Mechanical and damping properties of bismaleimide resin co-cured composite with nonwoven fabrics

A structural damping composite was prepared by co-curing method with aramid nonwoven fabrics (ANF) and polyamide nonwoven fabrics (PNF) as interleaves. Dynamic mechanical indicators such as storage modulus and loss factors were measured and analyzed by DMA. Furthermore, static mechanical properties were estimated through measuring the flexural properties and interlaminar shear strength of the co-cured composites. In addition, single cantilever beam forced resonance experiment and free vibration decaying experiment were carried out. It is observed that nonwoven fabrics could form the non-reactive bicontinuous phase structure with the matrix in the interlaminar. The flexural strength and modulus of [0°]₁₆ composite with ANF are nearly 10% higher than those of the control sample. Moreover, the flexural strength of [± 45°]_4s composite with ANF is higher than that of the control sample as much as 50%, which is also higher than that of the composite with PNF. Additionally, the damping properties of the co-cured composites are also improved as a result of the formation of the resin-rich zones and the increase of the interfaces. Among them, the loss factor of [0°]₁₆ and [± 45°]_4s composite with PNF is 0.0026 and 0.0064, respectively, which is more than those of the control one as much as 116.7% and 14.3%.