The Dynamic Impact Response of Polyurea-Coated Unidirectional Graded Auxetic Honeycomb Sandwich Panels

To investigate the enhancement mechanism of polyurea elastomeric coating on the anti-impact of unidirectional graded auxetic honeycomb sandwich panels. With the help of LS-DYNA finite element analysis software, the dynamic response of the sandwich panel to a cylindrical impact is simulated numerically. The influence of polyurea coating by the method of outline volume analysis position on its anti-impact is first analyzed. On this basis, the effects of impact velocity, impact angle of the cylinder, coating thickness, and coating area of polyurea elastomer on the sandwich panel are further discussed by the method of outline volume analysis. Finally, the polyurea thickness on both sides of the coated polyurea sandwich panel (type C) on both sides is optimized. The results show that the coating of polyurea elastomer can effectively enhance the impact protection performance of sandwich panels. By comparison with sandwich panel of uncoated structure (Type O), type C achieves the best anti-impact, and the maximum post deflection (Defl) is reduced by 61.6%. The increase in impact velocity and the decrease in impact angle will increase the maximum deflection of the sandwich panel if other variables remain constant. When the cylinder impact speed is certain, preference is given to sandwich panels that are thicker, larger, and have polyurea sprayed on both sides. The optimization by the response surface method shows that the sandwich panel with the best anti-impact may be obtained when the polyurea thickness ratio of the impact side to the back side is 1.3:0.7.