“A Computational and Experimental Approach to Solid-State Additive Manufacturing of Metal Waste by Direct Additive Recycling” by Dr. Paul Allison (SERDP Project WP18-1323)

Solid-state additive manufacturing and repair processes, such as Additive Friction Stir Deposition (AFSD), provide a rapid, flexible, and robust metal recycling option that may be applied to manufacture large-scale multi-material components and/or repair damaged structures (i.e., vehicles, armor systems, etc.) while remaining in-theatre and at the point-of-need, thus reducing the associated logistical challenges. This presentation summarizes an experimental and computational investigation on the solid-state processing of two waste streams: (1) manufacturing chips and (2) field-damaged stacked strips via AFSD. X-ray Computed Tomography (CT) analyses shows fully dense depositions while robust mechanical behavior is observed in large test articles. Furthermore, the in-depth experimental datasets characterizing microstructure, residual stresses, and mechanical performance are being used to develop multiscale computational models for predicting material performance. The fundamental understanding compiled on this study could serve as the groundwork to transition AFSD from a nascent AM technology to a potential in-field manufacturing and repair technique at forward operating bases (FOBs) and depots.

“Development of an Agile, Novel Expeditionary Battlefield Manufacturing Plant Using Recycled and Reclaimed Thermoplastic Materials” by Dr. Prabhat Krishnaswamy (SERDP Project WP18-1047)

This presentation discusses applied research that supports the development of innovative agile manufacturing plants for onsite fabrication of recycled thermoplastic products at FOBs. The proposed manufacturing plants are designed to be contained in 20-foot ISO containers for both shipment and operation. A Department of Defense (DoD) study of base camp waste confirmed that the single largest source of waste plastics is Polyethylene Terephthalate (PET) from water and other beverage bottles. This SERDP project conducted by Emc² and the U.S. Army Corps of Engineers to convert waste or reclaimed PET (rPET) into useful products is now in its final year of completion as of 2022. This webinar highlights the key results from the project, including the design of agile systems and trials for the following tasks: sorting and cleaning systems to convert PET water bottles into clean flake; conversion of clean rPET flake into filament for additive manufacturing at FOBs; material characterization of additive manufacturing parts including effect of additives on properties; mobile systems to convert larger volumes of rPET into dimensional lumber products at FOBs; and evaluation of technologies for converting mixed plastics waste into ‘construction’ type blocks.  

Dr. Paul G. Allison is the director of the Manufacturing at the Point-of-Need Center, and an associate professor in the mechanical engineering department at The University of Alabama. Dr. Allison is pioneering computational and experimental research on solid-state advanced manufacturing processes, and is involved in developing the fundamental understandings of the processing-structure-property-performance relations for a variety of material systems to support basic and applied research projects with industrial sponsors as well as the Army, Air Force, Deparment of Homeland Security, Department of Energy, Federal Highway Administration, Marine Corps, Navy, and National Aeronautics and Space Administration. Dr. Allison has co-authored over 100 journal articles, book chapters, technical reports and conference papers. He is active on multiple technical committees for Society of Experimental Mechanics (SEM) and Metals, & Materials Society (TMS), and serves as the American Society of Mechanical Engineers (ASME) Constitutive Equations technical committee Chair and SEM Dynamic Behavior of Materials Technical Committee Secretary. He received his doctoral degree in mechanical engineering from Mississippi State University.

Dr. Prabhat Krishnaswamy is the co-founder of Emc2, an engineering research and development consulting company focused on materials, structural integrity and reliability of complex systems. Prior to that, he was a senior scientist at Battelle Memorial Institute in the advanced materials department.  Dr. Krishnaswamy has conducted extensive research in both analytical and experimental areas of engineering mechanics, and is a renowned expert in the mechanical and failure behavior of plastics, composites, and bio-based materials, especially in structural -bearing applications. He has led both the technology development and worldwide standards activities in the area of recycled plastics and composite lumber. Dr. Krishnaswamy has served as the principal investigator of a SERDP project to convert recycled thermoplastics into useful products at FOBs. Dr. Krishnaswamy received his doctoral degree in mechanical engineering from the University of Washington, Seattle, WA.