Evaluation of RST (Rapidly Solidified Technology) Structural Durability and Life Cycle Costs

摘要

The main objective of this study is to characterize the structural durability of high-strength powder metallurgy (P/M) aluminum alloys. The selected materials were CW67 extrusions, 7091-extrusions and 7091-forgings for P/M alloys and 2124-plate and 7475-plate for baseline materials. An F-16 aft fuselage bulkhead (FS446) was chosen as a prime configuration since a preliminary trade study predicted good weight savings from P/M alloys for this application. This also provides a good opportunity to study and compare two manufacturing technologies, machined plate vs. net shape forging. Therefore, test specimens were designed to model a critical location in the F-16 FS446 bulkhead. Spectrum fatigue tests were conducted under two types of spectrum load histories, HUD34 and NOR1. HUD 34 is a tension-compression type spectrum representing the 500-hour block spectrum for the F-16 FS446 bulkhead, while NOR1 is a tension-dominated type spectrum representing the B-1 wing carry-through box spectrum. Keywords: Equivalent initial flaw size, RST Structures, P/M Aluminum alloys, Spectrum loading, Fatigue, Time-to-Crack-Initiation, Crack growth, Initial fatigue quality, Reliability. (jes)