https://hdl.handle.net/10259/4505 2026-04-21T08:44:52Z 2026-04-21T08:44:52Z Verbeeten, Wilco M.H. Lorenzo Bañuelos, Miriam https://hdl.handle.net/10259/10672 2025-07-05T00:05:44Z 2025-09-01T00:00:00Z

Material extrusion additive manufacturing of Acrylonitrile-Butadiene-Styrene: Experiments and anisotropic model for the orientation angle Verbeeten, Wilco M.H.; Lorenzo Bañuelos, Miriam The yield stress as a function of both strain rate and orientation angle was measured for material extrusion additively manufactured (ME-AM) Acrylonitrile-Butadiene-Styrene (ABS). Unidirectional test specimens were extracted by waterjet-cutting at different orientation angles from ME-AM processed plates. By printing rectangular plates, a strand trajectory of constant length can be applied. Thus, the thermo-mechanical history of the material was as similar as possible across the plate. By determining an average sample porosity using Archimedes’ principle, yield stress values could be compensated for the voids present in ME-AM specimen. A time- and orientation-dependent model, which combines an Eyring flow rule with Hill anisotropy, was used to describe the yield stresses as a function of strain rate and orientation angle. The model uses a factorizable approach, i.e. both effects are decoupled, which simplifies the determination of model parameters. This anisotropic continuum-based viscoelastic Eyring-Hill model is able to adequately predict the complex experimental yield stress behavior, which is a challenging task. Scanning Electron Microscope fractography revealed macroscopically more ductile behavior due to failure in the strand direction. Macroscopically brittle behavior was related to inter-strand failure. The present study is an important step towards the prediction of structural integrity of ME-AM parts, as time- and orientation-dependency are also important in creep and fatigue behavior.

2025-09-01T00:00:00Z Santiago Herrera, Mario Igos, Elorri Alegre Calderón, Jesús Manuel Martel Martín, Sonia Barros García, Rocío https://hdl.handle.net/10259/9296 2024-06-21T00:05:31Z 2024-04-01T00:00:00Z

Ex-ante life cycle assessment of directed energy deposition based additive manufacturing: A comparative gearbox production case study Santiago Herrera, Mario; Igos, Elorri; Alegre Calderón, Jesús Manuel; Martel Martín, Sonia; Barros García, Rocío As new technologies emerge is necessary to assess if they can actually contribute to sustainable improvement of industrial processes. Life Cycle Assessment (LCA) is a valuable tool to determine environmental impacts and compare systems. However, this comparison raises challenges when they have different maturity. This paper performs ex-ante LCA of an additive manufacturing (AM) technology, based on a step-wise approach built with parametrized modelling, allowing fair comparison with its conventional counterpart, for the study case of a gearbox component. Results show that AM technology generates higher impacts than conventional manufacturing (CM) casting process, using baseline values. These impacts can be reduced by 94% with best operating performances from literature, with emissions from 4520 to 264 kg CO2 eq./kg piece, and non-significant difference with CM (demonstrated by Monte Carlo sampling). A 58% weight reduction is necessary for the AM process to improves its environmental sustainability. This research provides eco-design recommendations supporting decision making for further development of new technology.

2024-04-01T00:00:00Z Solaguren-Beascoa Fernández, Manuel https://hdl.handle.net/10259/9259 2024-06-15T00:05:25Z 2023-05-01T00:00:00Z

Evaluation of uncertainty in the measurement of the stress-optic coefficient Solaguren-Beascoa Fernández, Manuel In this study, a method for evaluating the uncertainty of stress-optic coefficient measurements of photoelastic materials on a uniaxial tension/compression specimen is presented. The same problem is also approached in other previously used methods, in which multiple data fitted with ordinary least squares are considered. However, only the repeatability contribution to uncertainty is considered in those other methods, which are therefore not consistent with the ISO–Guide to the expression of Uncertainty in Measurement. All possible contributions to uncertainty can be taken into account using the General Least Squares-Lagrange Multipliers (GLS-LM) method presented here. The application of the method is illustrated with an example, from which it can be seen that uncertainty has been underestimated in the other methods used to date. As well as the estimate of the stress-optic coefficient and its corresponding standard uncertainty, the method also provides a data consistency test and an outlier identification tool.

2023-05-01T00:00:00Z Peral, Luis Borja Ebrahimzadeh, P. Gutiérrez, Ana Gabriela Porras Fernández-Pariente, I. https://hdl.handle.net/10259/9257 2024-06-14T00:05:18Z 2023-03-01T00:00:00Z

Effect of tempering temperature and grain refinement induced by severe shot peening on the corrosion behavior of a low alloy steel Peral, Luis Borja; Ebrahimzadeh, P.; Gutiérrez, Ana Gabriela Porras; Fernández-Pariente, I. In this study, the effect of tempering temperature on the corrosion behavior of a low carbon steel (F1272) was analyzed by means of electrochemical tests: linear polarization resistance, potentyodinamic polarization and electrochemical impedance spectroscopy (EIS) in freely aerated 3.5% NaCl solution, at room temperature. The results show that corrosion resistance of the steel increases with elevating tempering temperature from 200 to 500 °C and finally, to 680 °C. Additionally, a severe shot peening (SSP) treatment was applied in the sample with the best corrosion behavior (TT680), in order to modify the grain structure. Results evidence that corrosion resistance of the TT680 sample decreases after the applied SSP treatment (10A and 5000% coverage). Corrosion behavior is discussed through the different microstructural singularities induced both the heat treatments and the SSP.

2023-03-01T00:00:00Z