Quasi-zero stiffness TPU interlayer for aluminium–polymer pipe-in-pipe systems: design, modeling and multifunctional performance

Abstract

An architected thermoplastic polyurethane (TPU) interlayer is proposed for aluminium pipe-in-pipe (PIP) systems to combine load-bearing capacity with vibration attenuation. The interlayer is designed to exhibit a quasi-zero stiffness (QZS) response through geometric deformation. Analytical models are developed to describe its quasi-static force–displacement response and dynamic displacement transmissibility. Finite element simulations and compression and vibration experiments are used to assess plateau force, plateau width, specific energy absorption (SEA), and vibration transmission. Parametric studies examine the influence of material properties and geometric parameters on these performance measures. The results indicate that parameter variations can increase the QZS plateau width by 200%–300% relative to the baseline configuration and modify the plateau force. Three representative configurations are experimentally evaluated to examine the predicted compression and vibration responses. Differences between numerical predictions and experimental measurements are discussed in relation to material behavior, manufacturing variability, and boundary conditions. The study characterizes the relationship between interlayer geometry, compressive response, and vibration transmission, providing a basis for further development of architected interlayers for tubular assemblies.