Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Development of Portable X-ray CT System I - Evaluation of Wood Density using X-ray Radiography -

현장 적용이 가능한 X선 CT 시스템 개발 I - X선 촬영법을 이용한 목재의 밀도 측정 -

  • Kim, Kwang-Mo (Timber Engineering Lab., Major in Environmental Materials Science, Department of Forest Science, Seoul National University) ;
  • Lee, Sang-Joon (Timber Engineering Lab., Major in Environmental Materials Science, Department of Forest Science, Seoul National University) ;
  • Lee, Jun-Jae (Timber Engineering Lab., Major in Environmental Materials Science, Department of Forest Science, Seoul National University)
  • 김광모 (서울대학교 산림과학부 환경재료과학전공 목구조연구실) ;
  • 이상준 (서울대학교 산림과학부 환경재료과학전공 목구조연구실) ;
  • 이전제 (서울대학교 산림과학부 환경재료과학전공 목구조연구실)
  • Received : 2005.08.08
  • Accepted : 2005.12.05
  • Published : 2006.01.25
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Abstract

ln order to manage efficiently many ancient wooden buildings, which have been preserved as cultural properties in Korea, the internal state of wood members should be evaluated exactly and periodically by a NDE (non-destructive evaluation) method. A research project was planned to develop an X-ray CT (computed tomography) system as a NDE method for wood, which could be easily applied in field. This paper includes the first part of this project. First of all, to establish a measuring procedure of wood density using X-ray radiography, the correlation between X-ray intensity and the film brightness was evaluated. Also, initial X-ray intensity was quantified with various radiate conditions controlled by the tube voltage and tube current. And then, the effects of density, annual ring angle, and thickness on the mass attenuation coefficient of wood were examined. Finally, Beer's law was modified with the above results and adopted to calculate the density of wood. As a result of this study, the measuring procedure of wood density was established using a portable soft X-ray device and this procedure was verified with some small wood specimens. This results will he used valuably for the following researches to develop a portable X-ray CT system.

국내에서 문화재로 지정되어 관리되고 있는 많은 목조 고건축물들의 효과적인 보존 및 관리를 위해서는 목재의 내부 상태를 정확하게 평가할 수 있든 비파괴 검사법이 요구된다. 따라서 본 연구에서는 현장에서 적용 가능한 X선 CT 시스템을 개발하기 위한 연구의 일환으로, 먼저 휴대형 soft-X선 촬영 장치를 사용한 목재의 밀도측정 방법을 확립하고 그 적용 가능성을 확인하고자 하였다. 먼서 측정방법을 확립하기 위하여 X선 강도와 필름명도 사이의 상관관계를 분석하였으며, 또한 관전류와 관전압의 변화에 따른 X선 초기강도의 변화를 확인하여 정량화 하였다. 다음으로 목재의 밀도와 연륜각, 두께가 질량감쇠계수에 미치는 영향을 확인하고, 목재의 침량감쇠계수를 결정하여 Beer의 법칙에 적용함으로써 X선 측정결과로부터 목재의 밀도를 계산할 수 있는 식을 제시하였다. 마지막으로 X선 촬영법을 통해 측정한 밀도를 기존의 치수법에 의한 측정결과와 비교함으로써 앞에서 결정된 밀도측정 방법의 작용 가능성을 확인할 수 있었다. 이상의 결과는 앞으로 개발하고자 하는 X선 CT 시스템에서 입력값으로 요구되는 밀도를 측정하는 방법을 확립하는데 있어서 효과적으로 활용될 수 있을 것으로 기대된다.

Keywords

Acknowledgement

Supported by : 농림부

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