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Os materiais compósitos poliméricos, devido às suas propriedades intrínsecas, têm vindo
a ser utilizados cada vez mais nas mais diversas áreas da engenharia. Neste sentido, é
expectável que a possibilidade de ocorrerem falhas também se torne cada vez maior.
Atualmente, o estudo da fadiga fretting em laminados compósitos poliméricos tem sido
pouco explorado e é cada vez mais importante devido a estes substituírem cada vez mais
os tradicionais materiais metálicos. Assim, este trabalho tem como objetivo analisar o
comportamento à fadiga fretting, com recurso a ensaios experimentais, de laminados
compósitos de aramida e laminados compósitos híbridos de aramida/carbono. O
trabalho experimental foi realizado no LIM (Laboratorio de Ingeniería Mecánica) do
DIMF (Departamento de Ingeniería Mecánica y Fabricación) da ETSI (Escuela Técnica
Superior de Ingeniería) da US (Universidad de Sevilla). Os ensaios de fadiga fretting
foram realizados nos compósitos com pontes de contacto cilíndrico de AISI 304, com
uma configuração de contacto cilindro-plano, e realizados numa máquina de ensaios
MTS 810 para diferentes níveis de carga, frequência constante (8 ????) e condições
ambiente. Verificou-se que para as cargas cíclicas mais elevadas o fretting não influencia
a vida útil do laminado. No entanto, o efeito do fretting intensifica-se à medida que a
tensão máxima diminui. Também se verificou que não existe uma influência significativa
na vida à fadiga para ambos os laminados na gama das cargas normais aplicadas (dos 6
aos 11 ????).
Polymeric composite materials, due to their intrinsic properties, have been increasingly used in various areas of engineering. In this sense, it is expected that the possibility of failure also becomes increasingly higher. Currently, the study of fretting fatigue in polymeric composite laminates has been little explored and it is increasingly important due to the fact that these are increasingly replacing the traditional metallic materials. Thus, this work aims to analyse the fretting fatigue behaviour, using experimental tests, of aramid composite laminates and aramid/carbon hybrid composite laminates. The experimental work was carried out at the LIM (Laboratorio de Ingeniería Mecánica) of the DIMF (Departamento de Ingeniería Mecánica y Fabricación) of the ETSI (Escuela Técnica Superior de Ingeniería) at the US (Universidad de Sevilla). The fretting fatigue tests were performed on the composites with cylindrical contact bridges of AISI 304, with a cylinder-plane contact configuration, and performed in an MTS 810 testing machine for different load levels, constant frequency (8 ????) and ambient conditions. It was found that for the highest cyclic loads, fretting does not influence the laminate life. However, the effect of fretting intensifies as the maximum stress decreases. It was also found that there is no significant influence on fatigue life for both laminates in the range of applied normal loads (from 6 to 11 ????).
Polymeric composite materials, due to their intrinsic properties, have been increasingly used in various areas of engineering. In this sense, it is expected that the possibility of failure also becomes increasingly higher. Currently, the study of fretting fatigue in polymeric composite laminates has been little explored and it is increasingly important due to the fact that these are increasingly replacing the traditional metallic materials. Thus, this work aims to analyse the fretting fatigue behaviour, using experimental tests, of aramid composite laminates and aramid/carbon hybrid composite laminates. The experimental work was carried out at the LIM (Laboratorio de Ingeniería Mecánica) of the DIMF (Departamento de Ingeniería Mecánica y Fabricación) of the ETSI (Escuela Técnica Superior de Ingeniería) at the US (Universidad de Sevilla). The fretting fatigue tests were performed on the composites with cylindrical contact bridges of AISI 304, with a cylinder-plane contact configuration, and performed in an MTS 810 testing machine for different load levels, constant frequency (8 ????) and ambient conditions. It was found that for the highest cyclic loads, fretting does not influence the laminate life. However, the effect of fretting intensifies as the maximum stress decreases. It was also found that there is no significant influence on fatigue life for both laminates in the range of applied normal loads (from 6 to 11 ????).
Descrição
Palavras-chave
Aramida Carbono Fadiga Fretting Hibridização Laminados Compósitos