Experimental and numerical investigation on low-velocity impact of plain-woven bamboo fiber reinforced epoxy resin composites based on multiscale modeling

The investigation of Low-velocity impact (LVI) damage in natural fiber-reinforced composites (NFRCs) was challenging due to the complex damage mechanisms of natural fibers, periodic fiber waviness, structural inhomogeneity, and inherent defects. Herein, a multiscale modeling approach based on the multiscale structural composition of plain-woven natural fiber-reinforced composites (PWNFRCs) characterized by X-ray computed tomography was proposed to accurately capture the LVI response and failure mechanisms of PWNFRCs. The homogenization approach was employed to transfer the material properties of PWNFRCs from the mesoscale to the macroscale. The macroscale LVI numerical model predicted the LVI response and failure mechanisms of PWNFRCs under different energy levels. At impact energy levels of 5J, 7.5J, and 10J, the errors between the experimental peak impact loads and the simulated peak impact loads were 8.29 %, 2.84 %, and 3.70 %, respectively, while the maximum displacement error remained within 8.3 %. The study revealed that the damage failure modes of PWNFRCs under higher-energy impacts progressively evolved into more complex synergistic damage mechanisms, including fiber fracture, matrix cracking, and interlayer delamination. The high consistency between the experimental and simulation results demonstrated that the proposed multiscale modeling approach was reliable in predicting the dynamic response and damage failure mechanisms under various LVI loading conditions.