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Matrix and Confinement Influence on the Dynamic Behavior of Fiberglass



Woven polymer matrix composites (woven PMCs) have the potential to offer mechanical and multifunctional improvements over traditional engineering materials. At the same time, the complex interplay between the fiber-matrix architecture during dynamic loading is not fully understood, and thus cannot be optimized for damageresistance in design. The focus of this work is to aid in understanding the role of the thermosetting matrix, and the influence of bounday conditions on damage mechanisms under acceleration-driven and high strain-rate loading events. To do so, we investigate two types of commercially available woven glass cloth composites with varying thermosetting resins under the conditions of dynamic compression at uniform high strain rate, and high-speed impact. The fiberglass variants of interest include commercially available Garolite (plain-weave) of either epoxy or melamine resin. Results indicate that under dynamic compression at nominally uniform strain rate, both types of composites exhibit an increase in strength over equivalent quasi-static loading conditions when unconfined, but can either increase or decrease compressive strength by adding bi-axial confinement, dictated by the orientation of the weave and ply layup with respect to the load when confined. Additionally, 0.8 mm thick fiberglass sheets impacted between 1 to 1.5 km/s with a 1.6 mm diameter nylon 6/6 sphere resulted in the melamine resin composite damage zone twice the size of the epoxy, with epoxy reaching its ballistic limit more readily than the melamine variant. It is suggested that the melamine matrix fiberglass composite acts more like a net, stretching out the damage over a larger area as the matrix breaks away from the weave, freeing the fibers to stretch during inelastic deformation and attenuating overall perforation.


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