PSI - Issue 50

Alexander Eremin et al. / Procedia Structural Integrity 50 (2023) 73–82 Alexander Eremin / Structural Integrity Procedia 00 (2019) 000 – 000

80 8

CS=0.13%

(a)

NOPD=0.04

CS=0.2%

(b)

NOPD=0.5

CS=0.6%

(c)

NOPD=1

Fig. 7. Changes in the shape and longitudinal strain fields within the compression of the plate impacted by 25.65 J. Figures are rotated by 90° counterclockwise.

The second specimen also exhibits buckling that starts nearly from the longitudinal strain of ~0.2% (Fig. 8b). The full-length extensometer demonstrates the change of the slope while the corner extensometers fully change their behavior: the initial compressive strains are compensated by the buckling that induced tensile strains. The extensometers in the bottom are more influenced by these tensile strain than the upper located.

8.55 J

17.10 J

25.65 J

(a)

(b)

(c)

Fig. 8. Extensometer curves obtained after CAI testing of orthotropic [0/90] 5S CRFP with different energy impacts.

The third specimen (Fig. 8с) exhibits the most complex fracture. The first evidence of bending strains occurs after 0.17% and is accompanied by the change of the slope of the curves obtained by corner extensometers. Bottom extensometers exhibit higher compressive strains while uppers have lower. The first partial fracture occurs at 0.47%. It leads to vertical asymmetry for 2- 2’ and 3 - 3’ extensometers (located on the right side of the plate) as a strain jump while it is not seen for 1- 1’ and 4 - 4’ extensometers located on the left si de. The second partial fracture occurs at 0.63%. The highest stress was achieved for this strain but the final fracture has not occurred. Deflection has reached