Geometrical Scaling Effects in the Mechanical Properties of 3D-Printed Body-Centered Cubic (BCC) Lattice Structures

Abstract

This paper investigates size effects on the mechanical response of additively manufactured lattice structures based on a commercially available polylactic acid (PLA) polymer. Initial attention is focused on investigating geometrical effects in the mechanical properties of simple beams and cubes. Following this, a number of geometrically scaled lattice structures based on the body-centered cubic design were manufactured and tested in order to highlight size effects in their compression properties and failure modes. A finite element analysis was also conducted in order to compare the predicted modes of failure with those observed experimentally. Scaling effects were observed in the compression response of the PLA cubes, with the compression strength increasing by approximately 19% over the range of scale sizes investigated. Similar size-related effects were observed in the flexural samples, where a brittle mode of failure was observed at all scale sizes. Here, the flexural strength increased by approximately 18% when passing from the quarter size sample to its full-scale counterpart. Significant size effects were observed following the compression tests on the scaled lattice structures. Here, the compression strength increased by approximately 60% over the four sample sizes, in spite of the fact that similar failure modes were observed in all samples. Finally, reasonably good agreement was observed between the predicted failure modes and those observed experimentally. However, the FE models tended to over-estimate the mechanical properties of the lattice structures, probably as a result of the fact that the models were assumed to be defect free.

Multi-objective numerical optimization of 3D-printed polylactic acid bio-metamaterial based on topology, filling pattern, and infill density via fatigue lifetime and mass

“…While this approach allowed for the successful printing of the specimens, it is important to investigate the potential effects of scaling on the accuracy of the geometrical features and the resulting mechanical properties in future investigations. Previous studies demonstrated clear size effects on the mechanical response of additively manufactured lattice structures [ 60 ]. 3D printing was done with white-colored PLA filaments, which diameter was 1.75 mm, by the YouSu Company.…”

Solid Stress-Distribution-Oriented Design and Topology Optimization of 3D-Printed Heterogeneous Lattice Structures with Light Weight and High Specific Rigidity

“…To intuitively compare and evaluate the designed lattice structures, we constructed new index parameters using Equation ( 6). The relative bending stiffness and relative density can be expressed by Equation (7) and Equation (8), respectively. Then, the exponent in Equation ( 9) can be used to compare the flexural stiffness considering the relative density of the lattice structure.…”

“…Three-dimensional (3D) printing is always desirably employed to fabricate lattice structural components with lightweight targets [ 4 , 5 , 6 ]. Lattice structures with complex configurations constantly receive attention due to their performance advantages, including high specific stiffness or specific strength and promoted energy absorption capacity [ 7 , 8 ].…”

Compression performance and analytical model of hexagonal-core sandwich panels fabricated by 3D printed continuous carbon fiber-reinforced thermosetting epoxy composites

“…Cracks grow along the fibers in the interlayer direction and only a very small fraction of the fibers will fracture. In addition, it is important to note that defects in the 3D printing process can seriously affect the mechanical properties of the specimens [29]. Compared with the single-layer specimen, the printing path of the double-layer specimen is more complicated.…”

“…Moreover, complex parts with pentagonal and honeycomb structure were printed to verify their molding capabilities. Aziz et al [29] fabricated four different sizes of body-centered cubic lattice sandwich based on 3D printing. The experimental results showed that despite the similar failure modes observed in all samples, the compression strength increased by only 60% after four times the size.…”