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題名 | 不同栽植距離柳杉木材之動彈性係數及靜曲性質之影響因子探討=Influential Factor of Dynamic Modulus of Elasticity and Bending Properties of Japanese Cedar Grown in Different Plantation Spacing Sites |
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作者 | 王松永; 林淑華; Wang, Song-yung; Lin, Shu-hua; |
期刊 | 中華林學季刊 |
出版日期 | 19970300 |
卷期 | 30:1=116 1997.03[民86.03] |
頁次 | 頁3-13 |
分類號 | 436.257 |
語文 | chi |
關鍵詞 | 柳杉造林木; 栽植距離; 強度在徑向及軸向變異性; 強度影響因子; 靜曲破壞型態; Japanese cedar plantation timber; Plantation spacing; Variation of strength in the radial and axial direction; Influential factor of strength; Fracture pattern in bending; |
中文摘要 | 本研究係探討五種栽植距離之41年生柳杉造林木,在單株內強度變異性,各項強度之影響因子,及靜曲破壞型態。本實驗各板材(總數569片)先使用Metriguard Model 340 Transverse Vibration Tester求得動彈性係數(Ed)後,再由三分點載重靜曲方法求得各板材之破壞係數(MOR)及靜曲彈性係數(MOE),最後依靜曲破壞面判斷其靜曲破壞型態。試驗結果可歸納於次:1. 各項強度(MRO,MOE及Ed)值會由髓心向樹幹外側增加,至距髓心6-12 cm附近維持最大值,其後會向樹皮側減低。而各項強度值會由樹基部向樹梢側增大。2. 各項強度值均顯著的受到栽植距離,距髓心距離、密度及三分點載重之兩載重間14 cm長木材之最大節徑比等四項因子的影響外,MOR又會受木理傾斜角、Ed又會受樹幹高度之影響。3. 各項強度值均會顯著的受到三分點載重之兩載重點間14 cm長木材所出現之最大節徑比(Case 1)拉伸面之集中節徑比(case 2),所有集中節徑比(case 3),及三分點載重整個跨距長木材之所有節徑比(Case 4)等之影響,但以Case 1之相關係數最高。4. 柳杉板材之靜曲破壞型式有四個類型,即節點破壞型態佔38.6%,碎裂拉伸破壞佔26.6%,斜走木理破壞佔19.7%,及單純拉伸破壞佔15.1%。 |
英文摘要 | The main purpose of this study was to investigate the influential factors of dynamic modulus of elasticity and bending properties and the fracture pattern in bending test of 41-year old Japanese cedar grown in five different plantation spacing sites. In this study, Metriguard Model 340 Transverse Vibration Tester was used to measure the dynamic modulus of elasticity (Ed) values of a total of 569 plank specimens. then their modulus of rupture (MOR) and modulus of elasticity (MOE) were measured by using the third-point bending method, finally the fracture pattern in bending were evaluated by their bending fractural planes. The experimental results are summarized as follows: 1.In the radial direction, the strength values (MPR, MOE and Ed) increased from the pith outward, and reached the maximum values at the position around 3-12 cm from the pith, and then decreased toweards the bark. While in the axial direction, the strength values (MOR, MOE and Ed) of trunk apex showed larger values than those of stump base. 2.The strength valuse (MOR, MOE and Ed) were significantly affcted by four factors including plantation spacing, distance from the pith, density and maximum knot diameter ratio between two loading points (14cm) of a specimens under a third-pint bending test. Moreover, MOR value was affected by the grain angle of specimen, and Ed value was affected by trunk height. 3.The strength valuse (MOR, MOE and Ed) were significantly affected by the maximum knot diameter ratio between two loading points (14cm) of a specimen (Case 1), concentrated knot diameter ratio between two loading pints (14cm) on the tensile side of a pecimen (Case 2), total concentrated knot diameter ratio between two loading points (14cm) on a pecimen (Case 3), and total concentrated knot diameter ratio between two supporting points (42cm) of a specimen (Case 4) under a third-point bending test, However, the highest coefficient of correlation occurred in Case 1. 4.The fracture pattern in bending of Japanese cedar plank specimens showed four types, namely 38.6% for knot fracture type, 26.6% for splinter tension fracutre type, 19.7% for cross grain fracture type and 15.1% for single tension fracture type. |
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