Thermal fatigue life of carbon nanotube wire and unidirectional carbon fiber/epoxy composite (UCFEC) in earth orbit

The most important target of this study is to develop a method to compare the materials’ degradation due to thermal fatigue and temperature variation between the carbon nanotube wire and unidirectional carbon fiber/epoxy composite (UCFEC). In the presented study, by using experimental results data, thermal fatigue life of carbon nanotube wire and unidirectional carbon fiber/epoxy was compared after being exposed to temperature variation in space. This process was done by using a new analytical method that models the material strength deterioration as a function of temperature variation in low Earth orbit thermal cycles. Based on the relations that were obtained by using recommended analytical method, the carbon nanotube wire offered less thermal fatigue strength degradation equal to 6.608% after being subjected to 1,200,000°C temperature variation in comparison with unidirectional carbon fiber/epoxy composite thermal fatigue strength degradation. Therefore, it seems that carbon nanotube wire shows better thermal fatigue resistance. The results of this comparison may be used to determine the suitable carbon material for space missions based on thermal fatigue life.   Key words: Carbon nanotube, low earth orbit, thermal cycles, temperature variation, material degradation.