Bimaterial 3D printing and numerical analysis of bio-inspired composite structures under in-plane and transverse loadings

This work presents a novel design, additive manufacturing and modeling approach of three dimensional voronoi-based composite structures that closely mimic nacre's multilayer composite structure. The hierarchical structure of natural nacre is mimicked to produce multilayer composite laminates assembled from three dimensional polygonal tablets bonded with organic adhesives. Furthermore, various complex geometries of the nacreous shells observed from the nature, such as the dome-shaped structure, are developed into three dimensional designs. A novel mapping algorithm is developed to generate complex structures of nacre-like composites that are readily fabricated by unique dual-material 3D printing technology. Preliminary 3D-printed prototypes with complex shapes and material combinations are presented. A novel numerical model of the nacreous composite is proposed, which includes tablet cohesive bonds and interlaminate adhesive layers to mimic the soft organic polymer matrix. The nacreous model is validated against a natural nacre specimen under uniaxial loading. To exemplify a potential application, a scaled model of a nacre-mimetic composite made of Aluminum tablets and Vinylester adhesive is constructed and assessed against blast-induced impulsive loading. The performance of the nacre-like composite panel is investigated in terms of deformation and energy dissipation