Effects of Ageing on Tensile Strength of Flexible Unidirectional Composite Laminates for Body Armor
Amy E. Engelbrecht-Wiggans, Amanda L. Forster
Many body armors are made of on unidirectional (UD) laminates, constructed of thin layers of high-performance fibers held in place using binder resins and thin polymer films, with the fibers in each layer oriented parallel to each other. Armor is constructed by stacking such UD layers in different orientations, typically alternating 0 degree and 90 degree layers. Of interest is the long-term performance, and while some research has been done into the behavior of the fibers after ageing, very little has been done on the behavior of the binder resins. Thus, in order to accurately predict long term performance for armors constructed from UD laminates, a better understanding of the material property changes with ageing is necessary. This work presents tensile data for UD laminate specimens, characterizing the strain rate and size effect response of unaged material as well as presenting data from specimens that have been aged up to 20 weeks at 70 C and 76 % RH. The results show evidence of degradation in strength after ageing when tested at low stress rates, indicative of binder degradation, mirroring previous observations of delamination after ageing.
Annual Conference and Exposition on Experimental and Applied Mechanics
and Forster, A.
Effects of Ageing on Tensile Strength of Flexible Unidirectional Composite Laminates for Body Armor, Annual Conference and Exposition on Experimental and Applied Mechanics, Reno, NE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927438
(Accessed June 1, 2023)