基于机器学习的宽谱随机疲劳损伤计算方法

A machine learning-based method for wide-band random fatigue

  • 摘要: 【目的】本文针对宽谱随机疲劳载荷作用下传统频域疲劳分析方法计算精度不足的问题,提出一种基于机器学习的频域宽谱随机疲劳损伤计算方法。【方法】首先,基于11种参数化应力谱形,构建覆盖不同谱矩参数、谱宽参数与雨流计数疲劳损伤的数据集,用于神经网络模型的训练、隐藏层结构优化与性能评估;其次,使用独立生成的新应力谱开展数值仿真验证,系统评估模型的预测精度与泛化能力;随后,采用SHAP (SHapley Additive exPlanations) 分析解释模型的内部学习机制;最后,通过极端谱宽工况与实际工程仿真数据,检验模型在极端谱宽条件与真实工程场景下的适用性。【结果】各验证工况下的结果表明,本文方法的预测精度整体优于传统频域方法,多数工况的最大相对误差控制在5%以内,平均绝对百分比误差低于1%,且单次预测平均耗时约4.5 ms,能够在保证疲劳损伤预测精度的同时具备良好的计算效率。通过SHAP可解释性分析表明,四阶谱矩是影响模型预测的主要特征变量。【结论】本文构建的神经网络模型能够有效学习谱矩参数与疲劳损伤之间的复杂非线性映射关系,突破了传统频域方法受限于解析结构难以充分表征复杂谱矩特征的局限,实现了宽谱疲劳损伤的高效率、高精度预测。

     

    Abstract: Objectives To address the insufficient accuracy of conventional frequency-domain fatigue analysis methods under wide-band random fatigue loading, a machine learning-based method for frequency-domain calculation of wide-band random fatigue damages is proposed. Methods First, a dataset relating a wide range of spectral moment parameters and spectral width parameters to the corresponding rainflow counting fatigue damage is constructed based on 11 types of parameterized stress spectra for training, hidden layer structure optimization and performance evaluation using a neural network based machine-learning model. Secondly, numerical simulation validation is conducted using independently generated set of new stress spectra to systematically assess the prediction accuracy and generalization ability of the model. Thirdly, SHAP (SHapley Additive exPlanations) analysis is conducted to interpret the internal learning mechanism of the model. Finally, the applicability of the model under extreme spectral width conditions and real engineering scenarios is examined through extreme spectral width cases and actual engineering simulation data. Results The results under all validation cases demonstrate that the proposed method generally outperforms traditional frequency-domain methods in prediction accuracy. In most cases, the maximum relative error is maintained within 5%, with the mean absolute percentage error below 1%; the average computational time per prediction is approximately 4.5 ms, indicating high computational efficiency while ensuring reliable fatigue damage prediction. SHAP-based interpretability analysis reveals that the fourth-order spectral moment serves as the dominant feature driving the model predictions. Conclusions The proposed ANN model effectively captures the complex nonlinear mapping relationship between spectral moment and fatigue damage, overcoming the limitation of traditional frequency-domain methods that are constrained by analytical formulations and cannot adequately characterize complex spectral moment features. Consequently, the proposed method achieves high-efficiency and high-precision prediction of broadband random fatigue damage.

     

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