Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/65728
標題: Determining MOE of Wood by Stress Wave-Nondestructive Testing Method.
應力波非破壞測定法檢測木材彈性係數
作者: 鍾建有
Chung, Chien-Yo
關鍵字: Nondestructive-testing;非破壞性測定;MOE;MOEd;MOR;靜曲彈性係數;動彈性係數;靜曲破壞係數
出版社: 森林學系
摘要: 
本研究乃針對木材加工過程中的外來因素進行分析,並探討三種應力波非
破壞測定法,用於檢測實木與木質板材靜曲彈性係數時之相關性。以應力
波非破壞性測定法檢測木質板材方向性差異時,合板於板寬方向之應力波
傳遞速度、縱向振動頻率與靜曲彈性係數較高。定向粒片板則以板長方向
較高,而中密度纖維板與粒片板之差異較不明顯。當試材於相同長度與厚
度,寬度變化對波速之影響小;寬度為 2.4cm之木條,其波速只比寬度
為 40 cm 之板材快約1 ∼ 2 %;不同試材支撐方式並不會改變波速,但
是會影響縱向振動頻率;打音頻譜分析系統以中心點支撐方式測得之相關
性較高;振動頻率測定器則以十字型或中心點支撐方式相關性較高。荷重
試驗時試材有無承受靜曲荷重,並不會影響波速,然而振動頻率就會明顯
改變。若於試材上製作人造孔洞時,波速與縱向振動頻率都會因孔徑加大
與數量增加而降低 , 三種應力波非破壞測定法檢測木材靜曲彈性係數時
,以振動頻率測定器檢測花旗松之結果最好,其縱向振動頻率與靜曲彈性
係數經迴歸分析,r 平方= 0.98 ;而柳桉材幾乎無相關性;當儀器用於
兩種木質板材檢測時,r 平方也在 0.65 以上。

This study is to find out how extra factors affect the wood
products during processing period, and to search the
relationship between MOE derived from applying three stress
wave nondestructive testing instruments. According to the
inspection of the anisotropic characteristics of wood based
panels,width direction of plywood showing the higher value in
stress wave velocity,longitudinal vibration frequency and MOE.
For OSB the long-side direction gained the higher value in wave
velocity,longitudinal vibration frequency and MOE.For MDF and
particleboard are not apparent.The wave velocity varies not
significant in width,while the length and thickness of board
are constant, the wave velocity of stick in width 2.4 cm, was
1-2% faster than which in width is 40 cm.The wave velocity won''
t be affected by different supporting ways, but longitudinal
vibration frequency for tap tone analysis system,the middle
point supporting way showed the better relationship between
longitudinal vibration frequency and MOE.For vibration
frequency tester,the supporting method by the crucifix and the
center point way obtained the best results.The sample with or
without static loading has no affect on the wave velocity.If
the sample is holed artificially,the wave velocity as well as
longitudinal vibration frequency will decrease with increasing
diameter and number of holes.Applying three instruments stress
wave nondestructive testing to indirectly determine MOE, showed
that douglas-fir tested with vibration frequency tester gained
better result,it''s (r square) between longitudinal vibration
frequency and MOE is 0.98.Lauan gained the worst for there is
no relationship between longitudinal vibration frequency and
MOE.Testing in MDF and particleboard,the (r square) are larger
than 0.65.
URI: http://hdl.handle.net/11455/65728
Appears in Collections:森林學系

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