Energy absorption and rebound behavior of 3D-printed TPU lattice structures

Unmanned aerial vehicles (UAVs) often encounter complex ground conditions during takeoff and landing, especially on unpaved surfaces such as snow, sand, grass, and slopes, as well as under extreme conditions like strong winds and dense fog. In these scenarios, the landing gear may experience significant impact loads and vibrations. If the structure fails to absorb energy effectively and rebound promptly, it may compromise airframe stability, onboard system reliability, and operational safety. To optimize the energy absorption–rebound performance of UAV landing gear, this study employed thermoplastic polyurethane (TPU 98 A) to design five homogeneous and gradient lattice structures with varying cell parameters, fabricated via fused deposition modeling (FDM). Quasi-static compression tests were conducted to investigate load–displacement behavior, energy absorption, and rebound performance. A multidimensional evaluation system was established based on total energy absorption (EA), specific energy absorption (SEA), hysteresis loop area (HLA), energy recovery ratio (ERR), residual displacement ratio (RDR), and stiffness degradation ratio (SDR), enabling an integrated assessment of energy absorption and rebound. Results demonstrate that TPU lattice structures achieve high energy absorption while maintaining excellent rebound performance and structural stability.