Study on elastic constants of laminated veneer lumber by dynamic test

Laminated veneer lumber (LVL) is a structural composite lumber that has the advantages of uniform structure, high strength, and flexible size compared with natural solid wood. It is widely used in the timber industry. This paper aims to test the elastic constants of LVL using a dynamic method. It focuses on Populus deltoides LVL as the research subject and proposes a 1/3-span patch method of square-section cantilever beam for dynamic testing of wood Poisson’s ratio. The elastic modulus, shear modulus, and Poisson's ratio of LVL were determined through dynamic testing using the cantilever plate transient excitation method. The accuracy of the Poisson's ratio of LVL tested with the 1/3-span patch method was verified through first-order bending mode stress–strain analysis. These results were further confirmed using a static four-point bending method. The conclusion reveals that the relative error of the LVL Poisson's ratio obtained using the 1/3-span patch method for cantilever beams and the first-order bending mode method for cantilever plates ( \({\sigma }_{y}\) ${\sigma }_y$ =0 patch method) testing is 2%. The longitudinal and transverse Poisson's ratios of LVL tested with the 1/3-span patch method for cantilever beams match those obtained through the first-order bending mode method for cantilever plates and the four-point bending method. The relative error between LVL longitudinal and transverse dynamic beam elastic modulus test values and static four-point bending test values is no more than 5%. The relative error between LVL longitudinal shear modulus dynamic and static test values is 4.8%, and the results are consistent. In conclusion, the dynamic method is effective for testing the longitudinal and transverse Poisson's ratio, elastic modulus, and shear modulus of LVL. It is also more convenient than the static test method.