bioresources. com
PEER-REVIEWED ARTICLE
A density difference between small specimen and full-size WCP can also lead to a damping ratio difference between the samples (Wang et al. 2012; Hunt et al. 2013). To eliminate the impact of a damping ratio difference between small specimen and full-size WCP on the E ” s of a small specimen, the impact of density and logarithmic decrement on E ” s was accounted for by Eq. 9,
' ' ' ' b π
= E E ”
(9)
s
b
s
where E ” b is the adjusted loss modulus of small specimen, and Δ and Δ s are the logarithmic decrements of full-size WCP and small specimen, respectively. s is the unadjusted loss modulus of small specimen, E ” After adjusting the dynamic viscoelasticity for the small specimen, the dynamic viscoelasticity of full-size WCPs and small specimens were compared (Fig. 3). There was a statistically significant, highly correlated linear relationship between storage modulus of all the panels tested and their small specimen. Similarly, the loss modulus was highly correlated with the small cantilever specimens. The linear correlations of storage modulus and loss modulus were 1.033 and 1.012, with the coefficients of correlation of 0.951 and 0.968, respectively, revealing that determining dynamic viscoelasticity of full-size WCPs by the vibration testing method was very effective and feasible. (a) (b)
2000 2500 3000 3500 4000 4500 5000 5500 6000
110 130 150 170
y = 1.033x r=0.951
y = 1.012x r=0.968
PB MDF PW
PB MDF PW
30 50 70 90
30 50 70 90 110 130 150 170 E " b /MPa
2000 3000 4000 5000 6000 E ' b /MPa
Fig. 3. Relationship of dynamic viscoelastic properties between full-size panels (y-axis) and smaller cantilever beam specimen (x-axis) (a) storage modulus, and (b) loss modulus
CONCLUSIONS 1. The laboratory testing apparatus provides an easy method to determine dynamic viscoelasticity of full-size WCPs fast and accurately. 2. A statistically significant and highly correlated linear relationship existed between the dynamic viscoelasticity of the panels tested in the vibration detection test and small specimens tested using the cantilever beam vibration test.
4602
Guan et al . (2016). “Dynamic viscoelasticity,” B io R esources 11(2), 4593-4604.
Made with FlippingBook Digital Proposal Creator