Research into the Influence of Volume Fraction on the Bending Properties of Selected Thermoplastic Cellular Structures from a Mechanical and Energy Absorption Perspective

The aim of the manuscript is to study the effect of volume fraction on the bending properties of selected thermoplastic cellular structures (Primitive, Diamond, and Gyroid) from a mechanical and energy absorption perspective, with a view to their promising prospects and use not only for bumpers, but also for various vehicle and aircraft components, or other applications. Samples belonging to the group of so-called complex structures with Triply Periodic Minimal Surfaces, dimensions of 20 × 20 × 250 mm, and volume fractions of 30, 35, 40, 45, and 55%, were prepared by PTC Creo 10.0 software and produced using the Fused Filament Fabrication technique from Nylon CF12 material, while the basic cell size of 10 × 10 × 10 mm was maintained for all samples and the volume fraction was controlled by the wall thickness of the structure. Experimental bending tests were performed on a Zwick 1456 machine and based on recorded data; in addition to the maximum forces, the stiffness, yield strength, and effective modulus of elasticity in bending were evaluated for individual structures and volume fractions. Furthermore, the amount of energy absorbed until reaching the maximum force and until failure was compared, as well as the ductility indices <i>μ</i>_d and <i>μ_U</i> (derived from deformation and absorbed energy, respectively), as an important dissipation factor in absorbers, based on which it is also possible to predict which of the structures will have better damping.