Mechanical Behavior at High Strain Rates and Impact of Polylactide (PLA)

Polylactide (PLA) is a biodegradable and bioactive thermoplastic polymer made from renewable resources. In recent years, it has become a popular material for use in additive manufacturing due to its ease of processing, excellent print quality, and environmentally friendly properties. The low density and energy dissipation during deformation makes this polymer attractive for ballistic applications. In this work, the mechanical response and fracture behavior of 3D printed PLA, considering printing process parameters and directionality, has been characterized at high strain rates with tensile split Hopkinson pressure bar, at higher strain rates and large strain under hydrostatic tension with the dynamic-tensile-extrusion (DTE) test, and at large strain and high strain-rate deformation, but under hydrostatic compression, with Taylor impact test. Successively, the high-velocity impact resistance of carbon nanotube-inspired 3D-printed lattice structures, designed to promote shearing and impact energy dissipation, has been investigated. The results of the experimental campaign are presented.