Characterizing the stress relaxation behavior of unidirectional prepreg through a parallel fractional-order viscoelastic model

In the hot-stamp molding and hot diaphragm forming processes of composites, pressure significantly influences shaping quality. This study establishes a novel parallel fractional-order viscoelastic (PFOV) model with two Scott-Blair elements, achieving remarkable accuracy (R2 = 0.99) with fewer parameters. Unlike traditional models, it incorporates the force history of prepreg, providing a more precise representation of its mechanical response. Comparative analysis against established models underscores its superior ability to capture intricate stress relaxation behaviors. Notably, the model's reduced parameters enhance its physical interpretability, offering a significant advantage in simulating and predicting prepreg material compression behavior for diverse manufacturing processes.