发表机构
TU Dortmund University（多特蒙德工业大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出基于耐久性表面概念的疲劳连续损伤框架，以能量释放率为驱动力，通过微形态梯度增强正则化，纳入各向异性损伤演化等，可模拟高周疲劳损伤，适用于多种实际场景。
AI 中文摘要
本文基于耐久性表面概念提出了一种新的疲劳连续损伤框架，并将能量释放率用作驱动力。损伤演化由热力学驱动力到耐久性表面的距离控制。与经典破坏面不同，这使得损伤即使在等幅加载下也能在多个循环中累积。耐久性表面直接决定了材料的物理耐久极限。为获得与网格无关的结果，该公式通过微形态梯度增强进行正则化。纳入各向异性损伤演化和微裂纹闭合-重新开启效应，将框架扩展到多轴疲劳和与加载路径相关的退化。所选的原型损伤演化满足三个要求：合理的物理原理、计算稳健性和校准灵活性。该模型已成功校准到素混凝土的单调响应和低合金钢的高周疲劳行为。数值示例涵盖L形混凝土试件的单调破坏、循环加载下的应力-寿命行为以及轴向-扭转组合疲劳。这些案例展示了所提出的公式如何应用于从标准准脆性断裂基准到经典疲劳表征和复杂多轴损伤演化的实际场景。示例表明，该公式捕捉了多个循环中的渐进退化，并再现了特征应力-寿命行为。各向异性退化的影响在多轴加载条件下接近破坏阶段时尤为显著。总体而言，该方法为模拟高周疲劳驱动的损伤提供了一个热力学一致、梯度增强且计算稳健的框架。
英文摘要
This work proposes a novel continuum damage framework for fatigue based on the endurance-surface concept and uses the energy-release rate as the driving force. Damage evolution is governed by the distance of the thermodynamic driving force from the endurance surface. In contrast to classic failure surfaces, this allows damage to accumulate over many cycles even under constant-amplitude loading. The endurance surface therefore directly relates to the physical endurance limit of the material. To obtain mesh-objective results, the formulation is regularized by a micromorphic gradient enhancement. The incorporation of anisotropic damage evolution and the microcrack-closure-reopening effect extends the framework to multiaxial fatigue and loading-path-dependent degradation. The chosen prototype damage evolution fulfills three requirements: reasonable physics, computational robustness, and calibration flexibility. The model is successfully calibrated to both the monotonic response of plain concrete and to the high-cycle fatigue behavior of low-alloy steel. The numerical examples cover monotonic failure of an L-shaped concrete specimen, stress-life behavior under cyclic loading, and combined axial-torsional fatigue. These cases demonstrate how the proposed formulation applies to practical scenarios ranging from standard quasi-brittle fracture benchmarks to classical fatigue characterization and complex multiaxial damage evolution. The examples demonstrate that the formulation captures progressive degradation over many cycles and reproduces characteristic stress-life behavior. The influence of anisotropic degradation becomes especially relevant under multiaxial loading conditions during the near-failure phase. Overall, the approach provides a thermodynamically consistent, gradient-enhanced, and computationally robust framework for simulating fatigue-driven damage in the high-cycle regime.
Comments19 pages, 7 figures
