Measurement of dynamic modulus of elasticity and damping ratio of wood-based composites using the cantilever beam vibration technique

The non-destructive testing technique has been widely used to determine the dynamic mechanical properties of wood and wood-based composites, such as dynamic modulus of elasticity (E-d) and damping ratio (zeta). The cantilever beam vibration method is a cost-efficient and time-saving technique that was employed in this study to measure Ed and values of three commercial wood-based composites, i.e. plywood (PLW), high density fiberboard (HDF), and oriented strand board (OSB). The E-d and zeta values were determined in light of the spectral analysis on the first natural frequency and the first and fifth amplitudes of vibration in the vertical direction, which was triggered by tapping one end of a specimen free of the support. To verify the values, the static bending tests were conducted. It was found that the E-d values of three kinds of wood composites tested were slightly higher than the static modulus of elasticity (E-5). There existed a good linear agreement between E-d and E-s. The zeta value of PLW was the largest among three composites, and the OSB showed the lowest zeta. (C) 2011 Elsevier Ltd. All rights reserved.

无损检测技术已被广泛用于测定木材及木质复合材料的动态力学性能，例如动态弹性模量（$E_d$）和阻尼比（$\zeta$）。悬臂梁振动法是一种经济高效且省时的技术，本研究采用该方法测量了三种商用木质复合材料，即胶合板（PLW）、高密度纤维板（HDF）和定向刨花板（OSB）的$E_d$和$\zeta$值。通过对试件无支撑一端敲击所引发的垂直方向上的一阶固有频率以及一阶和五阶振动振幅进行频谱分析来确定$E_d$和$\zeta$值。为了验证这些值，进行了静态弯曲试验。结果发现，所测试的三种木质复合材料的$E_d$值略高于静态弹性模量（$E_s$）。$E_d$和$E_s$之间存在良好的线性一致性。在三种复合材料中，胶合板的$\zeta$值最大，定向刨花板的$\zeta$值最低。© 2011爱思唯尔有限公司。保留所有权利。