Curing Deformation Prediction of Aircraft-Grade Toughened Composites Based on The Indirect Characterization Method

Accurate numerical simulation of curing deformation is essential for manufacturing high-quality thermoset carbon fiber composites. However, reliable material properties for constitutive modeling of aircraft-grade toughened prepregs remain challenging, primarily due to the extremely high viscosity of modified resin matrix, which hinders the preparation of low-porosity specimens critical for experimental characterization. To address this, we develop an indirect characterization method for resin’s curing characteristics using unidirectional composite prepreg as the test medium. Pure resin thermodynamic properties are derived from composite measurement data via reverse homogenization, enabling comprehensive evaluation of unidirectional composites with varying fiber volume fractions. The approach integrates the time-temperature superposition principle (TTSP) with Laplace-domain micromechanics, effectively circumventing complex viscoelastic convolution integrals in the constitutive model. Finally, a comprehensive material model of the composite material is integrated into a coupled constitutive model in Abaqus/Standard using a user-defined finite element analysis (FEA) subroutine, which considers the diversity of composite structure geometry, lamination sequence, and fiber volume fraction. Validation experiments on beam-shaped and L-shaped laminates show that the proposed method achieves a prediction accuracy of over 91.1% for curing-induced deformation, which is in good agreement with the finite element analysis results. This method not only provides a robust framework for characterizing and modeling high-viscosity resins and their composites but also enables efficient process optimization for complex composite components, thereby significantly reducing costly experimental expenses.