Experiment and numerical simulation of compressive strength of interlaminar reinforced and stiffened glass fiber fabric composites with CNT films

Interlaminar reinforcing and stiffening based on CNT films was demonstrated as an effective approach to improve the compressive strength of fabric composites. The influence of carbon nanotube(CNT) films on compressive properties could be directly comprehended through experimental research, and finite element analysis was conductive to in-depth analysis of the improvement mechanism of compressive strength. In this paper, the interlaminar reinforcing and stiffening glass fiber fabric composites with CNT/Epoxy films (CECF/GFRP) were prepared, and the effect of CECF on the macroscopic/microscopic damage morphologies of composite were studied. The finite element model of macro/meso dual-scale and progressive damage model were established, and the compressive stress-strain curves between experiment and finite element simulation were compared, then the damages of composites were analyzed from dual-scale during compression process. Results showed that the intralayer and interlayer compression damages in composite were inhibited due to the introduction of CECF. Compared with GFRP composites, the experimental and finite element simulation values of compressive strength of CECF/GFRP composites were increased by 14.1% and 15.2%, respectively. The finite element models with macro-scale showed that the ability to resist the intralayer fiber buckling and interlayer delamination was enhanced by CECF in the composite. The finite element models with meso-scale indicated that the stress concentrations of the intertwined regions of warp and weft fibers were relieved by CECF, which inhibited the matrix compression damage of the weft yarn fibers and the buckling of the warp yarn fibers. Also, the improvement of interlayer interface strength effectively restrained the interlayer delamination damage, leading to the increase in compressive strength of CECF/GFRP composite.