Table 2.

The material properties of the balsa wood and glass fiber/epoxy composite [30,31].

Material	${\mathit{E}}_{11}$ (GPa)	${\mathit{E}}_{22}$ (Gpa)	${\mathit{G}}_{12}$ (GPa)	${\mathit{\nu }}_{12}$	$\mathit{\rho }$ (kg/m3)
Balsa wood	0.4	0.4	0.16	0.1	125
Glass fiber/Epoxy	41.0	9.0	4.10	0.3	1890