Análise de dados de degradação para amostras sob diferentes condições de uso: Um estudo em rodas de trens: um estudo de caso em rodas de trens ferroviários

• Ano de defesa: 2011
• Autor(a) principal: Julio Cesar Ferreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Desgaste de rodas de trem; Modelos de efeitos mistos; Análise de degradação; Confiabilidade; Engenharia de produção
• Link de acesso: http://hdl.handle.net/1843/BUOS-8S4KSG

Traditionally, reliability assessment of devices has been based on life tests (LT) or accelerated life tests (ALT). However these approaches are not practical for high reliable devices which are not likely to fail in experiments of reasonable length. For those devices, LT or ALT will end up with a high censoring rate compromising the traditional estimation methods. An alternative approach is to monitor the devices for a period of time and assess their reliability from the changes in performance (degradation) observed during the experiment. In this article we present a model to evaluate the problem of train wheels degradation, which is related to failure modes of train derailments. We first identify the most significant working conditions affecting the wheels wear by using a nonlinear mixed effects model (NLME) where the log-rate of wear is a linear function of some working conditions such as side, truck and axle position. Next, we estimate the failure time distribution by working condition analytically. Point and interval estimates of reliability figures by working condition are also obtained. We compare the results of the analysis via NLME to the ones obtained by an approximate degradation analysis