Abstract An elastic-viscoplastic constitutive material model is developed for the representation of the creep response of a 10%Cr steel under cyclic loading conditions. It has been shown that the model is able to describe primary creep regeneration (PCR), i.e. the incidence of a period of high creep strain rate following a stress reversal. The developed model is a variant of the well-known Chaboche viscoplastic constitutive model, and employs a bi-term power-law equation to represent the stress-regime dependence of the viscoplastic strain rate response. Back stress and drag stress are used to describe the kinematic and isotropic hardening/softening behaviour of the material, respectively. The evolutions of back stress and drag stress consider contributions from strain hardening, dynamic softening, static recovery and cyclic hardening/softening. The effectiveness of the developed model for describing the sensitivity of the PCR behaviour to different loading parameters (e.g. reverse-loading magnitude and duration) and to represent the effect of PCR activation on the overall strain accumulation behaviour of the material is discussed. Furthermore, the predictive capability of the model is demonstrated for describing the response of the material during two independent benchmark tests; a stress-varying creep and a low-cycle fatigue experiments.

中文翻译：

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10%Cr马氏体钢一次蠕变再生研究：统一本构模型

摘要 开发了一种弹粘塑性本构材料模型，用于表示 10% Cr 钢在循环载荷条件下的蠕变响应。已经表明，该模型能够描述初级蠕变再生（PCR），即应力反转后高蠕变应变率时期的发生。开发的模型是著名的 Chaboche 粘塑性本构模型的变体，并采用双项幂律方程来表示粘塑性应变速率响应的应力状态依赖性。背应力和拖曳应力分别用于描述材料的运动学和各向同性硬化/软化行为。背应力和拖曳应力的演变考虑了应变硬化、动态软化、静态恢复和循环硬化/软化的贡献。讨论了用于描述 PCR 行为对不同加载参数（例如反向加载幅度和持续时间）的敏感性以及表示 PCR 激活对材料的整体应变累积行为的影响的开发模型的有效性。此外，模型的预测能力被证明用于描述材料在两个独立基准测试期间的响应；应力变化蠕变和低周疲劳实验。在两个独立的基准测试期间，模型的预测能力被证明用于描述材料的响应；应力变化蠕变和低周疲劳实验。在两个独立的基准测试期间，模型的预测能力被证明用于描述材料的响应；应力变化蠕变和低周疲劳实验。