Multi-fidelity surrogate modeling of fatigue cracks integrating the effects of parameter randomness

Penetrating fatigue cracks critically compromise the structural integrity and operational reliability of mechanical components. Predicting three-dimensional fatigue crack propagation involves complex multi-parameter interactions and computationally intensive simulations, posing significant challenges for efficient life assessment. To bridge this gap, this work developed a probabilistic multi-fidelity surrogate model that integrates experimental characterization and finite element analysis. The framework employs a D-vine copula model to quantify uncertainties and dependencies in key parameters, while an adaptive stochastic configuration network ensemble surrogate emulates crack-growth responses with high computational efficiency. Validated through ASTM-compliant fatigue tests on 25CrNiMo alloy specimens. Results demonstrate that the proposed methodology enables efficient, high-accuracy fatigue life evaluation for engineering structures operating under uncertainty, providing a robust tool for reliability-driven design and maintenance.

贯穿性疲劳裂纹会严重削弱机械构件的结构完整性与运行可靠性。三维疲劳裂纹扩展预测涉及复杂的多参数交互作用与计算密集型模拟，给高效寿命评估带来了显著挑战。为填补这一研究空白，本研究开发了一种融合实验表征与有限元分析的概率多保真度替代模型。该框架采用D藤Copula（D-vine copula）模型量化关键参数的不确定性与依赖关系，并通过自适应随机配置网络集成替代模型，以极高的计算效率模拟裂纹扩展响应。本模型通过针对25CrNiMo合金试样的ASTM标准疲劳试验完成验证。结果表明，所提方法能够为存在不确定性的工程结构实现高效且高精度的疲劳寿命评估，为可靠性驱动的设计与维护提供了可靠工具。