High-cycle random vibration fatigue behavior of CFRP composite thin plates.

• High-cycle random vibration fatigue performance of CFRP thin plates was studied. • Proposing entire high-cycle vibration fatigue experimental process and method. • The fatigue failure mechanisms is only partially similar to traditional fatigue tests. • Established and validated random vibration fatigue S-N curves. • FEM and experiment investigated the mechanisms of fatigue failure under vibration. This study presents an in-depth investigation into the fatigue performance of carbon fiber-reinforced polymer (CFRP) thin plate subjected to high-cycle random vibration loading. The cantilever beam method is employed to simulate vibration loads encountered in engineering applications. The experimental processes include exploratory experiment, pre-experiment, and formal experiment to ensure the accuracy and reliability of the test results. Findings indicate that the conventional S-N curve models are not well-suited for directly predicting fatigue in composite materials under random vibrational loading. In the case of narrow-band distribution, the Rayleigh distribution exhibits superior predictive accuracy compared to the Dirlik model. Moreover, scanning electron microscopy (SEM) was employed for a comprehensive morphological analysis of surface and lateral damage zones within the specimens. The investigation unveils that lower strain levels lead to minor fiber or interface movements and adjustments on the specimen surface, while higher strain levels result in visible surface cracks and interface delamination. Matrix cracking and delamination are also observed along the lateral sides of the specimens. The damage analysis provides insights into the progression of damage and failure mechanisms at varying strain levels. [ABSTRACT FROM AUTHOR]