Bending behaviors of 3D-printed Bi-material structure: Experimental study and finite element analysis

This paper investigates the bending behaviors of a bi-material structure (BMS) using both experimental and numerical methods The BMS is a composite material built by a 3D-printed, open-cellular brittle plaster structure filled with a silicone elastomer. The composition and configuration of the two materials determine the overall mechanical properties. Four-point bending test results show a non-linear elastic property, enhanced strength and toughness of BMS samples compared to either material phase alone. Such behavior is believed to be a result of delayed microcrack propagation in the brittle phase and a hardening effect of elastomer. In the numerical study, finite element analysis (FEA) is employed to verify these hypotheses. The FEA incorporates a brittle cracking material model for the plaster and a hyperelastic model for the silicone. The brittle cracking model enables the estimation of element degradation as a result of crack development and thus eliminates the need for the extremely refined mesh. Simulation result confirms the non-linear elastic transition and crack-induced material degradation and visualizes the silicone strengthening mechanism that can avoid rapid structural rupture.