Structural behavior of 3D-printed sandwich beams with strut-based lattice core: Experimental and numerical study

This study aims to introduce 10 strut-based topologies which have been used to study the three-point bending and compressive responses of the lattice-core sandwich beams. All printed samples have fabricated from ceramic resin via digital light processing (DLP) 3D technology. Besides, three experiments have been performed to investigate the effects of ultrasonic cleaning time, ultraviolet (UV) radiation time, and effects of the time interval between 3D printing and experimental test on the mechanical behavior of UV sensitive resin. Also, the mechanical properties have been studied (e.g., compression, tensile, and flexural properties). According to experimental data, Star and Diamond topologies had maximum flexural and compression strength about 458 N and 450 N, as well as Grid and Re-entrant Honeycomb structures had minimum flexural and compression strength almost 119 N and 162 N, respectively. To evaluate the experimental results, 10 topologies (4 structures for flexural and 6 structures for compressive testing) were simulated through finite element analysis (FEA). Then, the deflection values and mechanical behaviour of specimens were compared with each other. Experimental and FE results confirmed each other, completely. As a result, it was evident that some structures, such as Grid had a better response under compressive load while having the weakest response to three-point bending. Furthermore, the Octet-truss structure resisted much greater deflection. On the other hand, the results indicate that Star and Diamond structures have higher stiffness and they are the best choice in the sandwiches under compressive and bending . These significant findings illustrate that some of the structures studied may have the potential to be considered as alternatives to optimal structures in the 3D-printed sandwich panels.