Rate-Dependent Shear Response during Off-Axis Loading of Fiber and Film-Based UHMWPE Composites

Author(s):

C Allan Gunnarsson, Stephen L Alexander, and Tusit Weerasooriya

Abstract:

A novel experimental method was developed to characterize the interlaminar shear response of ultra-high-molecular-weight polyethylene (UHMWPE) composites as a function of loading rate from low to high rate. Shear failure was induced by loading specimens at different off-axis angles relative to the plane of the unidirectional layers. The method was applied to two different classes of UHMWPE materials: Dyneema HB25 consisting of traditional SK76 fiber-based plies and the newer film-based Tensylon HSBD-30A. The method allowed for full-field deformation of the specimen surface to be recorded during loading, enabling the use of digital image correlation postprocessing to obtain contours of the evolution of maximum shear strain. Specimens showed increasing stiffness and strength with loading rate. Increasing the loading rate also induced a change in failure mode from ductile failure at slower rates to early localized shear failure at high rates. These experimental findings addressed a critical knowledge gap and have been used to iteratively develop rate-dependent computational models, encompassing shearing between plies and localized Mode-2 shear de-cohesion, that simulate UHMWPE rate-dependent loading.