Fatigue performance of laser cut carbon fiber-reinforced epoxy and polyamide 6 considering specimen width

Abstract

Since the development of laser systems technology led to a significantly decreased energy input by pulsing, laser cutting became a noteworthy method for cutting fiber-reinforced polymers. Despite the occurrence of heat introduction and heat-affected zones (HAZ), there are advantages regarding processing speed and maneuverability. Within this work, the influence of two cutting parameters (low (A) and high heat introduction (B)) on the fatigue properties of carbon fiber–reinforced epoxy and polyamide 6 were investigated. At the same time, micro waterjet cut specimens were added as a reference. In doing so, laminates were cut to different specimen widths and orientations. Multiple amplitude tests were performed with strain and temperature measurements. The results show an influence of specimen width on fatigue lifetime for the epoxy system, but not in polyamide 6. The 45° specimens for both CFR-EP and CFR-PA6 showed a decreased lifetime when cut with parameters B. However, these findings do not apply to 0° specimens, since parameters A lead to a smaller lifetime for CFR-EP, and no influence was found for CFR-PA6. Furthermore, no clear HAZ could be identified for A. Since there is a decrease in lifetime for CFR-EP, the necessity of applying further methods for HAZ detection is described.