Analysis and Simulation of the Compressive Strength of Bioinspired Lightweight Structures Manufactured by a Stereolithography 3D Printer.

The use of metamaterials is a good alternative when looking for structures that can withstand compression forces without increasing their weight. In this sense, using nature as a reference can be an appropriate option to design this type of material. Therefore, in this work, a comparative study of a selection of eight representative models of a wide variety of existing solutions, both bioinspired and proposed by various researchers, is presented. These models have been manufactured using stereolithography (SLA) printing, which allows complex geometries to be obtained in a simple way that would be more complicated to achieve by other procedures. Additionally, the manufacturing cost of each model has been determined. The compression tests of the different models have made it possible to evaluate the breaking force and its corresponding deformation. Likewise, a finite element analysis of the manufactured models has been carried out to simulate their behavior under compression, achieving results very similar to those obtained in the experimental tests. In this way, it has been concluded that, among the three-dimensional patterns, the structure called "3D auxetic" is the one that supports the greatest breaking force due to the topographic characteristics of its bar structure. Similarly, among the two-dimensional patterns, the structure called "Auxetic 1", with a topography based on curves, is capable of supporting the greatest deformation in the compression direction before breaking. Moreover, the highest resistance-force-to-cost ratio has been obtained with a "3D auxetic" structure.