Session: 13-12-01: Modeling of the Fracture, Failure, and Fatigue in Solids I

Paper Number: 166224

Fatigue Response of a New Active Link-Based Design of Re-Entrant Double-Arrowhead Auxetic 

Auxetic materials designed for sophisticated mechanical and aerospace structures have complex designs, and their fatigue response has not yet been well studied. The complexity in the design of metamaterials presents tunable mechanical properties for structures, allowing them to adapt to the demands of their environment. Auxetic metamaterials are favored for their enhanced Poisson’s ratio, indentation resistance, improved toughness, and shear modulus. Recently, the authors introduced active links to hybridized re-entrant double arrowhead cells to enhance local bending for energy absorption applications. The active links further improve the mechanical properties of auxetic structures in either stretch or bending dominant lattice structures. These complex auxetic lattice structures hold a promising future, but their fatigue response needs to be well understood before their widespread applications.

Literature shows numerous studies on the fatigue response of 2D auxetic structures using materials ranging from plastic composites to metal alloys. Advancements in 3D and 4D printing have allowed for the manufacturing of such complex structures with these materials. As a result, a noticeable trend in the fatigue response of auxetic materials has become more evident in recent literature. Even so, there is not enough background yet to solidify our understanding of the fatigue response of complex auxetic structures. The proposed research for ASME IMECE 2025 focuses on the fatigue response of a newly developed stretch-dominant auxetic topology with active links. Stretch-dominant auxetics have an excellent stiffness-to-weight ratio but poor ductility. The recently introduced system has extra stiffness due to new bracing and significantly improved ductility due to the rotation of a local link member without failure. Much of the research on auxetics has not yet been applied to physical structures, mainly due to a limited understanding of their fatigue response in demanding structural applications. Metamaterials provide various design methodologies that enable the construction of different lattice structures; however, their complex designs make it difficult to quantify their fatigue responses.

To better understand how the features of active links affect auxetic structures, the authors will employ both numerical and experimental approaches to examine the response of an active link design under fatigue loads with varying midrange and alternating stresses. The study will focus on the effects of local plasticity initiation and evolution on fatigue failure. Additionally, the researchers will investigate how Poisson's ratio evolves over fatigue cycles and utilize microscale SEM and macroscale DIC characterization techniques to examine material fatigue failure mechanisms and the macroscale behavior of Poisson's ratio.

Presenting Author: Jose Villegas Hernandez Arizona State University

Presenting Author Biography: Jose De Jesus Villegas Hernandez is an undergraduate student researcher in the mechanical and aerospace engineering program in the school of Engineering of Matter, Transport and Energy at Arizona State University. Jose is interested in continuum mechanics, numerical analysis, multifunctional materials, and adaptive structures. Jose has been working on metamaterials and auxetic structures for sensitive applications in space, aerospace, health, and energy industry. Jose is also interested to enhance his knowledge in materials and mechanics further in a prestigious doctoral program.

Authors:

Jose Villegas Hernandez Arizona State University
Eric Lee California Polytechnic State University
Masoud Yekani Fard California Polytechnic State University