Experimental study on the mechanical properties of CFRP/epoxy composite plates under seawater immersion

This study investigates the effects of seawater immersion at different temperatures on the degradation and viscoelastic behavior of carbon fiber-reinforced polymer (CFRP) composite plates. The present study investigated the effects of seawater immersion on the degradation of mechanical properties at 20 degrees C, 40 degrees C, and 60 degrees C of the carbon fiber reinforced polymer (CFRP) composite plates. The specimens were prepared by hand lay-up and cured under water for 7 days before immersion in artificial seawater for 6 months. Interlaminar shear strength (ILSS), tensile strength, and dynamic mechanical analysis (DMA) tests were performed periodically over a six-month exposure period, and scanning electron microscopy (SEM) was used to characterize aging damage and fracture morphology. The long-term shear behaviour of CFRP plates in seawater has been predicted using the Arrhenius theory. The results show that immersion in seawater significantly reduces ILSS, especially at higher temperatures and longer immersion times. However, the overall tensile properties of CFRP plates were not significantly affected. Dynamic mechanical analysis (DMA) revealed a decrease in the damping (tan delta), indicating a reduction of the fiber-matrix adhesion. The long-term life prediction showed that CFRP plates subjected to seawater immersion are susceptible to degradation, with a stable retention of interlaminar shear strength at 70% for the composite laminate.

Automated summary

This study examines the effects of seawater immersion at different temperatures on the degradation and viscoelastic behavior of carbon fiber-reinforced polymer (CFRP) composite plates. The results show that immersion in seawater significantly reduces the interlaminar shear strength (ILSS) of CFRP plates, particularly at higher temperatures and longer immersion times. However, the overall tensile properties are minimally affected. Dynamic mechanical analysis reveals a decrease in damping, indicating a reduction in fiber-matrix adhesion. Long-term life prediction suggests that CFRP plates subjected to seawater immersion are susceptible to degradation, with a stable retention of 70% of the interlaminar shear strength in the composite laminate.