WAVE PROPAGATION AND REGULATION IN PERIODIC STRUCTURE BASED ON 4D-PRINTING

In this paper, we analyze the propagation of elastic waves in thermo-responsive shape memory polymer periodic cellular structures. At first, the shape memory polymer (SMP) periodic structures based on tBA-co-PEGDA networks were photo-polymer printing by stereolithography apparatus (SLA). Due to the thermo-induced shape memory behavior, elastic instabilities of the internal microstructure for SMP can be triggered, thus causing a reversible change from square voids to circular voids. The temporary pattern transformations of the structures lead to a significant change in the phononic band structure, specifically in opening of a new narrow band gap. Besides, we also examined the evolution of their spectral band-gaps with varying volume fractions of the voids. The work provides good insights into structural organization and opportunities for developing tunable phononic devices.