Impact-Dissipating Capacity of Fiber-Reinforced Polymer Samples, Fabricated by Fused Filament Fabrication

The use of additive manufacturing for the fabrication of sacrificial cladding is becoming increasingly popular as it facilitates the production of complex yet space-saving protective structures. Despite this, the effect of several structural parameters on their capacity to mitigate high-velocity impacts remains elusive. Toward this end, the shock-mitigating capacity of various short fiber-reinforced polymer samples was evaluated regarding impact velocity and mass (raging from 1 to 8.3 m/s and 5.5 to 7.5 Kg, respectively). Among the assessed parameters were peak force (measured to vary by up to 46.6%), max. and mean deceleration values (with max. differences documented at 29.5% and 48.2%, respectively) and cushion factor. As expected, the progressive crushing modes differed significantly across the spectrum of the tested samples. Structural failure involved the growth of inter- and intra-laminar cracks, fiber-matrix de-bonding and de-lamination, which was dependent on equivalent pore volume fraction and compressive strength. Increasing infill density led in most cases to higher peak forces during impact, as did the deposition of more solid peripheral layers, with the latter producing a superior deceleration plateau. Evaluated collectively, the results indicate that an infill density of 37% with 4 solid external (protective) layers exhibited the superior impact response among the tested samples.