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Measurement of Dynamic Viscoelasticity of Full-Size Wood Composite Panels Using a Vibration Testing Method Cheng Guan, a Houjiang Zhang, a, * John F. Hunt, b Lujing Zhou, a and Dan Feng a
The dynamic viscoelasticity of full-size wood composite panels (WCPs) under the free-free vibrational state were determined by a vibration testing method. Vibration detection tests were performed on 194 pieces of three types of full-size WCPs (particleboard, medium density fiberboard, and plywood (PW)). The dynamic viscoelasticity from smaller specimens cut from the panels was measured using a cantilever beam vibration test apparatus, and the two data sets were compared. A strong linear relationship was discovered between the dynamic viscoelasticity values measured by the vibration detection test and the cantilever beam vibration test. The storage modulus values of the panels were far higher than their loss modulus values, and PW panels had the smallest value of loss modulus. For the panels tested, density had a good linear impact on storage modulus. In comparison with density, logarithmic decrement had a greater linear impact on loss modulus. This study demonstrated that the vibration test method is a valid approach for determining the dynamic viscoelasticity of full-size WCPs.
Key words: Full-size wood composite panel; Dynamic viscoelasticity; Storage modulus; Loss modulus; Vibration testing Contact information: a: School of Technology, Beijing Forestry University, Beijing 100083, China; b: USDA Forest Products Laboratory, 1 Gifford Pinchot Drive, Madison, WI, 53726-2398, USA; *Corresponding author: hjzhang6@bjfu.edu.cn INTRODUCTION Engineered wood composite panels (WCPs) are widely used in furniture production, construction, packaging, transportation, musical instruments, and other sectors. Full-size WCPs refer to panels with a nominal size (length × width) of 2440 mm × 1220 mm, which are the most common in production and sales. To make use of full-size WCPs reasonably and effectively, accurate measurements of their mechanical properties are essential; thus, these measurements have been the focus of research for many years. Modulus of elasticity (MOE) and shear modulus are two key indexes for evaluating the mechanical performance of WCPs. Conventionally, non-destructive techniques have been used to determine these performance parameters in WCPs. Most studies conduct non- destructive testing of MOE and shear modulus of small wood composites specimens and full-size WCPs, with remarkable results (McNatt et al. 1990; Shyamasunder et al. 1993; Larsson 1996; Yoshihara 2011; Wang et al. 2012; Hunt et al. 2013; Guan et al. 2015). However, similar to wood material, WCPs also exhibit dynamic viscoelastic effects. Dynamic viscoelasticity mainly refers to hysteresis phenomena and mechanical losses under the action of cyclic stress and strain. Its main parameter indicators include storage modulus and loss modulus. Storage modulus reflects the material’s elas tic stiffness, and
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Guan et al . (2016). “Dynamic viscoelasticity,” B io R esources 11(2), 4593-4604.
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