人工林杨木材性对单板层积材强度的贡献率

CONTRIBUTIVITY OF PLANTATION POPLAR WOOD PROPERTIES TO LVL STRENGTH

本文提出了衡量单板层积材强度中实木材性所占份额的贡献率概念，以揭示实木材性对单板层积材强度的贡献程度。以人工林杨木为对象，研究了实木材性对单板层积材强度的贡献率。结果表明，实木材性好或单板层积材中的单板较厚时，贡献率较高。材性较优的６９杨和材性居中的７２杨、材性较差的６３杨３个无性系杨木的平均贡献率分别为７４３４％、６７４８％、６４７２％，厚度为３５６５ｍｍ、２６１４ｍｍ、１５４５ｍｍ单板组配的单板层积材中的平均贡献率分别为７４００％、６７４８％和５８０６％。研究的６项强度性能中，杨木实木材性对抗剪强度、弹性模量和冲击韧性的贡献率较高，约为８０％。

The concept of contributivity was put forward in this paper. It can be used to measure the contribution ratio of solid wood properties to LVL strength. The contributivity of 3 poplar clones from plantation was studied and the results shows that poplar with good solid wood properties or LVL with thick veneers gives high contributivity. The average contributivity of good poplar 69, poplar 72 and poor poplar 63 is 74 34%, 67 48% and 64 72%, respectively. When LVL is assembled with the veneers of 3 565mm, 2 614mm and 1 545mm in thickness, the average contributivity is 74 00%, 67 48% and 58 06%, respectively. In addition, the contributivity of shear strength, modulus of elasticity and toughness is approximated to 80%, which is higher than that of the other 3 properties.