Effect of cyclic loading and thermal stimuli on the shape memory behavior of PLA 3D-printed cellular structures

This study investigates the shape memory behaviour of PLA 3D printed cellular structures subjected to bending cycles. The focus is on their ability to recover the original shape following the application of a thermal stimulus. Both water and hot air were tested as activation media, with the structures subjected to three alternating cycles of stress and recovery to evaluate their performance. Two structural designs were considered: a topology with negative stiffness, modified to enhance performance and a structure inspired by the spring-loaded crossbow. The latter proved to be more effective, standing out for its mechanical strength and energy absorption capacity. The type of thermal stimulus significantly influences the recovery of the original shape. Specifically, the use of hot air enables localized recovery of the structure, reducing damage to the geometry as a result of cyclic stresses and increasing the energy absorption properties of the structure.