熱處理柳杉製材之抗灣性能評估

Evaluating the Bending Properties of Heat-treated Japanese Cedar Lumber

張豐丞(Feng-Cheng Chang) ； 張夆榕(Feng-Rong-Chang) ； 趙偉成(Wei-Cheng Chao) ； 楊德新(Te-Hsin Yang)

《林產工業》 34卷2期 (2015/06) Pp. 59-67

https://doi.org/10.6561/FPI.2015.34(2).2

摘要

本研究探討國產35年生柳杉製材經熱處理後之抗彎機械性質，並經機械分等後，評估熱處理柳杉機械分等材之特徵值與容許應力值，以做為未來熱處理柳杉製材應用之參考。結果顯示試材經190°C熱處理2h後，柳杉製材之密度與抗彎強度有下降之趨勢，而抗彎彈性模數則略有提升。另外，而熱處理柳杉製材經機械分等後主要集中在E90級，其次為E70級。此外，以超音波法、應力波法、打音法等三種非破壞試驗法評估熱處理柳杉製材結果指出，3種動彈性模數與抗彎彈性模數之相關係數為0.79-0.85，其中以打音動彈性模數與抗彎彈性模數之相關性較佳。熱處理柳杉製材經機械分等後，其E70級以上等級者之結構設計值高於整體未分等時所計算之容許值，顯示熱處理柳杉製材，經機械分等後較可有效掌握材料性質，可作為未來應用於結構設計之參考。

關鍵字

熱處理材 ； 柳杉 ； 抗彎性質

並列摘要

In this study, the flexural properties of 35-yr domestic plantation Japanese cedar lumber heat-treated with 190°C for 2-hour were investigated, and the parametric tolerance limit and allowable stress values of heat-treated Japanese cedar were evaluated after mechanical grading. The experimental results showed that the density and flexural strength of Japanese cedar decreased after heat treatment; however, the values of modulus of elasticity (MOE) slightly increased. Furthermore, after grading in accordance with MOE, the grades of heat-treated Japanese cedar were sorted mainly in E90, followed by E70. Moreover, by using ultrasonic wave, stress wave and tap tone methods to measure and calculate dynamic modulus of elasticity (DMOE) values of Japanese cedar would result in the correlation coefficient of 0.79-0.85, and the results of tap tone method showed the highest correlation coefficient. In addition, by grading lumber in accordance with MOE values, the heat-treated Japanese cedar of E90 or above levels would have higher structural design values, comparing to ungraded heat-treated Japanese cedar. Therefore, E70-grading could effectively grasp the properties of heat-treated Japanese cedar plantation wood, and that could be used as the reference for further applications of heat-treated Japanese cedar wood on timber structures.

並列關鍵字

Heat-treated wood ； Japanese cedar ； Bending property