高应变率加载自由水对全饱和木材原料解离强度的影响  

Effect of Free Water on Dissociation Strength of Fully Saturated Wood Raw Materials Based on High Strain Rate Loading

作　　者：许威[1] 曹军[1] 花军[1] 陈光伟[1] Xu Wei;Cao Jun;Hua Jun;Chen Guangwei(Northeast Forestry University,Harbin 150040,P.R.China)

机构地区：[1]东北林业大学,哈尔滨150040

出　　处：《东北林业大学学报》2023年第12期125-129,共5页Journal of Northeast Forestry University

基　　金：教育部高等学校博士学科点专项科研基金(博导类)项目(20130062110005);黑龙江省普通本科高等学校青年创新人才培养计划项目(UNPYSCT-2020216)。

摘　　要：以全饱和杨木为试材,加载方向为径向、弦向、轴向,进行了低应变率(0.001 s^(-1))、高应变率(400、700、1000 s^(-1))的加载试验,测试了全饱和木材的抗压强度,分析了全饱和木材试件内部的自由水对木材抗压强度的影响。结果表明:全饱和木材试件的解离程度随应变率的增加而增大,抗压强度具有显著的应变率效应;试件内部自由水流动的雷诺数为1127.60,流态为层流,自由水的水击冲击产生的最大局部压强分别约为径向、弦向抗压强度的2.16、2.76倍,自由水对试件力学性能的减弱和增强作用主要受应变率影响,当应变率小于临界应变率时,自由水主要起增强木材强度的作用;当应变率大于临界应变率时,自由水主要起减弱木材强度的作用。Using fully saturated poplar wood as test material,the loading tests of low strain rate(0.001 s^(-1))and high strain rate(400,700 and 1000 s^(-1))were carried out with radial,tangential and axial loading directions.The compressive strength of fully saturated wood was tested,and the effect of free water in fully saturated wood on wood compressive strength was analyzed.The results show that the dissociation degree of fully saturated wood specimen increases with the increase of strain rate,and the compressive strength has a significant strain rate effect.The Reynolds number of free water flow in the specimen is 1127.60 and the flow pattern is laminar flow.The maximum local pressure generated by the water hammer impact of free water is about 2.16 times and 2.76 times of the radial and tangential compressive strength,respectively.The weakening and strengthening effect of free water on the mechanical properties of specimens is mainly affected by strain rate.When the strain rate is less than the critical strain rate,free water mainly enhances wood strength and when the strain rate is greater than the critical strain rate,free water mainly weakens the wood strength.

关 键 词：木材 应变率 全饱和 自由水 解离强度 

分 类 号：S781[农业科学—木材科学与技术]