應力波檢測木材縱向接合之彈性係數

Stress Wave Detecting the MOE of Longitudinal Joint of Wood

陳載永(Tsai-Yung Chen) ； 陳合進(Ho-Chin Chen)

《林產工業》 16卷1期 (1997/03) Pp. 8-21

https://doi.org/10.6561/FPI.1997.16(1).2

摘要

本研究主要在分析3種應力波非破壞性測定法，用於檢測巴杜柳桉、紅櫟木、花旗松和美國西部鐵杉等材料，製作的4種縱向材之彈性係數，並比較其與傳統破壞性檢測接合強度之相關性。試材經接合後波速會明顯增快，而振動頻率則沒有一定趨勢。在靜曲破壞強度試驗時，樹種中以巴杜柳桉最大，花旗松最小；接合法則以指接的強度最大對接最小。至於MOEd與MOE之相關性，經簡單直線迴歸分析結果，是樹種中以花旗松的相關性最高，其r^2值在0.85以上，而美國西部鐵杉的相關性最低，r^2值在0.50以下。

關鍵字

非破壞性測定 ； 應力波 ； 靜曲彈性係數 ； 動彈性係數 ； 最大彎矩

並列摘要

The stress-wave nondestructive test (NDT) method was applied in this research to test the MOE for four kinds of longitudinal joint of Selangan batu (Shorea spp.), Red oak (Quercus spp.), Douglas fir (Pseudotsuga menzieii Frano.)and American hemlock (Tsuga heterophylla Sorg.) , and was tried to predict the joiont defect. The relationship of joint strength predicted by NDT and that tested by traditional destructive metnhod was correlated. For the longitudinal joint, the wave velocity of all samples would become obviously faster after jointed, but no constant tendency in vibration frequency was observed. Bending test showed that the MOR among the wood species, Selangan batu had higher strength value, and Douglas fir was the lowest. Among the hoint methods, the best one was finer-joint, and the worst one was butt hoint. The relationship between MOEd and MOE was tested by linear regression analysis , the coefficients of correlation determination showed that the highest value was Douglas fir (r^2＞0.85), and the lowest was American hemlock (r^2＞0.50).

並列關鍵字

Non-destructive testing ； stress-wave ； MOE ； MOR ； bending moment