Browse Topic: Cutting
Hybrid additive manufacturing (AM) and subtractive manufacturing (SM) processes utilize the combination of AM (e.g., LPBF and DED) and SM (e.g., milling and turning operations) to produce the final part. Due to the poor surface roughness resulting from the uneven melting of powders in AM, the subtractive process is a necessary finishing operation to improve the surface roughness of the AM part. The hybrid AM/SM technology combines the benefits of AM and SM processes to create complex geometry while introducing good surface finish and compressive stress to prevent crack initiation. However, the relationship between large process parameter space and the residual stress/distortion in the part is not well understood, which impedes the adoption of hybrid AM/SM to minimize the residual stress in the final product. To expedite the process optimization, we establish a pipeline for the sequential modeling of additive manufacturing (AM) and subtractive manufacturing (SM) processes. Key
Prior to 1950, use of the helicopter for evacuation was extremely limited, as military top brass often considered it a worthless contraption; thus, rescue was uncertain at best for downed pilots and wounded soldiers stranded behind enemy lines. However, this all changed in Korea, where twelve U.S. Army helicopters from three detachments, working in tandem with seven, newly created Mobile Army Surgical Hospital (MASH) units, would fundamentally change the Army's medical-evacuation doctrine forever. Using several models of the Bell H-13, the Hiller H-23, and the Sikorsky H-5 and H-19, this small band of courageous pilots pushed themselves and their aircraft to their limits, transporting 21,212 critically wounded soldiers for life-saving surgery to various MASH units, cutting the fatality rate from World War II in half. Adopting the 3rd Air Rescue Squadron's motto, "That Others May Live," these pilots and their helicopters were affectionately known to the wounded as "Angels of Mercy."
The Army is pivoting to meet the challenges of a rapidly evolving threat environment in an increasingly complex world; this requires an agile and adaptive capability, leveraging competition, while operating within the constraints of current budget cycles. A cross cutting architectural approach provides opportunity for the Army to maintain capability overmatch. Recent changes in acquisition law and Army modernization strategy bring particularly strong emphasis on adoption of Modular Open Systems Approach (MOSA) and Open Systems Architecture (OSA). Many current programs within Army Aviation rely on a best effort approach ("Do MOSA") to deliver systems. Current programs measure success on cost, performance, and schedule of the individual program with little historical institutional support for aligning efforts across a larger "whole-system" context, such as a Combat Aviation Brigade (CAB). Specific programs, including the Utility Helicopter Program Office (UHPO) UH-60V and Crew Mission
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