Strength grading on the basis of high resolution laser scanning and dynamic excitation: a full scale investigation of performance

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• 作者：Anders Olsson ; Jan Oscarsson
• 刊名：European Journal of Wood and Wood Products
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：75
• 期：1
• 页码：17-31
• 全文大小：2655KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Wood Science & Technology; Ceramics, Glass, Composites, Natural Materials; Operating Procedures, Materials Treatment;
• 出版者：Springer Berlin Heidelberg
• ISSN：1436-736X
• 卷排序：75

文摘

Effective utilization of structural timber requires grading and indicating properties (IPs) that are able to predict strength with high accuracy and machines that are able to measure the underlying board properties at a speed that corresponds to the production speed of sawmills. The aim of this research is to assess the performance of a new machine strength grading method/procedure which was recently approved for the European market and to compare the performance of it with the performance of other available techniques. The novel method is based on laser scanning utilizing the tracheid effect, in combination with data from dynamic excitation and weighing. Applied indicating properties are defined in detail and results presented include assessment of the repeatability, coefficients of determination between IPs and grade determining properties, and examples of the yield achieved in different strength classes and combinations of strength classes. The investigated sample comprised more than 900 pieces of timber of Norway spruce (Picea abies) from Sweden, Norway and Finland. For this sample the coefficient of determination between the IP to bending strength and the measured bending strength was as high as R2 = 0.69, while the coefficient of determination between dynamic modulus of elasticity (MOE) and measured bending strength was R2 = 0.53. The yield in high strength classes, C35 and above, becomes about twice as high using the new method/procedure compared to machines using dynamic MOE as IP. A comparison of the performance with what has been presented for machines that are based on X-ray in combination with dynamic excitation indicates that the new method/procedure will surpass such machines as well.