Antico, F. C., Concha-Riedel, J., Valdivia, I., García Herrera, C., & Utrera, A. (2023). The fracture mechanical behavior of the interface between animal fibers, mortar, and earth matrices. A theoretical and experimental approach. Compos. B. Eng., 254, 110568.
Abstract: Theoretical-experimental research is presented to address the mechanics and failure mode of the interface between two matrices with brittle behavior, earth and mortar, and pig hair, an organic fiber that is a massive waste from the food industry worldwide. A comprehensive statistical analysis of the pull-out force is presented, accounting for the effect of fiber embedded length, diameter variability, and age of the matrices. Experimental results are contrasted with fracture-mechanics theories to describe its behavior in this matter. Results show that neither fiber length, variability of diameter, nor the age of the matrix influences the pull-out force of both matrices evaluated in this work. Our results show the brittle nature of these interfaces, which was also observed using a high-speed camera. The tensile load of the fibers was compared to the pull-out force, showing that these fibers always work within their elastic regime. This work contributes directly to the sustainable goals 9, 11, and 15 enacted by the United Nations in 2015, by contributing to the understanding of the fracture mechanics of a waste product used as reinforcement of construction matrices.
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Slane, J., Vivanco, J., Meyer, J., Ploeg, H. L., & Squire, M. (2014). Modification of acrylic bone cement with mesoporous silica nanoparticles: Effects on mechanical, fatigue and absorption properties. J. Mech. Behav. Biomed. Mater., 29, 451–461.
Abstract: Polymethyl methacrylate bone cement is the most common and successful method used to anchor orthopedic implants to bone, as evidenced by data from long-term national joint registries. Despite these successes, mechanical failure of the cement mantle can result in premature failure of an implant which has lead to the development of a variety of techniques aimed at enhancing the mechanical properties of the cement, such as the addition of particulate or fiber reinforcements. This technique however has not transitioned into clinical practice, likely due to problems relating to interfacial particle/matrix adhesion and high cement stiffness. Mesoporous silica nanoparticles (MSNs) are a class of materials that have received little attention as polymer reinforcements despite their potential ability to overcome these challenges. Therefore, the objective of the present study was to investigate the use of mesoporous silica nanoparticles (MSNs) as a reinforcement material within acrylic bone cement. Three different MSN loading ratios (0.5%, 2% and 5% (wt/wt)) were incorporated into a commercially available bone cement and the resulting impact on the cement's static mechanical properties, fatigue life and absorption/elution properties were quantified. The flexural modulus and compressive strength and modulus tended to increase with higher MSN concentration. Conversely, the flexural strength, fracture toughness and work to fracture all significantly decreased with increasing MSN content. The fatigue properties were found to be highly influenced by MSNs, with substantial detrimental effects seen with high MSN loadings. The incorporation of 5% MSNs significantly increased cement's hydration degree and elution percentage. The obtained results suggest that the interfacial adhesion strength between the nanoparticles and the polymer matrix was poor, leading to a decrease in the flexural and fatigue properties, or that adequate dispersion of the MSNs was not achieved. These findings could potentially be mitigated in future work by chemically modifying the mesoporous silica with functional groups. (C) 2013 Elsevier Ltd. All rights reserved.
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Vera, R., Araya, R., Garin, C., Ossandon, S., & Rojas, P. (2019). Study on the effect of atmospheric corrosion on mechanical properties with impact test: Carbon steel and Galvanized steel. Mater. Corros., 70(7), 1151–1161.
Abstract: The present work presents the behavior of carbon steel and galvanized steel against atmospheric corrosion after 3 years of exposure at seven locations around the region of Valparaiso, Chile. Results show a relation between corrosion rates and environmental and meteorological conditions, categorized as CX for the Quintero zone, and C3 and C2 in the remaining six zones. Corrosion rate behaviors and material toughness losses were modeled using power functions and neural networks, found to be a function of environmental exposure time. Losses were greater for carbon steel in coastal and industrial environments, reaching 70 to 80%. This effect was reduced in galvanized steel, not exceeding 15% over the same period of exposure. The relationship between corrosion rate and loss of toughness of both materials was modeled using neural networks.
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Vera, R., Valverde, B., Olave, E., Sanchez, R., Diaz-Gomez, A., Munoz, L., et al. (2023). Atmospheric corrosion and impact toughness of steels: Case study in steels with and without galvanizing, exposed for 3 years in Rapa Nui Island. Heliyon, 9(7), e17811.
Abstract: We studied atmospheric corrosion on Rapa Nui Island, using galvanized and non-galvanized SAE 1020 steel samples exposed on racks. We also added Charpy samples of both materials to directly determine the effect of corrosion rate on these materials' impact toughness. The results indicated a correlation between corrosion rate and toughness loss in the studied materials. In the corrosion study, we could also demonstrate the effect from increased insular population growth on con-taminants which aid atmospheric corrosivity. Results showed that atmospheric SO2 has tripled compared with similar corrosion studies done 20 years ago (Mapa Iberoamericano de Corrosi & PRIME;on, MICAT), increasing corrosion rates. Our results show how human factors can influence changes in environmental variables that strengthen corrosion.
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