Multiaxial fatigue behavior of thermoplastics including mean stress and notch effects: Experiments and modeling

•Experimental investigation of multiaxial fatigue of thermoplastics.•Influences of mean stress and stress concentration.•Damage mechanism, multiaxial damage modeling, and life predictions. Thermoplastics are used in many industries with many applications and can be manufactured using different processing techniques. Multiaxial loading and non-proportionality between different loading sources are inevitable in many design applications with such materials. In this study, multiaxial fatigue behavior of extruded high density polyethylene (HDPE), polypropylene (PP), and neat polyamide66 (PA66) as well as reinforced with short glass fibers (PA66-G30) was investigated. The effects of mean stress and stress concentration on multiaxial fatigue behavior were also studied. Analytical models to account for these effects based on observed damage mechanism are presented and discussed by the comparing with the experimental data.