Design optimization of bioinspired helicoidal CFRPP/GFRPP hybrid composites for multiple low-velocity impact loads

Abstract

Low-velocity impact (LVI) on continuous fiber reinforced thermoplastics (CoFRTPs) has been extensively studied with a focus on single material. Impact characteristics and optimal design of hybrid CoFRTPs have not been well addressed even though they are of considerable advantages in balancing cost and performance. This study aims to develop design optimization of bio-inspired hybrid CoFRTPs to resist multiple impact loads. In this study, the LVI behaviors of carbon fiber reinforced polypropylene (CFRPP) and glass fiber reinforced polypropylene (GFRPP) composites were first characterized experimentally, respectively. Three typical failure modes were identified in both the CFRPP and GFRPP specimens, and GFRPP exhibited better impact toughness than CFRPP. Second, a progressive failure model (PFM) was developed for finite element analysis, and numerical results in LVI damage modes and force-displacement curves agreed quite well with the corresponding experimental data. Third, parametric studies indicated that peak energy absorptions of CFRPP and GFRPP specimens respectively decreased by 20.9% and 25.5% with impact angles varying from 0° to 30°, and design of helicoidal stacking configuration can effectively enhance the LVI resistances for both the CFRPP and GFRPP specimens. Hybridization of CFRPP and GFRPP enables to improve LVI resistances and reduce the material costs. Finally, a multiobjective optimization was performed to optimize material cost and LVI resistance of helicoidal CFRPP/GFRPP hybrid composites accounting for multiple impact loads, which increased the peak energy absorption by 31.0% and reduced material cost by 33.4% compared with the baseline design. This study is anticipated to introduce an optimum configuration of hybrid composites for bearing multiple low-velocity impact loads.