Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation

Table 2

Four kinds of media wave impedance relationship at room temperature.

Medium	ρ (kg/m^3)	c (m/s)	η (kg/(m^2·s))	Δη (kg/(m^2·s))
PMMA	1190	2320	2.7608 × 10^6	—
Air	1.25	340	425	2.760375 × 10^6
Soil	1800	1000	1.8 × 10^6	0.9608 × 10^6
Water	998	1497	1.494006 × 10^6	1.266794 × 10^6