Investigation on shape recovery of3Dprinted honeycomb sandwich structure

Lightweight sandwich panels have been used in various industry sectors due to their unique properties as well as a high ratio of stiffness-to-weight and energy absorption. Three-dimensional (3D) printing process provides a unique opportunity to fabricate highly complex shapes of sandwich panels and also the application of smart materials, such as shape memory polymers, can create unique functionality for the 3D printed sandwich structure so that they can change their shape in response to external stimuli and give a new dimension to the printing process called four-dimensional (4D) printing. Polylactic acid is a biodegradable and compostable polymer with a good shape memory effect that can be printed easily with an inexpensive fused deposition modeling. This study investigated the effect of printing and activation parameters on the functionality, in particular shape recovery, of the deformed sandwich structure with honeycomb out-of-plane tailored core. The input parameters were the activation temperature, the nozzle temperature, and the printing velocity. The results showed that the optimum recovery ratio can be achieved using a higher activations and nozzle temperatures and lower printing speed.