Effect of the microstructure of GMT on its mechanical properties

Abstract The effect of microstructure of GMT on its mechanical properties was investigated. The studied microstructure includes the fiber mat structure, the through‐thickness glass fiber content‐distribution of GMT sheets and the void content. The fiber bundle GMT (FB‐GMT) and the single fiber GMT (SF‐GMT) were prepared by the impregnation process using continuous fiber bundle mats and continuous single fiber mats as reinforcement, respectively. The mechanical properties of the two GMTs were compared to reveal the difference in reinforcing effect between the fiber bundle and the single fiber. The effect of needle density of the fiber mat on the mechanical properties of GMT was also studied, which indicated that needle‐punching improves the mechanical properties of GMT, and that the optimal needle density is 40∼60 needles/cm². The through‐thickness glass fiber content‐distribution, which is inhomogeneous and can be modified by the film‐stacking method, significantly affects the mechanical properties of GMT. Finally, the study of the effect of void content indicated that with increasing void content, the strength and modulus of GMT decrease, but the impact property increases slightly.