114 M A T E R I A L S E V A L U A T I O N • J A N U A R Y 2 0 2 0 ME TECHNICAL PAPER w computational nde for composites 5 8 –8 –6 –4 2 0 2 4 6 8 0.15 0.1 0.05 7 6 x (mm) 5 8 –8 –6 –4 2 0 2 4 6 8 0.3 0.2 0.1 7 6 x (mm) Figure 7. Displacement distribution (in GPa): (a) displacement (u1) distribution in pristine multilayered plate (b) displacement (u3) distribution in multilayered plate. (a) (b) –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 2 4 6 2 4 1.5 1 0.5 x (mm) 2 4 6 8 –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 1.5 1 0.5 x (mm) 2 4 6 8 Figure 8. Measurement of stress and pressure field (in GPa): (a) stress11 (σ11) distribution in 0° and 90° degraded multilayered plate and (b) stress33 (σ33) distribution in multilayered plate. (a) (b) 5 8 –8 –6 –4 2 0 2 4 6 8 0.15 0.1 0.05 7 6 x (mm) 5 8 –8 –6 –4 2 0 2 4 6 8 0.3 0.2 0.1 7 6 x (mm) Figure 9. Displacement distribution (in GPa): (a) displacement (u1) distribution in 0° and 90° degraded multilayered plate (b) displacement (u3) distribution in multilayered plate. (a) (b) –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 1 2 3 4 5 1.5 1 0.5 x (mm) 2 4 6 8 –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 2 4 1.5 1 0.5 x (mm) 2 4 6 8 Figure 10. Measurement of stress and pressure field (in GPa): (a) stress11 (σ11) distribution in 0° degraded multilayered plate (b) stress33 (σ33) distribution in multilayered plate. (a) (b) z (mm) z (mm) z (mm) z (mm) z (mm) z (mm) z (mm) z (mm)

J A N U A R Y 2 0 2 0 • M A T E R I A L S E V A L U A T I O N 115 Wavefield Modeling of 0° and 90° Degraded 4-Ply Plate The stress and displacement wavefields were calculated for a 0° and 90° degraded ply in a 4-ply plate that is, the 90/0-degraded/90-degraded/0 plate. In the stress field plot, the lower and upper section (5 mm each) of the plots represent the pressure fields inside the water, and the midsection (3 mm) represents the stress field inside the solid plate. The wavefields are first shown for normal inci- dence. The stresses (s11 and s33) and pressure fields in transversely isotropic material, which are shown in Figures 8a and 8b, respectively, were computed. Similarly, the displacement fields (u1 and u3) are shown in Figures 9a and 9b. Wavefield Modeling of 0° Degraded 4-Ply Plate The stress and displacement wavefields were calculated for a 0° degraded ply in a 4-ply plate that is, the 90/0-degraded/90/0 plate. The stresses (s11 and s33) and pressure fields, which are shown in Figures 10a and 10b, respectively, were computed. Similarly, the displacement fields (u1 and u3) are shown in Figures 11a and 11b. Wavefield Modeling of 90° Degraded 4-Ply Plate The stress and displacement wavefields were calculated for a 90° degraded ply in a 4-ply plate that is, the 90/0/ 90-degraded/0) plate. The stresses (s11 and s33) and pressure fields, which are shown in Figures 12a and 12b, respectively, were computed. Similarly, the displacement fields (u1 and u3) are shown in Figures 13a and 13b. 5 8 –8 –6 –4 2 0 2 4 6 8 0.15 0.1 0.05 7 6 x (mm) 5 8 –8 –6 –4 2 0 2 4 6 8 0.3 0.2 0.1 7 6 x (mm) Figure 11. Displacement distribution (in GPa): (a) displacement (u1) distribution in 0° degraded multilayered plate (b) displacement (u3) distribution in multilayered plate. (a) (b) –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 2 4 1.5 1 0.5 x (mm) 2 4 6 8 –8 –6 –4 –2 0 0 5 8 13 2 1.5 1 0.5 2 1.5 1 0.5 x (mm) 2 4 6 8 1 2 3 4 5 Figure 12. Measurement of stress and pressure field (in GPa): (a) stress11 (σ11) distribution in 90° degraded multilayered plate (b) stress33 (σ33) distribution in multilayered plate. (a) (b) 5 8 –8 –6 –4 2 0 2 4 6 8 0.15 0.1 0.05 7 6 x (mm) 5 8 –8 –6 –4 2 0 2 4 6 8 0.3 0.2 0.1 7 6 x (mm) Figure 13. Displacement distribution (in GPa): (a) displacement (u1) distribution in 90° degraded multilayered plate (b) displacement (u3) distribution in multilayered plate. (a) (b) z (mm) z (mm) z (mm) z (mm) z (mm) z (mm)