Validação tribológica de biograxas sintetizadas comparadas com graxas minerais comerciais
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Data
2020-08-21
Autores
Slavec, Güido Alves
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A dependência atual e a possível escassez dos recursos de petróleo e gás natural no futuro são grandes preocupações mundiais. Óleos de base mineral são muito utilizados como lubrificantes em aplicações industriais. Devido à alta demanda e dependência da indústria destes lubrificantes, o desenvolvimento, a produção e o uso de bases alternativas tornaram-se uma estratégia de mercado. Os lubrificantes de base vegetal são provenientes de fontes renováveis, mais biodegradáveis, menos tóxicos e, em alguns casos, podem apresentar melhores performances (ter um alto potencial lubrificante) quando comparados aos lubrificantes minerais. O presente trabalho tem como objetivo analisar se através da integração de técnicas preditivas, tais como a análise de partículas de desgaste e o monitoramento dos sinais de vibração, é possível validar graxas de base vegetal (óleo de soja sintetizado) comparando-as com graxas de base mineral comercial. A metodologia consiste na utilização de um tribômetro instrumentado do tipo pin/ball-on-disk determinando-se, mediante o uso de ensaios experimentais e análise de propriedades dos materiais, os coeficientes de atrito, as temperaturas da superfície de contato, as quantificações de desgaste, bem como a concentração e a natureza das partículas ferromagnéticas presentes nas amostras, através de diferentes testes tribológicos. Além disso, com a aquisição dos sinais de vibrações, emprega-se um algoritmo de sistema imunológico artificial de seleção negativa, baseado em conceitos de Monitoramento de Integridade Estrutural (SHM), capaz de identificar e classificar estes sinais em falhas ou não-falhas. Entre as nove amostras de biograxas analisadas, a LGQ04, LGQ05 e LGQ07 (ambas com espessante de lítio) exibiram desempenhos tribológicos semelhantes às graxas minerais comerciais, enquanto que as biograxas LGQ01, LGQ02 e LGQ03 (ambas com espessante de sódio) apresentaram performances inferiores com relação às demais. No entanto, os resultados revelaram-se satisfatórios e provam que a metodologia experimental utilizada na validação das biograxas demonstrou-se eficaz e precisa.
The current dependence and possible scarcity of oil and natural gas resources in the future are major concerns throughout the world. Mineral-based oils are widely used as lubricants in industrial applications. Due to the high demand and industry dependence on these lubricants, the development, production, and use of alternative bases have become a market strategy. Vegetable-based lubricants come from renewable sources, more biodegradable, less toxic, and, in some cases, can perform better (have a high lubricating potential) when compared to mineral lubricants. The present work aims to analyze whether, through the integration of predictive techniques, such as the analysis of wear particles and the monitoring of vibration signals, it is possible to validate vegetable-based greases (synthesized soy oil) by comparing them with commercial mineral-based greases. The methodology consists of the use of an instrumented tribometer of the pin/ball-on-disk type, determining, with experimental tests and analysis of material properties, the friction coefficients, the contact surface temperatures, the wear quantifications, as well as the concentration and nature of the ferromagnetic particles present in the samples, through different tribological tests. Also, with the acquisition of vibration signals, an artificial immune system negative selection algorithm was used, based on Structural Health Monitoring (SHM) concepts, capable of identifying and classifying these signals into failures or non-failures. Among the nine samples of vegetable-based greases analyzed, the LGQ04, LGQ05, and LGQ07 (both with lithium thickeners) exhibited tribological performances similar to mineral-based greases, while the vegetable-based greases LGQ01, LGQ02, and LGQ03 (both with sodium thickeners) showed lower performance compared to the others samples. The results proved to be satisfactory and prove that the experimental methodology used in the validation of vegetable-based greases proved to be effective and accurate.
The current dependence and possible scarcity of oil and natural gas resources in the future are major concerns throughout the world. Mineral-based oils are widely used as lubricants in industrial applications. Due to the high demand and industry dependence on these lubricants, the development, production, and use of alternative bases have become a market strategy. Vegetable-based lubricants come from renewable sources, more biodegradable, less toxic, and, in some cases, can perform better (have a high lubricating potential) when compared to mineral lubricants. The present work aims to analyze whether, through the integration of predictive techniques, such as the analysis of wear particles and the monitoring of vibration signals, it is possible to validate vegetable-based greases (synthesized soy oil) by comparing them with commercial mineral-based greases. The methodology consists of the use of an instrumented tribometer of the pin/ball-on-disk type, determining, with experimental tests and analysis of material properties, the friction coefficients, the contact surface temperatures, the wear quantifications, as well as the concentration and nature of the ferromagnetic particles present in the samples, through different tribological tests. Also, with the acquisition of vibration signals, an artificial immune system negative selection algorithm was used, based on Structural Health Monitoring (SHM) concepts, capable of identifying and classifying these signals into failures or non-failures. Among the nine samples of vegetable-based greases analyzed, the LGQ04, LGQ05, and LGQ07 (both with lithium thickeners) exhibited tribological performances similar to mineral-based greases, while the vegetable-based greases LGQ01, LGQ02, and LGQ03 (both with sodium thickeners) showed lower performance compared to the others samples. The results proved to be satisfactory and prove that the experimental methodology used in the validation of vegetable-based greases proved to be effective and accurate.
Descrição
Palavras-chave
Análise de vibrações, Algoritmo de seleção negativa, Biograxa, Graxa mineral, Monitoramento de integridade estrutural, Tribologia, Vibration analysis, Negative selection algorithm, Vegetable-based grease, Mineral-based grease, Structural Health Monitoring, Tribology