Uniaxial and multiaxial ratcheting tests of zirconium cladding tubes with constant internal pressure and cyclic axial loading were conducted at 648 K, aiming to investigate the influences of axial mean stress, stress amplitude, and inner pressure. Anomalous ratcheting behaviors were observed, including negative axial ratcheting strain accumulation under symmetric uniaxial cyclic loading conditions and significant changes in axial ratcheting strain direction under certain multiaxial loading conditions. A general formulation of kinematic hardening models was proposed to decouple asymmetry and anisotropy of the kinematic hardening rule from that of the initial yielding. On this basis, a phenomenological model incorporating the effects of the $\left\{10\overline{1}2\right\}$$\left\{10\overline{1}2\right\}$ twinning-detwinning mechanism on cyclic plasticity was formulated to simulate the observed anomalous ratcheting behaviors. The predictions of the proposed model show acceptable agreement with the test results.

中文翻译：

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648 K 下锆合金管在循环轴向载荷和内压联合作用下异常多轴棘轮行为的运动学硬化本构模型


在 648 K 下对具有恒定内压和循环轴向载荷的锆包层管进行了单轴和多轴棘轮试验，旨在研究轴向平均应力、应力幅值和内压的影响。观察到异常棘轮行为，包括对称单轴循环载荷条件下的负轴向棘轮应变累积和某些多轴载荷条件下轴向棘轮应变方向的显着变化。提出了运动学硬化模型的一般公式，以将运动学硬化规则的不对称性和各向异性与初始屈服的不对称性和各向异性解耦。在此基础上，制定了一个现象学模型，该模型结合了 $\left\{10\overline{1}2\right\}$ 孪生-解孪生机制对循环塑性的影响，以模拟观察到的异常棘轮行为。所提出模型的预测与测试结果显示出可接受的一致性。