H, CH-8092 Z ich, Switzerland Danish Technological Institute DTI, DK-2630 Taastrup, Denmark; [email protected] Mechanical Engineering Division, Frederick University, Nicosia CY-1036, Cyprus Frederick Investigation Center, Nicosia CY-1036, Cyprus Correspondence: [email protected]; Tel.: 357-2239-4360 (ext. 42115)Citation: Photiou, D.; Avraam, S.; Sillani, F.; Verga, F.; Jay, O.; Papadakis, L. Experimental and Numerical Evaluation of 3D Printed Polymer Tetra-Petal Auxetic Structures beneath Compression. Appl. Sci. 2021, 11, 10362. https://doi.org/10.3390/ app112110362 Academic Editor: Georgios E Stavroulakis Received: 7 October 2021 Accepted: 1 November 2021 Published: 4 NovemberAbstract: Auxetic structures possess a unfavorable Poisson ratio ( 0) because of this of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and effect resistance, at the same time as exceptional mechanical response benefits for applications in defense, biomedical, automotive, aerospace, sports, customer goods, and individual protective gear sectors. Using the advent of additive manufacturing, it has turn into probable to produce complicated shapes with auxetic properties, which couldn’t happen to be achievable with IEM-1460 custom synthesis standard manufacturing. Three-dimensional printing enables effortless and precise control of the geometry and material composition from the creation of desirable shapes, giving the opportunity to explore distinct geometric aspects of auxetic structures having a selection of unique supplies. This study investigated the geometrical and material combinations which can be jointly tailored to optimize the auxetic effects of 2D and 3D complicated structures by integrating style, modelling approaches, 3D printing, and mechanical testing. The simulation-driven style methodology permitted for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with diverse polymer supplies. Compression tests had been performed to characterize the auxetic behavior of your diverse program configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of = -0.6 for particular shape and material combinations, as a result providing assistance for preliminary finite element studies on unit cells. Lastly, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical functionality on the auxetic structures by implies of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis. Search phrases: auxetic structures; additive manufacturing; SLS; FDM; quasi-static compression testing; FEAPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.1. Introduction Several of the major structural benefits of sandwich composites will be the high stiffnessto-weight ratio and the high bending strength-to-weight ratio. The sandwich increases the flexural rigidity of structures with out adding substantial weight. The style and manufacturing of lightweight composite structures for protective purposes are of interest for both defense and civilian applications, including aircraft, sports, automotive, and consumer goods [1,2]. Sandwich structures demonstrate fascinating characteristics, which include high-energy Cholesteryl sulfate Endogenous Metabolite absorption capacity, high strength, and enhanced stability [3]. A regular sandwich panel consists of a low-density core, mainly i.
