An Experimental-Computational Framework for UHMWPE Films Based on Deformation and Failure Mechanisms: General Approach and Application to Off-Axis Shear Loading

Author(s):

Stephen L Alexander, Richard Becker, and Tusit Weerasooriya

Abstract:

Finite element simulation of ultra-high-molecular-weight polyethylene (UHMWPE) composites loaded under Army-relevant conditions remains a challenge. The problem is confounded when attempting to predict the response of novel film-based UHMWPE materials, for which there is a lack of data and fundamental understanding relative to traditional fiber-based systems that have been experimentally characterized extensively. Here, a computational framework for simulating the multiaxial and multirate response of UHMWPE films was developed at the subscale of individual UHMWPE layers. The concept was physics-based, directly modeling the governing deformation and failure mechanisms of the films. Plastic deformation of the layers was described with a crystal plasticity approach based on film mesostructure. Failure by delamination between layers was represented with Mode 2 traction-separation relationships dependent on loading rates. Parameter values for UHMWPE films were determined by simulating a unique set of off-axis shear loading experiments on film-based composites across loading rates from quasi-static to dynamic. As far we know, this is the first time that cohesive laws have been obtained and implemented based on actual experiments at multiple strain rates. In addition, the utility of the present subscale approach was demonstrated by transitioning to a higher-length-scale material model previously developed for fiber-based composites.