Dana Mcgraw Dattelbaum

Additive manufacturing (AM) has provided a new paradigm of control not only on material microstructure but also on structural assembly. The promise of AM lies in tailoring properties through this exquisite microstructural and topological design and fabrication, and the possibility of “metamaterial” properties simply not possible through conventional manufacturing. Relevant to mechanical properties and dynamic performance, the application of AM has resulted in many examples in which control of deformation mechanics and structural instabilities has led to novel properties, such as high strength-to-weight ratios, tailored thermal management, and auxetic properties. This chapter will provide an overview of the dynamic behaviors of additively manufactured polymers and metals and provide a perspective on future directions in the area.

Significant progress has been made in the in situ and postmortem observations of the dynamic tensile failure and damage evolution of a range of polymers employing Taylor anvil and Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) loading. The classic Taylor anvil technique involves impacting a right-cylinder against a semi-infinite rigid anvil to access large compressive strains (>1) and high strain-rates (>1,000/s). The Dyn-Ten-Ext technique probes the tensile response of materials at large strains (>1) and high strain-rates (>1,000/s) by firing projectiles through a conical die. Depending on the extrusion ratios and velocities damage varies from bulk deformation with substantial internal damage, to a stable jet with finite particulation, to catastrophic fragmentation. Postmortem sectioning and X-ray computed tomography access mechanisms of internal damage inception and progression. In situ measurements of damage are made with the impact system for ultrafast synchrotron experiments (IMPULSE) using the advanced imaging and X-ray diffraction methods available at the Advanced Photon Source. The time resolved phase-contrast imaging elucidates the evolution of damage features during dynamic loading that is observed in post mortem sectioning and tomography.