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该文以经过120 d、温度90℃条件下窑干干燥处理的56根日本柳杉人工林结构材(110 mm×55 mm×2 500 mm)作为测试试件,介绍了一种利用激光测距系统测量顺纹抗拉弹性模量的方法.首先将试件含水率调至15%,在抗拉试验开始前采用纵向基频振动方法(FFT)得到试件的动态弹性模量(Efr),再利用由激光测距仪、数据采集器和计算机处理系统组成的激光测距系统,测定了顺纹抗拉弹性模量(Et),最后破坏试件完成顺纹抗拉强度(σt)的测定.对Efr、Et和tσ相互关系的比较分析表明,Et的平均值比FFT方法得到的Efr的平均值小7.8%(0.63GPa);Et与Efr具有很好的相关性,相关系数R为0.971,在0.001水平上呈显著相关;Et和σt的相关系数R为0.727,也在0.001水平上呈显著相关.足尺试件的顺纹抗拉测试结果表明,激光测距方法可以准确地测量结构材在顺纹受拉时发生的拉伸变形,从而得到可靠的抗拉弹性模量试验结果.
In this paper, 56 Japanese cedar artificial forest structures (110 mm × 55 mm × 2 500 mm) treated by kiln drying at 120 ℃ and 90 ℃ were used as test specimens. The system measures the modulus of parallel tensile elastic modulus by first adjusting the moisture content of the specimen to 15% and obtaining the dynamic modulus of elasticity (Efr) of the specimen by longitudinal fundamental frequency vibration (FFT) before the start of the tensile test, Then the laser ranging system composed of laser range finder, data acquisition and computer processing system was used to measure the elastic modulus (Et) of the parallelogram and finally to determine the parallelogram tensile strength (σt) . A comparative analysis of the correlations between Efr, Et and tσ showed that the average Et was 7.8% (0.63 GPa) less than the average of the Efr obtained from the FFT method. Et and Efr had good correlation with a correlation coefficient R of 0.971 , And the correlation coefficient between Et and σt was 0.727, which was also significantly correlated at the level of 0.001. The results of the parallel grading test of full-scale specimens showed that the laser ranging method can accurately measure the structure Tensile deformation occurs when the material is pulled in parallel to obtain a reliable tensile modulus of elasticity test result.