Experimental and numerical analysis of low-velocity impact damage of CFRP laminates with negative Poisson ratio (NPR) rubber protective layer.

Carbon fiber-reinforced polymer (CFRP) structures are widely used in aviation industry, which can sustain damage during assembly from low-velocity impact events, decreasing residual stress and bearing capacity. A method of negative Poisson ratio rubber protective layer placing on the CFRP structures has been proposed to address this. The influence of cell angle on the impact response and protection effect were first investigated in this study. The experimental results indicate that the negative Poisson ratio rubber protective layer enhanced the impact resistance of the CFRP laminates, which reduces 33.1% the impact peak force and 17.5% the absorbed energy. Moreover, the impact resistance of CFRP with increases with the increasement of the cell angle. A low-velocity impact finite element model was developed with mixed-mode damage criterion for laminates and the hyperelastic model for rubber. The simulation results were validated with the experiment results in impact response and delamination damage. Additionally, the impact response and resistance were analyzed by varying seven different structural parameters of the protective layer to reveal the influence of relative volume. The experiment and simulation results demonstrated that the impact resistance increased with increasing cell angle and relative volume of the negative Poisson ratio rubber protective layer. • The influence of structural parameters on the impact resistance of rubber negative Poisson ratio protective layer was revealed by low-velocity impact tests. • The internal damage and damage mechanism of composite laminates were simulated with a mixed-mode damage criterion. • The relation between the relative volume of rubber negative Poisson ratio protective layer and its impact resistance was discussed by simulation results. • The low-velocity impact process of the composite laminate with the rubber negative Poisson ratio protective layer was detailed. [ABSTRACT FROM AUTHOR]