Application of Impact Imaging Method on Nondestructive Detection of Void Defects in Sandwich-Structured Immersed Tunnel

Figure 8

Time history curves of response waveforms of the measuring points. (a) a₁ dense region (5 cm from T-stiffener), (b)a₂ dense region (10 cm from T-stiffener), (c) b₁ void region (10 cm from T-stiffener), and (d) b₂ void region (10 cm from T-stiffener).

(a)

(b)

(c)

(d)