Effects of structural parameters and temperature on compressive behavior of 3D printed concave negative Poisson's ratio structures

Negative Poisson's Ratio Structure (NPRS) is a structure with special mechanical properties, high stiffness, strength and excellent energy absorption. This study investigates the compressive behavior of 3D-printed concave honeycomb structures fabricated from polyamide 12 (PA12) and glass fiber-reinforced polyamide (PA/GF). The influence of structural parameters, namely the internal concave angle, and ambient temperature on the mechanical properties of these structures was evaluated through uniaxial compression experiments. Experimental images were used to analyze the impact of elevated temperatures on the structural response under load. The results demonstrate that increasing the internal concave angle leads to a decrease in both compressive strength and energy absorption capacity. Temperature significantly affects the mechanical properties of the structures. Two distinct deformation modes were observed: layer damage and flexural instability deformation. While both structural parameters and temperature influenced the deformation mode, the material composition (PA12 versus PA/GF) did not significantly alter the deformation behavior.This research provides valuable insights for designing two-dimensional concave honeycomb structures with optimized structural parameters and offers guidance on predicting their mechanical performance at elevated temperatures.