考虑应力影响的杉木力学性能微钻阻力检测

Micro-drilling resistance testing of fir mechanical properties under stress

在役木结构构件常处于受弯、受压等受力状态,常用微钻阻力法检测木材的试验研究,该法通常没有考虑实际受力状态对阻力值的影响。本文以直径15 cm、高度40 cm杉木试件作为研究对象,首先,通过对无应力状态下杉木试件的微钻阻力试验研究,获得微钻阻力值与木材密度、顺纹抗压强度、顺纹抗压弹性模量及抗弯强度之间的回归方程;然后,对处于压应力状态下的杉木试件进行微钻阻力试验,得到随着应力等级的提升,微钻阻力值呈上升趋势;最后,提出了考虑应力影响的杉木微钻阻力值修正系数及修正后的回归方程。

The in-service timber members were often under bending,compression and other stress states.Experimental studies on wood testing with the existing micro-drill resistance method were generally carried out without considering the impact of the actual stress state on the resistance value. In the paper,15 cm in diameter and 40 cm in height fir was chosen as the specimen. The regression equation between the micro-drill resistance value and wood density,compression strength parallel to grain,flexural strength and compressive elastic modulus of wood were obtained through the micro-drill resistance test under non-stress state. The micro-drill resistance test was conducted on the fir under compressive stress. Results showed that with the increasing of stress level,the micro-drill resistance value showed a rising trend. The correction coefficient of micro-drilling resistance value and the modified regression equation of fir with considering the influence of stress were proposed.