原木横截面应力波传播时间等值线绘制及影响因素分析  

Construction of Stress Wave Time Isolines on Log Cross Section and Analysis of Its Effect Factors

作　　者：徐华东[1] 徐国祺[1] 王立海[1] 杨学春[1] 

机构地区：[1]东北林业大学工程技术学院,哈尔滨150040

出　　处：《林业科学》2014年第4期95-100,共6页Scientia Silvae Sinicae

基　　金：国家自然科学基金(31300474);中央高校基本科研专项资金(DL12BB18);国家林业公益性行业科研专项经费重大项目(20110 4007)

摘　　要：以大青杨原木为试验材料,在原木样本横截面布置离散网格式测点,采用应力波方法,测试横截面内应力波传播时间(SWT),采用Matlab模拟SWT等值线,分析温度和空洞缺陷对SWT等值线的影响。结果表明:应力波在完好原木横截面以圆弧形曲线传播,沿径向传播最快,而沿弦向传播则较慢;空洞和温度对SWT等值线均有显著影响;低温原木中应力波传播更快;与完好样本相比,含空洞原木SWT等值线形状有较大差异;空洞改变了应力波传播路径,促使SWT增加;传播到空洞后面区域的SWT数值与空洞直径正相关,在木材径向这一趋势更显著。The change of stress wave time（ SWT） or velocity in the cross section of standing trees is usually used for the evaluation of its internal decay. The velocity change is closely related with the transmitting path of stress wave,so the study of stress wave transmitting path is the basis of inner decay testing of trees and logs. Stress wave method was employed to test Populus ussuriensis log specimen for obtaining SWT data,which were then used to simulate the SWT isolines by Matlab. The effects of temperature and cavity defect on the SWT isolines on the cross section were also discussed. The results showed that the shape of SWT isoline was arc on the cross section of intact log,which transmited fast in longitudinal and slow in tangential. The velocity of stress wave in log at cold temperature was higher than that in room temperature. The shapes of SWT isolines in defective log were significantly different with that in intact log. Cavity changed the transmitting path of stress wave and enlarges SWT value. When stress wave propagates to the area behind the cavity,SWT increased as the diameter of cavity increases,which was very significant in longitudinal direction.

关 键 词：应力波传播时间 原木 无损检测 等值线 

分 类 号：S781.51[农业科学—木材科学与技术]