A comparative study of the experimental and modeling for the creep-recovery behaviors of bamboo flour/polyethylene composites enhanced with a “rigid-flexible” grid structure

Creep behavior significantly restrict the application of natural fiber polymer composites (NFPCs) in high-value engineering fields. This study addresses this issue by constructing a novel rigid-flexible grid structure in bamboo flour/polyethylene composites (BPCs). This structure is constructed by incorporating a sandwich sheet composed of carbon fabric mesh prepreg (CFMP) and high-toughness casting films (MSF) through multi-layer co-extrusion. The resulting composites (BPC-CFMP-F) exhibited substantially improved bending properties and creep resistance. Bending strength increased by 88.2 %, 96.4 %, and 101.7 % at −20 °C, 30 °C, and 80 °C, respectively, while creep strain decreased by 18.2 %, 33.3 %, and 41.9 %. The Burgers and Findley models were employed to simulate the creep strains at different temperatures. An innovative method involving the mathematical fitting of recovery strains post-mirror processing offered novel insights into the deformation behavior and recovery dynamics of the composites. The Findley model demonstrated exceptional precision, with coefficients exceeding 0.99). This accuracy enabled the development of general constitutive equations to describe strain-related stress during both creep and recovery stages. These advancements enhance the application potential of NFPCs in contexts demanding high creep resistance and offer a reliable analytical tool for a comprehensive understanding of both creep and recovery phenomena. • A continuous rigid-flexible structure was constructed within BPCs via co-extrusion. • The innovation led to substantial enhancements in bending properties and creep resistance. • The creep strain data were modeled using both the Burgers and Findley models. • General constitutive equations for both the creep and recovery stages were developed.