On the mode I and mode II fatigue delamination growth of CFRPs modified by electrospun Bis-maleimide resin

In the current work, fatigue life estimation for delamination growth of modified unidirectional (UD) carbon fiber reinforced plastics (CFRPs) with Bis-maleimide (BMI) resin under Mode I and Mode II loading conditions is assessed. More precisely, BMI resin containing or not four layered (4L) graphene nanoplatelets (GNPs) at the amount of 1 wt% was integrated locally into the mid-thickness area of high performance CFRPs by solution electrospinning process (SEP) technique. After manufacturing process, reference and modified CFRPs with (a) BMI and (b) BMI containing GNPs were used for fatigue onset and propagation tests. All double cantilever beam (DCB) and end-notched flexure (ENF) samples were both tested under displacement control conditions. During the tests, a travelling microscope was utilized to measure the crack length at the end of precise loading cycles while load and delamination length were recorded at the same time. Based on experimental results, BMI modified CFRPs presented the best resistance to delamination under Mode I fatigue loading conditions, while the BMI and GNP modified CFRPs exhibited the best performance under Mode II fatigue loading conditions. Taking into consideration of the obtained results, this approach can be considered a viable solution for increasing the delamination resistance of CFRPs.