Numerical Simulation of the Frequency Dependence of Fatigue Failure for a Viscoelastic Medium Considering Internal Heat Generation.

Accurately predicting fatigue failure in CFRP laminates requires an understanding of the cyclic behavior of their resin matrix, which plays a crucial role in the materials' overall performance. This study focuses on the temperature elevation during the cyclic loadings of the resin, driven by inelastic deformations that increase the dissipated energy. At low loading frequencies, the dissipated energy is effectively released as heat, preventing significant temperature rise and maintaining a consistent, balanced thermal state. However, at higher frequencies, the rate of energy dissipation exceeds the system's ability to release heat, causing temperature accumulation and accelerating damage progression. To address this issue, the study incorporates non-recoverable strain into a fatigue simulation framework, enabling the accurate modeling of the temperature-dependent fatigue behavior. At 0.1 Hz, damage accumulates rapidly due to significant inelastic deformation per cycle. As the frequency increases to around 2 Hz, the number of cycles until failure rises, indicating reduced damage per cycle. Beyond 2 Hz, higher frequencies result in accelerated temperature rises and damage progression. These findings emphasize the strong link between the loading frequency, non-recoverable strain, and temperature elevation, providing a robust tool for analyzing resin behavior. This approach represents an advancement in simulating the fatigue behavior of resin across a range of frequencies, offering insights for more reliable fatigue life predictions.