The Practice of Bending Deflection using Non-destructive MOE of Glulam

비파괴 탄성계수를 이용한 집성재의 휨변형 예측

  • Park, Jun-Chul (Department of Wood Science & Engineering, College of Forest & Environmental Sciences, Kangwon National University) ;
  • Hong, Soon-Il (Department of Wood Science & Engineering, College of Forest & Environmental Sciences, Kangwon National University)
  • 박준철 (강원대학교 산림환경과학대학 임산공학과) ;
  • 홍순일 (강원대학교 산림환경과학대학 임산공학과)
  • Received : 2008.05.27
  • Accepted : 2008.11.12
  • Published : 2009.01.25

Abstract

In the glulam beam deflection it is necessary to check the reliability of theory formula, because of wood anisotropy and wood qualities (knot, slop of grain). In this experiment, when bending stress occurred on glulam, practice deflection of glulam measuring with AICON DPA-Pro 3D system were compared with prediction deflection calculated as substituting MOE through non-destructive testing and static MOE through bending test in differential equation of deflection curve. MOE using ultrasonic wave tester of laminae, MOE using natural frequencies of longitudinal vibrations ($E_{cu}$, $E_{cf}$), MOE using ultrasonic wave tester of glulam ($E_{gu}$) and MOE using natural frequencies of longitudinal vibrations ($E_{gf}$) were substituted in this experiment. When practice deflection measured by 3D system was compared with prediction deflection calculated with differential equation of deflection curve, within proportional limit the ratio of practice deflection and prediction deflection was similar as 1.12 and 1.14, respectively. Deflection using ultrasonic wave tester was 0.89 and 0.95, Deflection using natural frequencies of longitudinal vibrations was 1.07 and 1.10. The results showed that prediction deflection calculated by substituting using non-destructive MOE of glulam having anisotropy in differential equation of deflection curve was agreed well with practice deflection.

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