低应变率对云南松顺纹抗压强度的影响  

Effect of Low Strain Rate on the Compressive Strength along the Grain of Pinus yunnanensis

作　　者：刘建辉 徐国林[1] 柏亚双[1] 耿稳清 林宇杰 Liu Jianhui;Xu Guolin;Bai Yashuang;Geng Wenqing;Lin Yujie(Southwest Forestry University,Kunming,650224,P.R.China)

机构地区：[1]西南林业大学,昆明650224

出　　处：《东北林业大学学报》2023年第12期115-119,共5页Journal of Northeast Forestry University

基　　金：国家自然科学基金项目(52268051)。

摘　　要：木材的力学性能会因外荷载引起的应变率不同而发生改变,为探究地震荷载作用时,云南松(Pinus yunnanensis)木材顺纹抗压强度和峰值位移在1×10-4、1×10^(-3)、5×10^(-3)、1×10-2s^(-1)这4种应变率的变化规律,利用尺寸为30 mm×30 mm×40 mm试件开展轴压试验;利用试验数据获得云南松顺纹抗压强度动力提高系数表达式;使用能量演化方法解释木材应变率效应。结果表明:随着应变率增大,云南松木材试件斜向剪切破坏、劈裂破坏越明显;云南松木材的顺纹抗压强度随应变率增大而增大;云南松木材试件的峰值位移受应变率影响发生改变,但峰值位移随应变率变化相对离散,不存在明显线性关系;能量演化方法可用于解释木材的应变率效应,利用该方法计算出的不同应变率的压力做功,也随应变率增大而增大;使用线性拟合方法给出了云南松顺纹抗压强度动力提高系数表达式,根据该系数可实现应变率不同时,云南松木材测试抗压强度的调整。Under different strain rates caused by external loads,the wood presents different mechanical properties.The compressive strength and peak displacement of Pinus yunnanensis wood at four strain rates of 1×10-4,1×10^(-3),5×10^(-3)and 1×10-2 s^(-1)are tested to explore the mechanic character variation law under earthquake loads.The axial compression test was carried out on specimens of P.yunnanensis with dimensions of 30 mm×30 mm×40 mm.With the test data,the expression of the dynamic improvement coefficient of compressive strength of Yunnan pine grain was obtained.The energy evolution method was used to explain the strain rate effect of wood.The results showed that with the increase of strain rate,the inclined shear failure and splitting failure of P.yunnanensis wood specimen become more obvious.The compressive strength of P.yunnanensis increased with the increase in strain rate.The peak displacement of P.yunnanensis wood specimens was changed by strain rate,but the peak displacement was relatively discrete with strain rate,and there was no obvious linear relationship.The energy evolution method can be used to explain the strain rate effect of wood.The work of pressure calculated by this method also increases with the increase of strain rate.The linear fitting method was used to give the expression of the dynamic improvement coefficient of compressive strength of P.yunnanensis.The compressive test strength of P.yunnanensis wood can be adjusted at different strain rates by using this coefficient.

关 键 词：应变率 抗压强度 峰值位移 云南松 

分 类 号：S781.2[农业科学—木材科学与技术] TU366.2[农业科学—林学]