PSI - Issue 13

Ahmed Sohail et al. / Procedia Structural Integrity 13 (2018) 450–455 Author name / StructuralIntegrity Procedia 00 (2018) 000 – 000

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Table 1. Elastic constants and strength parameters of composite lamina of 3D hybrid woven composite, Munoz et al. (2015)

Elastic moduli (GPa)

Poisson’s ratio

Shear Modulus (GPa)

Elastic Constants

E 1

E 2

E 3

υ 12

υ 13 = υ 23

G 12 4.2 3.8

G 13 = G 23

Carbon

110.1

5.2 8.6

7.5 7.5

0.32 0.31

0.42 0.41

1.95 1.91

Glass

42.5

Strength Parameters (MPa)

X T

X C

Y T

Y C

S L

Carbon

2210 2200

1800 1980

69 68

111 109

42 40

Glass

2.3. Material Properties The composite laminate’s constitutive and damage behavior for the impact process of 3D hybrid woven composite is discussed in previous section. The elastic constants used in the continuum shell elements for the composite laminas are presented in Table 1. The strength parameters for the Hashin damage failure criterion in this study are also summarized in Table 1. The interplay properties for the delamination behavior of traction separation law are listed in Table 2, Shin et al. (2014).

Table 2. Traction separation law for delamination between adjacent plies, Shin et al. (2014) Density (kg/m 3 ) Effective E (MPa) Damage initiation (MPa)

Fracture toughness (mJ/mm 2 ) 0 0 0 40 50 50 0.26 0.52 0.52

BK

ρ

K nn 100

K ss

K tt

η

1200

100

100

1.8

3. Results and Discussions

Ballistic performance under high velocity impact of 3D hybrid woven composite panel on the carbon face and the glass face were simulated using the continuum shell elements for composite laminate and cohesive contact strategy to capture the delamination under impact. The simulation results are depicted in Fig 2 where residual velocity is plotted against the impact velocity, together with the experimental results and numerical simulation conducted by Munoz et al. (2015). The numerical simulation results show that the FE model was able to produce the results which are in good agreement with the experimental results. Although the FE simulation presented good results however there are slight variations in terms of residual velocities measured during the impact process. The residual velocities in the case of impact on carbon face are slightly over predicted and in the case of impact on glass face the values for residual velocities are under predicted. Similarly, in the case of ballistic limit the results in both cases are slightly deviated but remains within the 10% of the experimental data. In addition to the prediction of the residual velocity, the FE simulations also presented the visual insight about the impact process when the impactor impacted either on glass or carbon face and shows that how the process unfolds at different stages of impact which is almost impossible to observe during actual tests. The visual simulation results at different times of the impact process are presented in Fig 3. Cross-sections of the results of the impact simulations are shown for the sake of better understanding of the failure behavior during the process. The failed elements are deleted from the simulation as soon as their failure criteria is reached whether it is fiber compression, fiber tension, matrix tension and matrix compression. Moreover, the delamination between the adjacent plies is also clearly evident from the figure.