A microscale modeling method for predicting the compressive behavior of 3D needled nonwoven fiber preforms

Abstract

The through-thickness compressive mechanism of 3D needled nonwoven fiber preforms is complicated due to the complex fiber structure and enormous fiber-to-fiber contacts. This work developed a microscale modeling method to predict compressive behavior of carbon fiber nonwoven preforms. A newly-developed virtual fiber is proposed based on the generalized beam elements, for which the low bending stiffness of the fiber is calibrated by experimental data and decoupled from the high tensile stiffness. The feasibility of the proposed virtual fiber method is demonstrated through a simulation example of three-point bending of 6 k carbon fiber yarn. Influence of modeling parameters including amount of virtual fibers in the yarn and the element length of virtual fibers on the simulations is analyzed. High precision model of 3D needled preform is then generated using the proposed virtual fiber method. Through-thickness and axial compressive deformations of the preform are simulated. The predicted load–displacement curves agreed well with the experimental results.