Compressive response of concave negative Poisson’s ratio cylindrical shell/TPMS core composite structures

Abstract

Conventional concave cylindrical shells, though lightweight, are prone to early failure under compression due to instability, limiting their energy absorption potential. This study introduces a hybrid shell–core design by integrating three types of concave shells with a Gyroid-based triply periodic minimal surfaces (TPMS) core to form a hierarchical structure that enhances both compressive stability and energy dissipation. Compression tests were conducted to examine mechanical performance and deformation behavior. Results show that alternating positive–negative units (NAP) consist of alternating positive and negative Poisson’s ratio units. Their peak load is ∼ 16 % higher than negative Poisson’s ratio units (NPR) and ∼ 60 % higher than positive ones (PPR), though specific energy absorption (SEA) is reduced.With TPMS integration, the NPR-based composite achieves 47 % improvement in both peak load and SEA, while the NAP composite attains a 63 % SEA increase. The failure modes of the three types of composite structures were different, with the PPR structure producing a peeling of the inner core and outer shell during failure, the NPR structure fracturing due to the extrusion of the inner and outer structures, and the NAP structure maintaining high loads due to the coupling of the first two deformations. This work demonstrates the effectiveness of shell-core synergistic mechanisms in optimizing structural properties and opens new avenues for designing lightweight, impact-resistant protective metamaterials in fields such as aerospace and automotive engineering.