Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types

Table 2 Parameters of the relationship \( { \tan }\delta = {1}{0^{{ - A}}} \times {\left( {E\prime /\gamma } \right)^{{ - B}}} \) as obtained by regressions on different samples

	N specimens	A	B	\( {\text{R}}_{\text{direct}}^2{ \tan }\delta = f\left( {E\prime /\gamma } \right) \)	\( R_{\text{combined}}^2{ \tan }\delta /\left( {E\prime /\gamma } \right) = {\text{f}}\left( {E\prime /\gamma } \right) \)
All samples	1,792	1.322	0.692	0.50	0.86
Softwoods (normal wood = NW)	140	1.222	0.639	0.76	0.95
Hardwoods (NW) with high extractives content	1,153	1.474	0.620	0.57	0.90
Hardwoods (NW) with low extractives content	221	1.231	0.677	0.73	0.94
25 softwood species^a	1,227	1.23	0.68		0.91
30 hardwood species^b	118	1.34	0.62		0.83

Constants are derived from regressions based on E′/γ expressed in GPa. \( R_{\text{direct}}^2 \) and \( R_{\text{combined}}^2 \) = coefficient of determination obtained from plotting tanδ directly versus E′/γ, or tanδ/(E′/γ) versus E′/γ, respectively
^aOno and Norimoto (1983)
^bOno and Norimoto (1984)

ISSN: 1297-966X