TY - JOUR
T1 - Constitutive modelling of time-dependent polymer matrix composites
T2 - Incorporating a visco-hyperelastic model into the micromechanical framework
AU - Li, Wenlong
AU - Wu, Shiyu
AU - Zhu, Jianguo
AU - Zhang, Lili
AU - Zheng, Jing
AU - Wang, Haojing
AU - Qiu, Yaping
AU - Xie, Guihua
AU - Li, Cheng
N1 - Publisher Copyright:
© 2025 Elsevier Ltd
PY - 2025/8/15
Y1 - 2025/8/15
N2 - Accurately modelling the stress–strain response of carbon fiber reinforced polymer composites (CFRPs) at high strain rates remains challenging due to the nonlinear time-dependent behavior of the polymer matrix. In this work, we develop and validate a new micromechanics-based constitutive model that, for the first time, integrates a single-relaxing-component visco-hyperelastic formulation, also called internal state variable model, into the method of cells (MoC). To account for the effects of shear stress concentration at the fiber–matrix interface, a scaling parameter is introduced in the matrix overstress term. For brittle thermoset matrices, a degraded pseudo tensile yield stress is implemented to represent interface de-bonding during the early loading stage. To capture the pronounced nonlinear stress–strain characteristics of CFRPs, a monotonically increasing resistant stress term is employed in the matrix flow rule. The proposed model successfully predicts the off-axis tensile responses at various strain rates for three kinds of composites, including both thermoplastic and thermoset matrix composites, with carbon fiber moduli ranging from 200 GPa to 300 GPa. This favourable validation indicates that a more comprehensive visco-hyperelastic formulation with multiple relaxing components for the polymer matrix can be readily incorporated into the current framework, thus enabling accurate predictions for CFRPs at higher strain rates.
AB - Accurately modelling the stress–strain response of carbon fiber reinforced polymer composites (CFRPs) at high strain rates remains challenging due to the nonlinear time-dependent behavior of the polymer matrix. In this work, we develop and validate a new micromechanics-based constitutive model that, for the first time, integrates a single-relaxing-component visco-hyperelastic formulation, also called internal state variable model, into the method of cells (MoC). To account for the effects of shear stress concentration at the fiber–matrix interface, a scaling parameter is introduced in the matrix overstress term. For brittle thermoset matrices, a degraded pseudo tensile yield stress is implemented to represent interface de-bonding during the early loading stage. To capture the pronounced nonlinear stress–strain characteristics of CFRPs, a monotonically increasing resistant stress term is employed in the matrix flow rule. The proposed model successfully predicts the off-axis tensile responses at various strain rates for three kinds of composites, including both thermoplastic and thermoset matrix composites, with carbon fiber moduli ranging from 200 GPa to 300 GPa. This favourable validation indicates that a more comprehensive visco-hyperelastic formulation with multiple relaxing components for the polymer matrix can be readily incorporated into the current framework, thus enabling accurate predictions for CFRPs at higher strain rates.
KW - Hyperelastic
KW - Micromechanics
KW - Off-axis
KW - Polymer matrix composite
KW - Time-dependent
UR - http://www.scopus.com/inward/record.url?scp=105003992407&partnerID=8YFLogxK
U2 - 10.1016/j.compstruct.2025.119220
DO - 10.1016/j.compstruct.2025.119220
M3 - Journal article
AN - SCOPUS:105003992407
SN - 0263-8223
VL - 366
JO - Composite Structures
JF - Composite Structures
M1 - 119220
ER -