Examinando por Autor "Salazar, A."

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Assessment of the viscoelasticity effects on the fracture resistance of polyacrylamide-alginate hydrogels
(Elsevier, 2025-05-13) Salazar, A.; Martínez, M.; Reinhards , C.; Rico, A.; Rodríguez, J.
Hydrogels are conditioned by viscoelasticity and poroelasticity. This work aims to assess the viscoelastic dissipation on the fracture parameters of polyacrylamide-alginate hydrogels applying the Viscoelastic Fracture Mechanics approach. The viscoelastic and poroelastic contributions were separated and quantified and the analysis of the characteristic times revealed that the poroelastic contribution could be disregarded. The fracture behaviour was obtained using the viscoelastic response once the poroelastic contribution was discounted from the mechanical relaxation response. The viscoelastic dissipation on the fracture parameters was not pronounced, with better fracture resistance the higher the alginate content. A linear relation has been observed between the J-integral and Crack Tip Opening Displacement through a cohesive stress with values similar to the tensile strength.
Fracture resistance of polyacrylamide-alginate hydrogels
(Elsevier, 2024) Reinhards-Hervás, C.; Cano, A.J.; Rico, A.; Salazar, A.; Rodríguez, J.
Polyacrylamide-alginate hydrogels are biphasic materials with double-polymeric structure and considerable percentage of water inside. They exhibit complex mechanical behaviour in which finite deformations, non-linearity and time dependence are mixed. Fracture behaviour is less known, and this work analyses the fracture resistance obtained via methodologies of non-linear elastic materials such as that developed by Rivlin and Thomas and that attained with Non-Linear Fracture Mechanics procedures based on the use of J-integral. Special attention is paid to the fracture parameters on both crack growth initiation and crack propagation stages. The validity of the methodologies was evaluated, and conclusions were drawn about the effect of the alginate content on the fracture resistance of polyacrylamide.
Structural integrity of polymers processed by additive manufacturing techniques using residual strength diagrams
(Elsevier, 2024-12) Cano, A.J.; Salazar, A.; Rodríguez, J.
Motivated by the increasingly important role that polymers have in structural applications, this study aims to analyse the structural integrity of polymers through residual strength diagrams. The polymers analysed have been thermoplastics, Polylactic acid (PLA), Polyethylene terephthalate glycol-modified (PET-G) and Polyamide 12 (PA-12), as well as a thermosetting resin, processed through different additive manufacturing techniques: Fused Deposition Modelling (FDM) in the case of PLA, PET-G, Selective Laser Sintering (SLS) for PA-12 and Digital Light Processing (DLP) for the thermosetting resin. In addition, PA-12 manufactured by injection moulding was also included in this study. To obtain the residual strength diagrams, mechanical tests have been carried out on smooth specimens and on specimens with cracks of different lengths. From the analysis of the results, a prediction has been obtained by fitting a semi-empirical model that describes the structural integrity in the areas of microstructurally short cracks, long cracks and physically short cracks