Energy absorption and deformation of Re-entrant Bi-material tubular metamaterials

作者：Yinchuan He, Hongyu Yang, Chi Zhang, Wenlong Liu, Li Wang, Tingting Wang, Guoxing Lu, Juntao Yu, Kwong Ming Tse · 发表于：International Journal of Mechanical Sciences · 年份：2026 · DOI：10.1016/j.ijmecsci.2026.111495 · 被引用次数：4 · 研究领域：Metamaterials and Metasurfaces Applications、Cellular and Composite Structures、Acoustic Wave Phenomena Research

• Dual-material additive manufacturing of PLA–TPU ensures stable, controllable deformation without cracking. • The novel metamaterial exhibits 90%, 88%, and 91% improvements in stiffness, total and specific energy absorption. • The novel metamaterial retains 60% energy and 98.9% height after cyclic compression. This study presents a novel bi-material re-entrant tubular (BRT) metamaterial fabricated via dual-material additive manufacturing, in which a rigid PLA core is encapsulated by a flexible TPU shell. This configuration effectively integrates the high stiffness of PLA with the elasticity of TPU, enabling a stable and controllable collapse process without cracking. The soft–hard coupling ensures efficient stress transfer and coordinated deformation, mitigating stress concentrations and preventing premature failure. Compared with single-material re-entrant tubular (RT) structures, the bi-material BRT metamaterial exhibits substantial mechanical enhancement, with stiffness, total energy absorption, and specific energy absorption increased by 90%, 88%, and 91%, respectively. Parametric analyses reveal that increasing the PLA core thickness significantly improves structural stiffness, plateau stress, and energy absorption capacity, with specific energy absorption enhanced by up to 67%. However, excessive PLA thickness may weaken interfacial adhesion and induce delamination or brittle fracture, highlighting the importance of optimal thickness matching between soft and rigid lay...