Bamboo node effect on the tensile properties of side press-laminated bamboo lumber

摘要

At present, most of the existing studies on bamboo nodes focus on the raw bamboo. There is still a lack of researches on the nodes in side press-laminated bamboo lumber (LBL). However, after processing, bamboo nodes in the laminated bamboo lumber are different from the raw bamboo nodes in terms of performance. Therefore, this paper carried out tests to analyze the influence of bamboo node on the tensile properties parallel to grain of side press-laminated bamboo lumber. A total of 180 specimens were divided into six groups, and the number and position of the bamboo nodes at the specimen in each group were different. The effects of these factors on the strength, elastic modulus, and Poisson's ratio of the side press-laminated bamboo lumber under tension parallel to grain were obtained. The tensile failure of side press-laminated bamboo lumber was a brittle fracture, and the typical failure mode can be classified into three types. The mean value for tensile strength was 127.18 MPa when there was no bamboo node, while the mean value was 89.99-107.37 MPa when there were one to three bamboo nodes. The number of bamboo nodes would significantly affect the tensile properties parallel to grain of side press-laminated bamboo lumber, whereas the position of bamboo nodes has an insubstantial impact. Comparisons with other research results were also carried out. A series of formulas were proposed based on the test results to reflect how the node influenced the mechanical properties of side press LBL under tensile conditions.