WITHDRAWN: Ex-situ toughness and damping research of co-cured bismaleimide matrix composite with aramid nonwoven fabrics

A new kind of functionalized structural composite was prepared by interleaving aramid nonwoven fabrics (ANF) between the carbon fiber reinforced bismaleimide (BMI) composite. It has been observed that the interleaved aramid nonwoven fabrics greatly improved loss factor, interlaminar shear strength, interlaminar fracture toughness, and showed a negligible influence on the flexural strength and modulus of the co-cured composite. Among them, the loss factor of unidirectional co-cured composite with 15 layers of ANF was improved 108% compared to that of the control one, and meanwhile, the Mode I interlaminar fracture toughness (GIC), Mode II interlaminar fracture toughness (GIIC) and interlaminar shear strength were improved 38.6%, 15.5% and 10.2%, respectively. In addition, the structure of the co-cured composite was analyzed via optical microscopy and scanning electrical microscopy in order to study the reinforcement mechanism of ANF. At the same time, a finite element model was developed with commercial software ANSYS 14.5 and modal frequencies and loss factors of the co-cured composite were predicted via "modal" and "transient" analysis steps. At last, the finite element analysis method was verified through comparison between the experimental and numerical results.