Browsing by Author "Polvorosa, Roberto"
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Item Effects of Ultrasonics-Assisted Face Milling on Surface Integrity and Fatigue Life of Ni-Alloy 718(2016-11-01) Suárez, Alfredo; Veiga, Fernando; de Lacalle, Luis N.López; Polvorosa, Roberto; Lutze, Steffen; Wretland, Anders; FABRIC_INTEL; Tecnalia Research & InnovationThis work investigates the effects of ultrasonic vibration-assisted milling on important aspects such us material surface integrity, tool wear, cutting forces and fatigue resistance. As an alternative to natural application of ultrasonic milling in brittle materials, in this study, ultrasonics have been applied to a difficult-to-cut material, Alloy 718, very common in high-temperature applications. Results show alterations in the sub-superficial part of the material which could influence fatigue resistance of the material, as it has been observed in a fatigue test campaign of specimens obtained with the application of ultrasonic milling in comparison with another batch obtained applying conventional milling. Tool wear pattern was found to be very similar for both milling technologies, concluding the study with the analysis of cutting forces, exhibiting certain improvement in case of the application of ultrasonic milling with a more stable evolution.Item Residual stress and distortion modeling on aeronautical aluminum alloy parts for machining sequence optimization(2020-09-01) Casuso, Mikel; Polvorosa, Roberto; Veiga, Fernando; Suárez, Alfredo; Lamikiz, Aitzol; FABRIC_INTEL; Tecnalia Research & InnovationThe manufacture of machined components for the aeronautics industry often involves the removal of large quantities of material, while the stringent demands on quality require special care to be taken during the manufacturing process. For most components of this kind, the principal source of distortion is the relaxation of residual stress after the earlier manufacturing processes. In this paper, the problem is addressed through modeling and simulating the final displacement fields obtained after different machining sequences of an aeronautic turbine component, in order to determine the optimum machining sequence among the options that lead to the same final part. Some of the main problems associated with this issue are also addressed, such as the high computational cost and time needed for simulations and expensive equipment needed for residual stress measurement. The level-set technique is employed, which decreases remeshing needs, while affordable nondestructive techniques for measuring residual stress are developed, providing qualitative information that is especially useful in industrial environments.