Numerical investigation of the compressive behavior of 2.5D woven carbon-fiber (2.5D-CFRP) honeycomb and experimental validation

In this work, the quasi-static compression behavior of a 2.5D woven carbon-fiber (2.5D-CFRP) honeycomb was numerically investigated by using two optimized models based on a conventional macro-mechanical model and the representative volume element (RVE) model. We introduced a viscosity regularization criterion into the conventional macro-mechanical model to improve the accuracy of the simulations. The relationship between the viscosity coefficient and simulation accuracy was analyzed using the displacement-load profile of the 2.5D-CFRP honeycomb under quasi-static compression. We further clarified the damage mechanism during the crushing of the 2.5D-CFRP honeycomb. An RVE model simulation was performed by using the combined VUMAT subroutine, which represented the damage state of fibers in different lay-up directions of the 2.5D-CFRP honeycomb. The results showed that the modified macro-mechanical model represented the twisting and folding mechanism of the honeycomb walls during quasi-static compression rather than the damage of the fibers at the intersection of the honeycomb walls.