Mechanical behavior modeling of self-reinforced polypropylene composites under varying temperatures

Aiming at the complex mechanical behavior of polypropylene self-reinforcing composites at different temperatures and the insufficient prediction accuracy of existing models, this study proposed an improved phenomenological constitutive model considering temperature dependence. The experimental results show that the strength of materials drops sharply at high temperatures ranging from 40 °C to 120 °C, while the stiffness and strength increase significantly at low temperatures ranging from −30 °C to 0 °C. Model verification shows that this model can accurately capture tensile, bending and shearing behaviors at different temperatures: the overall matching rate between the tensile curve and the experimental value reaches 98.5%, and the prediction deviation of shear performance at 20 °C is only 0.2 MPa, demonstrating excellent multi-stage temperature transition prediction ability. This research provides a reliable mechanical property prediction tool for the engineering application of this material under complex temperature conditions.