Session: 13-02-02: Advances in the Mechanics of Architected Materials II

Paper Number: 166095

Numerical Simulations on Tunable Mechanical and Thermal Responses of Square Lattices via Patterned Imperfections 

Material imperfections, such as cracks, voids, and inclusions, are traditionally regarded as structural weaknesses that reduce load-bearing capacity and may lead to premature failure. However, recent research has demonstrated that intentionally introducing imperfections in a controlled manner can lead to improved mechanical performance and novel functional properties. This study investigates the effect of patterned imperfections in square lattices, revealing tunable mechanical and thermal responses that provide new design opportunities for advanced materials.

The proposed lattice design features systematically arranged imperfections that induce opposite chiral orientation trends in neighboring cross-units. These imperfections play a critical role in determining the mechanical response of the structure under external loading. Depending on the relative radius of the applied indenter, the lattice exhibits one of two distinct behaviors. When the indenter radius is large, the lattice tends to maintain its original shape, exhibiting higher stiffness and resisting deformation. In contrast, when the indenter radius is small, a pattern transition occurs, allowing the structure to undergo significant reconfiguration due to the chiral arrangement of imperfections. This tunable deformation mechanism enables precise control over the mechanical properties of the lattice, demonstrating that imperfections can be strategically used to enhance material performance rather than being treated as defects.

In addition to mechanical properties, this study also examines the thermal behavior of the lattice structure under constrained boundary conditions. It was found that the introduction of patterned imperfections allows the material to exhibit different thermal expansion responses depending on external constraints. Under certain boundary conditions, the structure undergoes isotropic thermal expansion, maintaining uniform deformation in all directions. However, in other cases, the material not only expands but also undergoes a pattern transformation due to the chirality of the imperfections. This dual response introduces new possibilities for designing materials with programmable thermal and mechanical behaviors, which could be valuable in applications requiring adaptive or multifunctional materials.

To validate these findings, finite element analysis (FEA) simulations were performed using ABAQUS. The FE results confirm that by carefully tuning the imperfection pattern and distribution, both mechanical and thermal responses can be tailored in a predictable manner. This research highlights a novel approach to material design, where imperfections are intentionally leveraged to achieve enhanced and adaptable performance.

The insights gained from this study have significant implications for the development of mechanical metamaterials, thermal-responsive materials, and reconfigurable structures. The ability to control both mechanical and thermal responses through imperfection-induced transformations opens up new possibilities for applications in aerospace, robotics, biomedical devices, and other advanced engineering fields. Furthermore, the computational framework established in this work provides a foundation for future studies aimed at optimizing imperfection patterns for specific functional requirements.

In summary, this research demonstrates that patterned imperfections in square lattices can be used as a powerful design tool to achieve tunable mechanical and thermal properties. By leveraging imperfection-induced chiral responses, the structural and thermal behavior of the lattice can be dynamically controlled, offering a new pathway for the development of next-generation functional materials.

Presenting Author: Siyao Liu Northeastern University

Presenting Author Biography: Siyao Liu is a Ph.D. candidate at Northeastern University, specializing in the design and mechanical characterization of metamaterials. Her research focuses on developing 3D-printed microarchitected structures with tunable mechanical responses. She has conducted research at Harvard University's Center for Nanoscale Systems, where she worked on nanoscale frictional metamaterials, microfabrication, and mechanical testing. Her work has been presented at academic conferences and is forthcoming in peer-reviewed publications.

Authors:

Siyao Liu Northeastern University
Yaning Li Northeastern University