Effect of polyurea coating on low-velocity impact properties of unidirectional carbon fiber-reinforced polymer composites plates

To improve the impact performance of unidirectional carbon fiber-reinforced polymer composites (CFRP) for engineering structures, a polyurea coating was sprayed on the CFRP surface. Effects of the polyurea spraying position and thickness on the CFRP impact properties were studied using a low-velocity impact test and computed tomography. The results show that the front-coated polyurea layer reduces the impact energy acting on CFRP because of the consumption of impact energy so that the internal damage of CFRP is smaller and retains higher CFRP bearing capacity than that of other spray positions. The rear-coated polyurea layer has a supporting effect on CFRP, thus the plastic deformation of CFRP is reduced and the structural integrity of CFRP is maintained. Under the impact load, the damage mainly occurred inside the CFRP, and almost no damage occurred in the polyurea layer. The damage in CFRP is mainly the split along the fiber direction, and it is trapezoidal and delaminated from the impact surface to the back-impact surface.