水分对棕榈藤材弯曲性能的影响

Influence of moisture content on the bending properties of rattan cane

选取国产单叶省藤材和黄藤材为研究对象,分析了水分对棕榈藤材弯曲弹性模量、弯曲强度、比例极限应力、破坏应力(极值应力)、比例极限应变、破坏应变和韧性系数等性能指标的影响。结果表明,藤材弯曲性能与其水分含量密切相关;藤材抗弯弹性模量和抗弯强度,在纤维饱和点以下,随水分增多明显降低,及至纤维饱和点后趋于稳定;藤材比例极限应力受水分影响较小,藤材极值应力在纤维饱和点前随含水率提高显著降低,至纤维饱和点后趋于稳定;藤材的比例极限应变随其水分含量不同无明显差异,藤材破坏应变随其水分含量增多显著增大;黄藤材比单叶省藤材材质更脆,其饱湿含水率和饱水含水率更大,韧性受水分影响也更显著;通过增大或封存藤材水分,能提高藤材弯曲性能,改善藤材脆性。

The bending elasticity modulus （MOE）, bending strength （MOR）, proportional limit stress and strain, failure stress and strain, and toughness coefficient of rattan canes under different moisture contents （MC） were determined to explore the influence of MC on the bending properties of Calamus simplicifolius and Dae- monorops margaritae rattan canes. Results showqd that cane bending properties were closely related to its MC. Below the fiber-saturation point （FSP）, the MOE and MOR declined significantly with increasing MC, thereafter the change was a little. The influence of MC on cane proportional limit stress was little, while the cane failure stress was great. Below the FSP, the failure stress reduced significantly with increasing MC, thereafter no obvious change was observed. In different MC, the proportional limit strain was relatively constant, but the failure defor- mation increased greatly with increasing MC. The influence of MC on the toughness index ofD. margaritae cane was much bigger than that of C. simplicifolius cane; the more brittle the rattan cane was, the more significant in- fluence was. It was suggested that increasing or fixing cane moisture could improve its bending performance and restrain its brittleness.