Mechanical behavior of co-continuous polymer composites

Natural and synthetic composite materials consisting of two or more different materials are a major avenue for achieving materials with enhanced properties and combination of properties. The combination of hard and soft materials enables outstanding combination of mechanical performance properties including stiffness, strength, impact resistance, toughness, and energy dissipation. In this work, we demonstrate the potential to achieve materials with enhancements in stiffness, strength and energy dissipation. We consider co-continuous structures with simple cubic (SC), body-centered-cubic (BCC), and face-centered cubic (FCC) lattices, which are generated by 3D printing technology. The linear and nonlinear mechanical behavior of these composites including their elastic stiffness, yield, post-yield, and dissipative behaviors are investigated by compression tests. The experimental results are compared with finite element based micromechanical modeling of large elastic-viscoplastic deformation. We show that these 3D periodic cocontinuous composites can provide enhanced improvement in combinations of mechanical performance achieving a unique combination of stiffness, strength and energy absorption. These results provide guidelines for engineering and tailoring the nonlinear mechanical behavior and energy absorption of the composites for a wide range of applications.