Effect of operating temperature on the mechanical behavior of 3D printed continuous carbon fiber reinforced PEEK composites for space environments

Abstract

Continuous carbon fiber reinforced polyetheretherketone (PEEK) composites produced via material extrusion additive manufacturing (AM-CCF/PEEK) are emerging as next-generation materials in aerospace applications. For space-related uses, the elastoplastic damage behaviors of AM-CCF/PEEK composites under various operating temperatures are investigated experimentally and numerically. The stress–strain relationships and failure modes of AM-CCF/PEEK composites fabricated with the optimal process parameters are explored under longitudinal tension, longitudinal compression, transverse tension, transverse compression, and shear at temperatures ranging from 23 to 230°C. The longitudinal tensile strength at 230°C remains at 83.1% of the value at room temperature, while significant degradation is observed at 230°C under other loading conditions. Furthermore, distinct trends are noted in the temperature effects below and above the transition temperature of PEEK. Based on this, a meso-scale thermal constitutive model for AM-CCF/PEEK composites is developed using the temperature-dependent Liu-Huang-Stout yield criterion, the temperature-dependent maximum stress failure criterion, and a Kriging-based surrogate model. Coupled with a meso-scale finite element analysis (FEA) model, the orthotropic thermal elastoplastic damage behaviors of AM-CCF/PEEK composites are accurately reproduced. Highlights: The elastoplastic damage behaviors of AM-CCF/PEEK composites are evaluated. The effect of operating temperature is analyzed for different loading conditions. Good longitudinal tensile behavior is achieved at high temperature. Obvious degradation is found in all loadings except for longitudinal tension. A meso-scale thermal constitutive model for AM-CCF/PEEK composites is developed.