PSI - Issue 61

Yogesh Kumar et al. / Procedia Structural Integrity 61 (2024) 322–330 Y. Kumar et al., / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4a shows the complete setup of the model to describe the material behaviour, as discussed earlier in Section 3.The results from the numerical models were extracted in terms of load-displacement curve and compared with the experiment, as shown in Fig. 4b. The delamination initiation and the migration through the 0°/0° interface were well captured by the model, as depicted through the linear slope of the curve. Peak force estimated using the [*MAT_138] material model is 82.80 N with an error of 1.22 %. The progressive failure in the model was also accurately estimated by the developed model. It can be concluded that the predicted response is in good agreement and within the 10 % error bound of the experiments.

Fig. 5. (a) 3D finite element model for the quasi-static compression of the cross-ply composite with details on the boundary conditions and mesh size (b) Comparison of the stress-strain response obtained through the calibrated numerical model and the experiment study from the 8 ply sample. For the quasi-static in-plane compression model, details on the model setup are provided with the comparison of the mechanical response (stress-strain curve) obtained through experiments and simulations, as shown in Fig. 5. Overall, the numerical prediction for the quasi-static in-plane compression of the 8 ply sample showed a good resemblance with the experimental data, as shown in Fig. 5b. The red dash box shows the region involved for achieving the stress-equilibrium by the composite sample during the experiments (Ou et al., 2016). The elastic response in the stress-strain curve was well predicted, with only 7.8 % error in the stiffness compared to the experiments. The variation in the post-elastic region is due to the simplified constitutive damage models incorporated in the [*MAT_55] material model. In addition, the predicted maximum stress value 138.01 MPa with error of 7.2 % is in good agreement with the experimentally evaluated maximum stress of 128.68 MPa. 5. Conclusion The presented study was aimed to experimentally and numerically characterize the in-plane compressive behaviour of the cross-ply carbon-fiber-reinforced-polymer composites with variable ply thickness and quantify the correlation between the global in-plane compressive strength and the maximum failure strains with the thickness of the 90° plies in the composite sample. The key outcomes from this present research are as follows: 1. The interlaminar failure mode consistently initiates the damage within the plies of the sample, leading to intralaminar failure propagation and the generation of fracture plane. The propagation of the interlaminar failure restricts with the increase in the thickness of 90° plies. 2. The DCB model developed can predict the force-displacement response within the 10 % error range of the experimental data. This model can be used for defining the interlaminar interface in the laminated composites for Mode-I loading.