A rate-dependent constitutive model for 3D printed discontinuously carbon fiber composite foam

This study investigates the effects of loading rate on the viscoelastic constitutive behavior of 3D-printed discontinuously carbon fiber-reinforced open-cell foams. A new viscoelastic constitutive model is developed and implemented as a VUMAT in ABAQUS. Through uniaxial compression experiments (0.1–500 mm/min) and computational analyses of Kelvin foam structures with 1–64 cells, three critical findings emerge: The Young’s modulus and yield stress exhibit pronounced rate dependence, increasing by 64.2–142.1% and 58.0–104.8%, respectively, across the tested loading rate range; Relative density dominates mechanical performance, with the highest-density foam showing 28.2–31.1 times greater stiffness than the lowest-density counterpart; Multiscale simulations demonstrate excellent agreement (<5% error) with experimental data, validating the model’s predictive capability for cellular composites. These findings provide valuable insights into the design and application of viscoelastic foams in structural and energy-absorbing systems.