Analysis and Simulation of UHMW PE Fiber Reinforced Composites Subjected to Projectile Impact

Abstract

Ultra High Molecular Weight Polyethylene (UHMW PE) fibers –such as Dyneema and Spectra- are very strong and have a low density at the same time. UHMW PE fibers are used in ropes and in fiber reinforced composites (FRCs). UHMW PE fiber based FRC panels are used in projectile resistant applications and have a fiber volume content of over 80%. The objective of this research is to develop a simulation model that can predict the behavior (i.e. the most important fracture and failure phenomena) of UHMW PE based FRC panels that are subjected to projectile impact. This model can serve as an aid to further develop (UHMW PE based) FRCs with a high fiber volume content. Impact experiments, in which a projectile impacts on a UHMW PE based FRC panel, are used to determine the overall behavior of these panels using real-time monitoring and postimpact analysis. Directly after impact, the projectile takes some of the filaments with it . These filaments are stretched and some of them fail after some time. Some of these filaments slide away from the projectile, which is called filament sliding. In addition, delamination of the layers in the UHMW PE based FRC panel is seen. These three phenomena are considered most important and can be predicted by the simulation model. In the past, UHMW PE based FRC panels have mainly been modeled using continuum formulations. The drawback of a continuum model is that the modeling level is so crude that the phenomena described above cannot be realistically visualized. In this research, a meso model –the Lumped Filament Bundle approach- is developed that incorporates the aforementioned phenomena. The meso-model of a UHMW PE based FRC panel consists of continuum elements that are combined with rod elements. The rod elements represent a bundle of filaments and the remainder of the composite properties is described using continuum element. From preliminary results, it is found that using the Lumped Filament Bundle approach, filament fracture, filament sliding and delamination can be predicted. This indicates that this model can be used for development purposes of FRC panels with a high fiber volume content such as for UHMW PE based FRC panels.