Analysis of polyetheretherketone fatigue properties using dynamic modulus and hysteresis loss

The study is devoted to the staging of fatigue behavior of polyetheretherketone under load and displacement control mode. The paper demonstrates the application of dynamic modulus and hysteresis loss as informative parameters that are sensitive to internal phenomena occurring in the polymer. The used approach makes it possible to identify 3 stages associated with hardening and softening or change in the orientation of molecules and the appearance of defects. For a specimen tested under load control mode (low-cycle fatigue), the change in hysteresis loss was 20% in total, while in dynamic modulus 0.1%. For a specimen tested under displacement control mode (high-cycle fatigue), the changes amounted to 1.5% for hysteresis loss and 1.8% for the dynamic modulus.