Bio-inspired bimaterial composites patterned using three-dimensional printing

Abstract

Multi-material composite structures exhibit highly enhanced mechanical properties by mimicking natural hierarchical materials such as nacre, crocodiles, armadillos, and turtles. Such composites have been reported to overcome the limitations of a single material. Numerous studies have developed bio-inspired composites with improved mechanical properties by using the patterns of natural materials. However, optimization of the patterns and configurations has not been studied comprehensively thus far. In this study, nacre-like laminated composites are designed, fabricated, and tested both experimentally and numerically to explore their energy absorption capacity. Nacre-like patterns are made by employing the Voronoi diagram, and produced into three-dimensional (3D) specimens of the structures by use of a dual extrusion 3D printer with two different plastic materials. Three-point bending tests are conducted to evaluate the energy absorption capacity of the specimen, which is found to be 11% larger than that of a single plastic specimen. The nacre-like structures are modeled reflecting the experimentally determined material properties, and the three-point bending tests are simulated by the finite element method. The experiment and numerical results of the tests are in good agreement. Multi-material composites with the natural hierarchical patterns are very promising to provide enhancement in mechanical properties. However, the adhesion between different materials in 3D printing still needs to be improved to fully harness the potential for further development.