意杨木材弹性模量3种方法检测的比较

摘要

The two typical methods such as free beam vibration method and static three-point bending method in the paper were employed to verify the feasibility and reliability of the stress wave method for testing and evaluating the modulus of elasticity of Populus euramericana wood by measuring the modulus of elasticity values of a batch of P.euramericana lumbers.The confidence level, the accurate index and their correlation in three ways were studied comparatively and experimentally.The results showed that the modulus of elasticity values measured by the three methods had high correlations, the correlation coefficients were all greater than 0.8.And the confidence level and accurate index of dynamic modulus of elasticity measured by stress wave were the lowest.Then lumber grading was conducted based on the modulus of elasticity values obtained from stress wave tests, and it was proved that the percentage of GradeⅠproduct quality was 26.2%, GradeⅡproduct quality was 56.9%, and GradeⅢproduct quality was 16.9%, respectively.Hence, stress wave method can be used to measure the modulus of elasticity of sawn timber, and regarded as one of the methods for evaluating the quality and predicting mechanics behaviors of the wood.%为比较不同无损检测方法检测、评估意杨木材弹性模量的可行性和可靠性，分别采用应力波法、自由梁振动法和静态四点弯曲法实测一批苏北意杨锯材的弹性模量值，比较研究了3种方法下的意杨锯材弹性模量值的变异系数、准确指数及相关性。结果表明：3种方法测算的锯材弹性模量值间显著相关，相关系数均大于0．8，且三者中应力波法检测锯材的动态弹性模量值的变异系数和准确指数最小，依据原木应力波弹性模量对锯材进行分等，得到Ⅰ级品率为26．2％，Ⅱ级品率为56．9％，Ⅲ级品率为16．9％。可见，应力波法能够用于检测锯材弹性模量，并作为评定木材性质、预测其力学性能的方法，为中国木材行业锯材产品的最佳质量分等提供理论借鉴。