Hydrothermal behavior of pure PA 6 and homogenization of discontinuous long carbon fiber‐reinforced PA 6

Abstract Polymer‐based composites play a crucial role in lightweighting applications by providing resource‐efficient semi‐structural materials. Among these, polyamides, in particular polyamide 6 (PA 6), serve as widely used matrix materials in various technical applications, especially in fiber‐reinforced composites. The mechanical properties and performance of PA 6 are significantly affected by environmental factors such as temperature and humidity. Previous research has investigated the influence of hydrothermal conditions on the mechanical properties of pure PA 6. This study aims to extend the preceding investigations with additional experimental tests. As a preliminary work to later investigate the influence of the fibers on the hydrothermal behavior, discontinuous long carbon fiber‐reinforced PA 6 is considered for micromechanical modeling of the effective behavior. In this context, a mean‐field homogenization approach based on the Hashin–Shtrikman principle is used. By means of a variable reference stiffness, an approach specifically tailored to the material system under consideration can be applied. The simulation data are compared with data from experiments under tension load indicating good agreements for a specific choice of the reference material.