Fig. 1. Yee cells in medium space divided by FDTD method

Fig. 2. Results before and after modulation of terahertz pulse signal. (a) In time-domain; (b) in frequency-domain

Fig. 3. Structural drawing of FRP production

Fig. 4. Geometric model for THz pulse simulation detection. (a) Geometric model of debonding defects; (b) geometric model of delamination defects

Fig. 5. Optical parameter curves. (a) Refractive index curve; (b) extinction coefficient curve

Fig. 6. Optical path map for terahertz pulse simulation with adhesive debonding model. (a) Without debonding defects; (b) with debonding defects

Fig. 7. THz pulse simulation results with debonding defects. (a) No defects; (b) debonding defects with ΔH₁=60 μm; (c) debonding defects with ΔH₁=100 μm; (d) debonding defects with ΔH₁=200 μm

Fig. 8. Optical path for THz pulse simulation with FRP delamination model. (a) No defects; (b) one layered delamination defects; (c) two layered delamination defects

Fig. 9. THz pulse simulation results with delamination defects. (a) No defects; (b) one layered delamination defect with ΔH₂=80 μm; (c) two layered delamination defects with ΔH₂=80 μm