Three-dimensional mechanical properties of dry carbon fiber tows subjected to cyclic compressive loading

Abstract

Characterizing the response of compressed dry fibrous reinforcements is a key feature to control liquid composite molding processes. Considering preforms manufactured by automated dry fiber placement, supplementary information are needed, since cyclic loading occurs, during which the mechanical properties of tows evolve. In this way, an extensive characterization procedure is proposed in this article. Each mechanical feature, such as nonlinearity, springback, irreversibility, stabilization, and strain rate dependence, is analyzed, and when possible, related to microstructural observations. Particular attention is paid to the response in other directions than the compressed one. Finally, from this characterization, a route to modeling is drawn: analogies with other classes of materials are proposed, leading to choices on the modeling of each mechanical property.