http://hdl.handle.net/10884/1270 Mon, 27 Apr 2026 15:44:48 GMT 2026-04-27T15:44:48Z http://hdl.handle.net/10884/1328 Title: Cost analysis of alternative automated technologies for composite parts production Authors: Soares, BAR; Henriques, E; Ribeiro, I; Freitas, M Abstract: Composite material usage in aircraft has been rising since the 1990s, with significant increases in manufacturing productivity and repeatability due to automation in the production of aeronautic parts made of composite materials, becoming a strong driver for widespread adoption of composites in this industry. Automated Tape Layup (ATL) and Automated Fibre Placement (AFP) are two of the most important automated manufacturing technologies within aeronautics composites, although their cost implications and economic comparison have not been widely studied. This paper presents an economic evaluation of ATL and AFP technologies. Using process-based cost models, the manufacturing process of a horizontal stabiliser is modelled, determining for each technology the associated consumption and use of resources and their implications towards the part final cost. Results show that ATL is less expensive than AFP, due to lower material costs, although with less material efficiency and slower cycle time. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10884/1328 2018-01-01T00:00:00Z http://hdl.handle.net/10884/1327 Title: A new risk prioritization model for failure mode and effects analysis Authors: Anes, V; Henriques, E; Freitas, M; Reis, L Abstract: Failure modes and effects analysis is a framework that has been widely used to improve reliability by prioritizing failures modes using the so‐called risk priority number. However, the risk priority number has some problems frequently pointed out in literature, namely its non‐injectivity, non‐surjectivity, and the impossibility to give weights to risk variables. Despite these disadvantages, the risk priority number continues to be widely used due to its higher simplicity when compared with other alternatives found in literature. In this paper, we propose a novel risk prioritization model to overcome the major drawbacks of the risk priority number. The model contains 2 functions, the risk isso surface function that prioritizes 3 risk variables considering their order of importance in a given risk scenario, and the risk prioritization index function which prioritizes 3 risk variables considering their weights. The novelty of the proposed model is its injectivity, surjectivity, and ease of use in failure modes prioritization. The performance of the proposed model was analyzed using some examples typically used to discuss the conventional risk priority number shortcomings. The model was applied to a case study and its performance correlated with other risk prioritization models. Results show that the failure modes prioritization reached with the proposed model agrees with the expectations made for the risk scenario. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10884/1327 2018-01-01T00:00:00Z