An anisotropic visco-hyperelastic constitutive model for rate-temperature-dependent deformation during one-step hot stamping forming simulation of unidirectional (UD) CF/PEEK prepregs is presented. This constitutive model is based on strain energy decomposition and a multiplicative decomposition of the deformation gradient. Two simple Maxwell models are used to characterize the viscoelastic behavior of the melted PEEK matrix and longitudinal shear deformation, respectively, and a shear invariant of $I_{\mathrm{\text{sh}}}=I_5-I_4$ is proposed to calculate the shear deformation. Moreover, the fiber stretching deformation is modeled by an anisotropic hyperelastic model. To obtain the model parameters, tensile tests at different strain rates and temperatures above the melt temperature of PEEK are performed on $0^{\circ }$, $10^{\circ }$, and $90^{\circ }$ CF/PEEK prepreg specimens, respectively. In parallel, the [0]₈ and [45]₈ curved beam specimens are experimentally fabricated to validate the constitutive model. The VUMAT subroutine is developed according to the proposed constitutive model and applied for a $10-40^{\circ }$ off-axis tensile simulation and hot-stamping forming simulation of CF/PEEK prepregs. The experimental and simulation results show that the materials flow, distribution of strain and stress, forming defects (wrinkles and overlap) of CF/PEEK curved beam can be captured by the proposed model.

提出了一种在单向 (UD) CF/PEEK 预浸料的一步热冲压成型模拟过程中速率与温度相关变形的各向异性粘超弹性本构模型。该本构模型基于应变能分解和变形梯度的乘法分解。两个简单的麦克斯韦模型分别用于表征熔融 PEEK 基体的粘弹性行为和纵向剪切变形，剪切不变量为${我}_{\mathrm{\text{嘘}}}={我}_5-{我}_4$建议计算剪切变形。此外，纤维拉伸变形通过各向异性超弹性模型进行建模。为了获得模型参数，在不同应变速率和高于 PEEK 熔化温度的温度下进行拉伸测试$0^{\circ }$,$10^{\circ }$， 和$90^{\circ }$分别为 CF/PEEK 预浸料样品。同时，通过实验制作了 [0] ₈和 [45] ₈曲梁样本以验证本构模型。VUMAT 子程序是根据所提出的本构模型开发的，并应用于$10-40^{\circ }$CF/PEEK 预浸料的离轴拉伸模拟和热冲压成型模拟。实验和仿真结果表明，该模型可以捕获CF/PEEK曲梁的材料流动、应变和应力分布、成形缺陷（皱纹和重叠）。