Thermomechanical constitutive modeling of the Kirigami-inspired shape memory alloy

Abstract Shape memory alloys (SMAs) are unique materials capable of recovering predefined shapes through reversible phase transformations between austenite and martensite phases. This behavior enables SMAs to exhibit the shape memory effect and pseudoelasticity, allowing for the recovery of large strains and the generation of significant forces. These properties make SMAs highly desirable for applications in actuation, sensing, and other engineering domains. Conventional SMA actuator designs, while effective, often face limitations such as slow response times, non-uniform stress distribution, and reduced fatigue life under cyclic loading. Integrating Kirigami-inspired techniques into SMA actuator design addresses these challenges by introducing precise cut patterns that transform 2D SMA materials into complex 3D structures. Kirigami-based SMA structures offer enhanced stroke lengths, improved heat dissipation, and uniform load distribution, reducing stress concentrations and extending the actuator lifespan. This approach enables the creation of versatile and efficient actuators with tailored mechanical properties, overcoming traditional design constraints. This paper presents a constitutive model for Kirigami-based SMA structures, coupling mechanical deformation and thermal response modeling to capture in-plane and out-of-plane deformations. The proposed framework provides a detailed understanding of the unique thermomechanical behavior of Kirigami-inspired SMA actuators, offering insights into their performance under varying operational conditions. The findings highlight the potential of Kirigami-based SMA structures for advancing actuator technologies across a range of applications.