Mechanical Behavior and Failure Analysis of Additively Manufactured Cellular Structures and Architected Materials

In recent years, cellular solids and architected materials have garnered increasing attention, thanks to their superior mechanical performance. This allows scientists nowadays to explore new regions in the material property space, paving the pathway to a revolution in most of engineering disciplines. This thesis opens with an exploration on the mechanical behavior of novel multi-phase cellular structures in quasi-static and dynamic conditions: experiments and simulations on foam- and shear-thickening-fluid-filled cellular structures are performed in parallel, to analyze the influence and the interaction between each constituent material on the global composite structure’s properties. The wide spread of cellular structures is supported by the impressive advancements in additive manufacturing technologies, now able to fabricate structures with such complex geometries, otherwise impossible to obtain with traditional manufacturing processes. Following this, a further study on the failure mechanism of cellular structures and on the effect of the 3D-printing process on the mechanical properties of the material in safe and damage regimes is required. A multi-scale approach and a directional damage model, both based on microscopy analysis, are proposed to model parts produced via material extrusion and are validated against experimental tests, correctly predicting their predominant deformation and failure mechanisms. Moving the attention to the unprecedented potential of architected materials, focus is set on kirigami meta-materials. By harnessing the mechanics of a bi-stable truss, studied via analytical and experimental approaches, a new design methodology for multi-stable kirigami meta-materials is proposed, extending the kirigami world to aperiodic and potentially arbitrary geometries.