INFLUENCE OF TIME-DEPENDENT DAMAGE ON CREEP OF MULTIDIRECTIONAL POLYMER COMPOSITE LAMINATES

摘要

A previous study by the authors, Birur et al. [1] focused on the time-dependent evolution of various damage modes under constant load and their impact on creep-rupture of multidirectional laminates of a polymer composite (Hexcel F263-7/T300). In this study, the influence of these damage modes on creep of multi-directional laminates was focused; specifically, the influence of time-dependent evolution of transverse crack density, in both [+-45] and [90] plies, on creep of [+-45/90_2]_S was studied and modeled. [90] plies were the first to crack followed by [+-45] plies. The creep time, during which the transverse crack density evolved only in the [90] plies, decreased with increase in test load and temperature. The compliance of the laminate increased with time due to viscoelastic deformation of the plies and increase in transverse crack density. Apparent creep compliance was defined to capture both effects and was experimentally deduced for all the plies of the laminate that developed damage with time. A model, based on lamination theory, was used along with these apparent creep compliances for the plies to predict the creep compliance of the [+-45/90_2]_S laminate. The model predictions compared well with experimental results within 3 percent error.