Application of the endochronic theory to model the mechanical behavior of short-fiber thermoplastics
Year: 2026
Type: article
Abstract: Models based on the flow theory of plasticity are widely used for modeling the mechanical behavior of thermoplastic composites under static and cyclic loading. These models are based on the introduction of a yield surface that separates elastic and inelastic deformation regions. However, experimental studies show that plastic behavior appears at the initial stages of loading, which makes identification of the yield surface position challenging. In the present work, the endochronic plasticity theory was employed to model the plastic behavior of composites reinforced with short glass fibers and based on polyphenylene sulfide and polypropylene matrices. The constitutive relations were presented in a general form with an extended set of parameters, enabling accurate modeling of composite behavior without invoking a yield surface. The material parameters were identified by minimizing the deviation function between calculated and experimental curves under uniaxial, off-axis, and shear loading. For the numerical implementation of the proposed approach, the method of successive approximations was used. The model was implemented into the ABAQUS solver using a user-defined UMAT subroutine. To validate the model, three-point bending simulations and fatigue modelling were performed. The results demonstrated good agreement with the experimental data. Several of the observed discrepancies could have been associated with scatter in thermoplastic properties.
Source: Results in Engineering
Institution: Skolkovo Institute of Science and Technology
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,940
OpenAlex ID: W7128679980