Loading–Unloading Cycles of Three-Dimensional-Printed Built Bimaterial Structures With Ceramic and Elastomer

Abstract

This paper studies the loading–unloading behaviors of a three-dimensional (3D)-printing built bimaterial structure consisting of an open-cellular plaster frame filled with silicone. The combination of the plaster (ceramic phase) and silicone (elastomer phase) is hypothesized to possess a nonlinearly elastic property and a better ductility. Four-point bending tests with programmed cycles of preceding deformations were conducted. The results show that there exists a linear–nonlinear transition when the bending deflection is around 2 mm in the first cycle bending. As the cycle proceeds, this linear–nonlinear transition is found at the maximum deflection of the previous cycle; meanwhile, the bending stiffness degrades. It is believed that the occurrence of microcracks inside the plaster frame is the mechanism behind the phenomenon. The silicone provides a strong network suppressing the abrupt crack propagation in a brittle material. The effects of the frame structure and plaster–silicone ratio were also compared. A high plaster content and large cell size tend to have a higher stiffness and obvious linear to nonlinear transition while it also has more significant stiffness degradation.