木材之動力學與音響學特性之研究（III）－膠合對木材之動彈性係數與內部磨擦之影響

Studies on the Dynamic and Acoustic Behaviors of Wood (III) the Effect of Gluing on the Dynamic Modulus of Elasticity arid Internal Friction of Wood

王松永(Song-Yung Wang) ； 卓志隆(Jyh- Long Jwo)

《林產工業》 4卷3期 (1985/09) Pp. 2-26

https://doi.org/10.6561/FPI.1985.4(3).1

摘要

本研究目的是利用共振頻率法及超音設法以探討膠合對木材動彈性係數與內部摩擦之影響。並究明其當作音響材料時的特性指標。所得結果如次：（1）集成材之動彈性係數均會隨其K_4（膠合層影響特性係數），PGL（膠合層厚率），ρ（集成材密度）之增加而垂直線狀增犬。其關係可以實驗式(23)~(30)及(34)~(42)表示。（2）集成材之動彈性係數E_D（由超音設法所得值）會較E'_H或E'_V值（共振頻率法所得值）大25%~35%。（3）集成材之內部摩擦Q^(-1)變動性較大。在膠合層少於5層時，RF group之Q_H^(-1)值會較PVAc group為大，但當膠合層多於7層時，則相反。（4）集成材之動彈性係數與比動彈性係數（E'_H/ρ，E'_V/ρ,E_D/ρ）有RF group＞UF group＞PVAc group之趨勢。（5）集成材之音波抵抗（w）會隨其K_4，或ρ增加而呈直線狀增大，其關係可以實驗式（55）～（72）表示。（6）集成材之音投放射衰減率（V_T或K）會隨其K_4，ρ或W增加而呈直線狀減低，其關係可以實驗式（77）～（101）及（102）～（113）表示。（7）當集成材由其比動彈性係數考慮當作運動器材使用峙，其希望是使用RF膠，且含有較多膠合層者。但如由其音波抵抗及音波放射衰減率，考慮當作音響材料時，其是希望使用PVAc或UF膠，且含有較少之膠合層者。

關鍵字

膠合 ； 集成材 ； 共振頻率法 ； 超音波法 ； 動彈性係數 ； 內部摩擦

並列摘要

T he purpose of this study was to investigate the effect of gluing on the dynamic modulus of easticity and internal friction of woods by using the flexural resonance vibration method and ultrasonic wave method and then discuss its characteristics as a musical instrument. The experimental results are summarized as follows: (1) The dynamic modulus of elasticity of laminated glulam increased linearly with increasing K_4 (influential coefficient of glue line), PGL (percentage of glue line) and ρ (density of laminated glulam). The relationships among them were shown by experimental formulas (23) to (20) and (34) to (42). (2) The values of dynamic modulus of elasticity E_D (calculated from ultrasonic wave method) were 25% to 35% greater than those of E'_H or E'_V (calculated from flexural resonance vibration method). (3) The internal friction of laminated glulam showed more variation. The values of internal friction of RF group were larger than those of PVAc group when the number of glue line was less than 5. However, the opposite relationship holds, when the number of glue line was more than 7. (4) The dynamic modulus of elasticity and ration of dynamic modulus of elasticity (E'_H/ρ, E'_v/ρ, E_D/ρ) were had the following order: RF group＞UF group＞PVAc group. (5) The sound wave resistance (W) of laminated glulam increased linearly with increasing K_4 or ρ, Their relationships were shown by the experimental formulas (55) to (72). (6) The damping of sound radiation (V_T or K) of laminated glulam decreased linearly with increasing K_4, ρ or W, Their relationships were shown by the experimental formulas (77) to (101) and (102) to (113). (7) When the laminated glulam were used as a sports instrument by its ratio dynamic modulus of elasticity, it was better to use RF adhesives and had more glue lines, However, When the laminated glalam were used as a musical instrument by its sound wave resistance and damping of sound radiation, it was better to use PVAc adhesives or UF adhesives and had less glue lines.

並列關鍵字

Gluing ； Laminated glulam ； Resonance vibration method ； Ultrasonic wave method ； Dynamic modulus of elasticity ； Internal friction