Abstract:

This study examines the viscoelastic-plastic behavior of thermoplastic resin poly-ether-ether-ketone (PEEK) under high temperature and strain rate conditions, highlighting its potential in aerospace applications due to its impact resistance. A dual-hardening constitutive model that combines physical and phenomenological approaches is developed to simulate the mechanical behavior of PEEK. The model explicitly incorporates its marked tension-compression asymmetry in plasticity and relaxation, along with thermal softening at high strain rates, enabling accurate predictions over a wide range of temperatures and strain rates with minimal parameters. This study establishes a comprehensive workflow from experimentation to finite element (FE) simulation for thermoplastic resins. Uniaxial tensile and compression tests (23 °C–180 °C, 0.002 29 s^-1–0.193 61 s^-1) and split Hopkinson pressure bar (SHPB) tests (1 094.08 s^-1–5 957.88 s^-1) are performed to capture stress-strain responses across various conditions, with small-scale specimens enhancing fracture strain measurement accuracy, and quantify the Taylor-Quinney factor of the PEEK material during the adiabatic heating process. The findings demonstrate that the proposed constitutive model effectively predicts yield points across different strain rates and temperatures, with parameters easily obtainable through simple experimental methods, enhancing its practical applications.

Key words: constitutive model, viscoelastic-plastic, poly-ether-ether-ketone (PEEK), uniaxial tension, split Hopkinson pressure bar (SHPB)