An analytical model is proposed to investigate the linear and nonlinear mechanical response of reinforced thermoplastic pipes (RTPs) under axial tension, in which the existing homogenization method, failure criteria and material degradation models are combined to predict the CDM behavior in an iterative and cyclic way. To obtain damage sequences, the homogenization method is modified by a stress correction factor to consider the effect of cross-sectional curvature. Once corrected stresses of homogenous layers satisfy von Mises criterion, Ramberg-Osgood curve is used to update elastic constants of isotropic materials. For composite laminates, a nonlinear stiffness degradation model is adopted to update the stiffness matrix if Hashin-Yeh failure criterion is satisfied. Quasi-static uniaxial tension tests were conducted on two RTP specimens to verify the proposed model. Besides, numerical simulation by calling a VUMAT subroutine were performed to observe the stress field in 3D composites. The proposed model was found to give accurate prediction on stiffness characteristics and stress field, and have functions including identifying damage location, predicting failure mode, and analyzing damage propagation. Furthermore, the effects of winding angles are studied, which showed that dominant failure mode would change from tensile fiber to tensile matrix as winding angles rise.

提出了一个分析模型来研究增强热塑性管（RTP）在轴向拉力下的线性和非线性力学响应，该模型结合了现有的均质化方法，破坏准则和材料降解模型，以迭代和循环的方式预测CDM行为。 。为了获得损伤序列，均质化方法通过应力校正因子进行修改，以考虑截面曲率的影响。一旦均质层的校正应力满足von Mises准则，就可以使用Ramberg-Osgood曲线更新各向同性材料的弹性常数。对于复合材料层合板，如果满足Hashin-Yeh破坏准则，则采用非线性刚度退化模型更新刚度矩阵。对两个RTP标本进行了准静态单轴拉伸试验，以验证所提出的模型。此外，通过调用VUMAT子例程进行了数值模拟，以观察3D复合材料中的应力场。发现该模型可以对刚度特性和应力场提供准确的预测，并具有识别损坏位置，预测破坏模式和分析损坏传播的功能。此外，研究了缠绕角的影响，结果表明，随着缠绕角的增加，主导失效模式将从拉伸纤维变为拉伸基体。并具有识别损坏位置，预测故障模式和分析损坏传播的功能。此外，研究了缠绕角的影响，结果表明，随着缠绕角的增加，主导失效模式将从拉伸纤维变为拉伸基体。并具有识别损坏位置，预测故障模式和分析损坏传播的功能。此外，研究了缠绕角的影响，结果表明，随着缠绕角的增加，主导失效模式将从拉伸纤维变为拉伸基体。