Agriculture, Chungnam National University)
  • Received : 1998.11.20
  • Published : 1999.03.30

Abstract

Since ultrasonic stress wave velocity varies with wood temperature and moisture content, ultrasonic stress wave could be a tool to predict wood moisture content if temperature effect could be eliminated. This temperature effect was investigated by measuring the velocities of ultrasonic stress waves transmitting through air, a metal bar and a dimension lumber at various temperatures. For air the velocity and amplitude of the ultrasonic stress wave increase with temperature, while for a metal bar and a dimension lumber those decrease as temperature increases. However all three materials showed velocity hystereses with a temperature cycle. The effect of temperature and moisture content on stress wave velocity of a dimension lumber was depicted in the form of a three dimensional graph. The plot of stress wave velocity vs. wood moisture content was well fitted by two regression equations: a exponential equation below 46% and a linear equation above 46%.

Acknowledgement

Supported by : 한국학술진흥재단