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An experimental design method is proposed to guide the selection of specimen dimension and split Hopkinson pressure bar apparatus. This method is applicable to the woven composite with modulus independent of strain rate. This method can predict the maximum specimen dimension at the desired strain rate under the maximum strike velocity of the apparatus. Based on the proposed design method, the in‐plane dynamic compressive behavior of 2D plain weave carbon/aramid hybrid composite was obtained. The strength exhibited sensitive to strain rates. The nonlinear constitutive model described the dynamic constitutive relationship effectively. The distribution of delamination failure significantly influenced the final failure shape of the specimens through the high‐velocity camera. Microscopic observations indicated that carbon fiber yarns and aramid fiber yarns exhibited different fracture modes. Highlights: An experimental design method applicable to woven composites in dynamic tests.Negative correlation between strength and strain rate of hybrid composites.The validity of the nonlinear constitutive model to dynamic property.The effect of hybridization and strain rates on damage modes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A biaxial TTF spectrum with different frequencies and amplitudes is designed. • A method of synchronized acquisition of DIC and testing machine is proposed. • Damage behavior of plain weave composites under biaxial TTF loads is investigated. • Fatigue lives decrease rapidly with increasing torsional fatigue loads. • Superimposed torsional fatigue loads mainly promote matrix cracking and debonding. In this paper, the fatigue life and damage mechanism of plain weave composites under biaxial tension–torsion combined fatigue loading (TTF) are experimentally investigated. A biaxial TTF loading spectrum is designed to consider different fatigue frequencies and amplitudes, and an automated multi-module loading method with synchronized acquisition of the digital image correlation (DIC) and the testing machine is proposed. A comprehensive analysis of the experimental results, including fatigue lives, strain distribution, temperature variation, stiffness degradation, and typical damage morphologies at different fatigue cycles, has been conducted by utilizing DIC, infrared thermography (IRT) and computed tomography (CT). It is observed that the superimposed torsional fatigue load results in a rapid reduction in fatigue lives of plain weave composites, accompanied by more significant residual strain, energy dissipation, temperature rise and stiffness degradation. Particularly, the superimposed torsional fatigue loads mainly promote matrix cracking and debonding around the fiber/matrix interfaces, which then accelerates the damage initiations and accumulations of fiber yarns, ultimately leading to a rapid reduction in TTF fatigue lives. This study can provide valuable references for the design and safe application of plain weave composites under TTF loading. [ABSTRACT FROM AUTHOR]

• A new expression to predict the upper limit of constant strain rate. • Negative correlation between strength and strain rate of hybrid composites. • The validity of the nonlinear constitutive model to dynamic property. • The effect of hybridization and strain rates on fracture modes. Based on the analysis of stress wave propagation at both ends of the specimen, a formula for the upper limit of the constant strain rate is derived. The upper limit of constant strain rate is applicable to all the ratios of wave impedance, providing a broader applicability. The in-plane dynamic compressive behavior was obtained for 2D plain weave carbon/aramid hybrid composites at strain rates ranging from 195 to 790 s−1. The results validate the prediction of the upper limit of the constant strain rate. The strength exhibited sensitive to strain rate. A nonlinear constitutive model described the dynamic constitutive relationship effectively under different strain rates. The distribution of delamination failure significantly influenced the final failure shape of the specimens. Microscopic observations indicated that carbon fiber yarns and aramid fiber yarns exhibited different fracture modes. [ABSTRACT FROM AUTHOR]