Design of an auxetic cellular structure with different elastic properties in its three orthogonal directions

Abstract

Auxetic structures have become one of the most studied types of cellular structure in recent years, thanks to their highly specific mechanical properties. Most microstructures are designed with homogeneous properties in their main axes; however, in this research, we propose an innovative asymmetric 3D auxetic structure based on a 2D configuration of cells drawn from the literature. The new auxetic cell is designed by topology analysis using classical Timoshenko beam theory. To validate the design, samples were constructed by fused filament fabrication with ABSplus, and tested under quasi-static compression to determine Young's modulus in the three orthogonal directions. The experimental results show good agreement with the topological analysis and reveal that the proposed cell can transmit a different mechanical behavior to the macrostructure in its three orthogonal directions.

Evaluation of the Orthotropic Behavior in an Auxetic Structure Based on a Novel Design Parameter of a Square Cell with Re-Entrant Struts

“…Therefore, it is possible to model its mechanical behavior through the classical Timoshenko beam theory [ 33 , 38 , 49 , 53 ], according to the decomposition shown in Figure 2 . However, it has been shown in previous works [ 64 , 65 ] that Timoshenko’s simplified analysis successfully predicts the mechanical behavior of an auxetic structure with an asymmetric design. Therefore, neither the shear strain nor the axial strain of the horizontal elements and will be considered for this analysis since they are considered negligible.…”

“…The raw material of the filament is ABSplus. The Young’s modulus of the raw material processed by FDM denoted as , has been characterized in previous works for each manufacturing direction [ 64 , 65 ]. As is known, due to the layer-by-layer manufacturing process, an intrinsic anisotropy is introduced into the structure.…”

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

“…On one hand, the structures with a two-dimensional pattern (2D) developed by repeating the unit cells along with the two principal in-plane directions and then extruding in a third direction [40]. On the other hand, the structures with a three-dimensional pattern (3D) are designed by repeating the unit cells along with the three principal directions [41]. The following is an explanation of each of the 8 models divided into 2D and 3D patterns:…”

Enhancing Mechanical Properties of PLA and PP Composites through Ionic Zeolite with copper nanoparticles Reinforcement: Microstructural and Micromechanical Characterization

“…Though, they emphasize that opportunities lie in the customization of medical devices and implants to t each patient, reduced production times, and lower costs compared to traditional manufacturing methods. Additionally, 3D printing has the signi cant capability to create complex geometries and mechanically e cient structures that are di cult to achieve with traditional methods [19][20][21][22][23]. Finally, this polymer-based manufacturing method provides signi cant versatility in implementing new and innovative treatments, with the potential to revolutionize the biomedical eld.…”