林业科学
林業科學
임업과학
SCIENTIA SILVAE SINICAE
2014年
4期
95-100
,共6页
徐华东%徐国祺%王立海%杨学春
徐華東%徐國祺%王立海%楊學春
서화동%서국기%왕립해%양학춘
应力波传播时间%原木%无损检测%等值线
應力波傳播時間%原木%無損檢測%等值線
응력파전파시간%원목%무손검측%등치선
stress wave time ( SWT)%log%nondestructive testing%isolines
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。
以大青楊原木為試驗材料,在原木樣本橫截麵佈置離散網格式測點,採用應力波方法,測試橫截麵內應力波傳播時間( SWT),採用Matlab模擬SWT等值線,分析溫度和空洞缺陷對SWT等值線的影響。結果錶明:應力波在完好原木橫截麵以圓弧形麯線傳播,沿徑嚮傳播最快,而沿絃嚮傳播則較慢;空洞和溫度對 SWT 等值線均有顯著影響;低溫原木中應力波傳播更快;與完好樣本相比,含空洞原木 SWT 等值線形狀有較大差異;空洞改變瞭應力波傳播路徑,促使 SWT增加;傳播到空洞後麵區域的 SWT 數值與空洞直徑正相關,在木材徑嚮這一趨勢更顯著。
이대청양원목위시험재료,재원목양본횡절면포치리산망격식측점,채용응력파방법,측시횡절면내응력파전파시간( SWT),채용Matlab모의SWT등치선,분석온도화공동결함대SWT등치선적영향。결과표명:응력파재완호원목횡절면이원호형곡선전파,연경향전파최쾌,이연현향전파칙교만;공동화온도대 SWT 등치선균유현저영향;저온원목중응력파전파경쾌;여완호양본상비,함공동원목 SWT 등치선형상유교대차이;공동개변료응력파전파로경,촉사 SWT증가;전파도공동후면구역적 SWT 수치여공동직경정상관,재목재경향저일추세경현저。
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.