| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 7.02 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Esta dissertação teve como objetivo estudar o fenómeno de micropitting em engrenagens, utilizando simulações numéricas como substituto ao ensaio experimental, devido à avaria da máquina de ensaios FZG. Para isso, foram realizadas simulações com diferentes rugosidades e cargas, permitindo avaliar o comportamento das engrenagens sob condições variadas. Os métodos utilizados incluíram a caracterização detalhada dos corpos de prova, do óleo lubrificante e da textura superficial, além da implementação de um modelo numérico para a análise do micropitting desenvolvido por Romio et al. [1]. Os resultados das simulações mostraram que a rugosidade da superfície tem um impacto significativo na formação do micropitting, com o seu aumento a levar a uma maior probabilidade de ocorrência do fenómeno. A análise dos coeficientes de segurança à fadiga também indicou uma correlação direta entre o aumento da carga e a redução da segurança contra o micropitting, especialmente em superfícies com rugosidade elevada. Além disso, foi realizada uma comparação entre os valores dos coeficientes de segurança à fadiga obtidos nas
simulações numéricas e os obtidos no software KISSsoft, verificando-se uma boa concordância, embora o KISSsoft tenha mostrado uma linearidade na relação carga/segurança não observada nas simulações numéricas. As conclusões destacam a importância da rugosidade na ocorrência do micropitting e sugerem
trabalhos futuros para explorar a fronteira exata entre as rugosidades que causam e não causam micropitting, bem como a validação dos resultados simulados através de ensaios experimentais.
This dissertation aimed to study the phenomenon of micropitting in gears, using numerical simulations as a substitute for experimental tests due to the failure of the FZG testing machine. Simulations were conducted with varying roughness and load conditions, to assess gear performance under different scenarios. The methods used included detailed characterization of the test bodies, lubricant oil, and surface texture, in addition to the implementation of a numerical model for micropitting analysis developed by Romio et al. [1]. The simulation results showed that surface roughness has a significant impact on the formation of micropitting, with increased roughness leading to a higher probability of occurrence. The analysis of safety factors against fatigue also indicated a direct correlation between increased load and reduced safety against micropitting, especially on surfaces with higher roughness. Additionally, a comparison between the fatigue safety factors obtained from numerical simulations and those from the KISSsoft software revealed good agreement, although KISSsoft exhibited a linear load/safety relationship not observed in the numerical simulations. The conclusions highlight the importance of roughness in the occurrence of micropitting and suggest future work to explore the exact boundary between roughness that causes and does not cause micropitting, as well as the validation of simulated results through experimental tests.
This dissertation aimed to study the phenomenon of micropitting in gears, using numerical simulations as a substitute for experimental tests due to the failure of the FZG testing machine. Simulations were conducted with varying roughness and load conditions, to assess gear performance under different scenarios. The methods used included detailed characterization of the test bodies, lubricant oil, and surface texture, in addition to the implementation of a numerical model for micropitting analysis developed by Romio et al. [1]. The simulation results showed that surface roughness has a significant impact on the formation of micropitting, with increased roughness leading to a higher probability of occurrence. The analysis of safety factors against fatigue also indicated a direct correlation between increased load and reduced safety against micropitting, especially on surfaces with higher roughness. Additionally, a comparison between the fatigue safety factors obtained from numerical simulations and those from the KISSsoft software revealed good agreement, although KISSsoft exhibited a linear load/safety relationship not observed in the numerical simulations. The conclusions highlight the importance of roughness in the occurrence of micropitting and suggest future work to explore the exact boundary between roughness that causes and does not cause micropitting, as well as the validation of simulated results through experimental tests.
Description
Keywords
Micropitting Gears Roughness Lubrication Numerical simulation Safety factor Engrenagem Rugosidade Lubrificação Simulação numérica Coeficiente de segurança