小径级竹材抗弯性能测试方法

探究小径级竹材（胸高直径50 mm以下）的抗弯性能实验方法，充分发掘小径级竹材的性能，为小径级竹材的材性研究和工业加工等提供技术支撑，以扩大小径级竹材的用途，提高其利用价值。实验以箬竹、早园竹、苦竹、水竹和笔竿竹5种小径级竹材为研究对象，利用三点弯曲法与四点弯曲法分别测定了不同长径比（试件长度与其直径之比）试样的抗弯弹性模量和抗弯强度，以测试数据的标准差、标准误差和变异系数为评价依据，分析不同长径比的试样和加压弯曲方式对实验结果的影响。结果表明：就加压方式而言，当测试抗弯弹性模量时，三点加压弯曲法优于四点加压弯曲法；就试样长径比而言，长径比为12的试件更适于测试小径级竹材的抗弯弹性模量和抗弯强度。因此，当测试小径级竹材抗弯性能时，宜采用三点加压弯曲方式、长径比为12的试样并按照一定的流程进行操作。

Test Method of Bending Properties for Small Diameter Bamboo

The experimental method for bending properties of small diameter bamboo (DBH of less than 50 mm) is discussed to fully understand the properties of small diameter bamboo, so as to provide technical support for the research on the properties and industrial processing of small diameter bamboo, which will expand the use of small diameter bamboo and improve its utilization value. The experiments select small diameter bamboo of Indocalamus tessellatus, Phyllostachys propinqua, Pleioblastus amarus, Ph. heteroclada and Pseudosasa guanxianensis to measure the modulus of elasticity and the bending strength of the specimens with different length diameter ratio (the ratio of the specimen length and diameter) using three-point bending method and four-point bending method, respectively. Based on the standard deviation, standard error and coefficient of variation of the test data, the influence of different length diameter ratio and compression bending mode on the experimental results is analyzed. The results show that the three-point compression bending method is better than the four-point compression bending method when testing the modulus of elasticity. As far as the length-diameter ratio is concerned, the ratio of 12 is more suitable for testing the modulus of elasticity and bending strength of small diameter bamboo. Therefore, when testing the flexural performance of small diameter bamboo, it is advisable to use the three-point bending method and the specimen with a length-diameter ratio of 12 and operate the method according to a certain process.