Finite element analysis of textile composite preform stamping

The forming or draping of a textile composite preform may result in large c hanges in the fibrous microstructure of the preform. This change in the loc al fiber orientation leads to significant changes in the fabric permeabilit y as well as the mechanical properties of the ensuing composite structure. Therefore, this change in orientation of the tows of the preform needs to b e known accurately to calculate the various effective properties of the com posite. A new finite element approach for stamping analysis of a plain-weav e textile composite preform has been developed. This model is simple, effic ient and can be used in the existing finite element codes. The model repres ents the preform as a mesh of 3-D truss elements and 3-D shell elements. Th e truss elements model the tows, which are allowed to both scissor and slid e relative to one another. The shell elements represent a fictitious materi al that accounts for inter-tow friction and fiber angle jamming. The model takes into account large strains and large deformations. In-plane uniaxial tension tests have been performed on plain-weave specimens for determining the constitutive law of the transforming medium and to show the inter-tow s liding. Application of the model is demonstrated by simulating the stamping of a preform by a spherical punch. The results from the simulation show go od correlation with results from the experiments. (C) 2001 Elsevier Science Ltd. All rights reserved.