3种边界条件下足尺定向刨花板的模态灵敏度和振动模态研究

【目的】研究完全自由、四节点支承和两对边简支3种边界条件下足尺定向刨花板的模态灵敏度和振动模态,为开展3种边界条件下足尺定向刨花板弹性常数振动检测结果的对比研究奠定基础。【方法】以4种厚度的足尺定向刨花板为研究对象,采用有限元软件COMSOL Multiphysics对完全自由、四节点支承和两对边简支的足尺定向刨花板进行了模态灵敏度分析,分别确定这3种边界条件下对其长度和宽度方向的弹性模量与面内剪切模量这3个弹性常数灵敏度最高的模态;通过试验模态分析测得足尺定向刨花板在这3种边界条件下的前9阶振动模态参数,并对比和分析其在这3种边界条件下的振动模态参数检测结果。【结果】计算和试验模态分析得到的这3种边界条件下足尺定向刨花板的前9阶模态振型形状和阶次分别是相同的;足尺定向刨花板在这3种边界条件下的前9阶模态中,除模态(m, 0)、(0, 2)和(1, 1)外,其余模态均为单一方向的弯曲和扭转或不同方向弯曲的叠加模态;用于计算足尺定向刨花板长度和宽度方向的弹性模量与面内剪切模量的最高灵敏度模态,在完全自由下为模态(2, 0)、(0, 2)和(1, 1),对应阶次分别为第2、4和1阶;在四节...

Modal sensitivity and vibration mode of full-size oriented strand board panel under three boundary conditions

  Objective  To lay the foundation for the comparative study on vibration testing results of elastic constants for full-size oriented strand board (OSB) panel under these three boundary conditions, the modal sensitivity and vibration mode of full-size OSB panel under completely free boundary condition, supported on four nodes and simply supported on two opposite sides were studied, respectively.   Method  Full-size OSB panels with 4 kinds of thicknesses were used as study object. The modal sensitivity analysis of full-size OSB panels under these three boundary conditions was carried out using finite element software COMSOL Multiphysics, and the modes with the highest sensitivity corresponding to their three elastic constants including modulus of elasticity (E_x and E_y) in the length and width direction as well as in-plane shear modulus G_xy were obtained; the first nine vibration modal parameters of full-size OSB panels under these three boundary conditions were measured through experimental modal analysis, and the testing results of their vibration modal parameters under three boundary conditions were compared and analyzed.   Result  The modal shape and order of the first nine mode of full-size OSB panel under three boundary conditions were separately identical through experimental and theoretical modal analysis; except for mode (m, 0), (0, 2) and (1, 1), the first nine modes of full-size OSB panel under three boundary conditions were superimposed modes for bending and torsional in single direction or bending in different directions; the modes with the highest sensitivity for calculating E_x, E_y and G_xy of full-size OSB panel were mode (2, 0), (0, 2) and (1, 1) corresponding to the second, fourth and the first order under completely free boundary condition, mode (2, 0), (0, 2) and (2, 1) corresponding to the first, fourth and the third order for being supported on four nodes, mode (2, 0), (2, 2) and (2, 1) corresponding to the first, fifth and the second order for being simply supported on two opposite sides.   Conclusion  From the perspective of vibration mode, it is feasible for performing the modal sensitivity analysis and vibration modal test of full-size OSB panel under three boundary conditions based on theoretical and experimental modal analysis method.