基于NRS-TPE-LGBM的合金690应力腐蚀裂纹扩展速率预测

    Prediction of Stress Corrosion Crack Propagation Rate for Alloy 690 Based on NRS-TPE-LGBM

    • 摘要: 合金690在工作时受温度、气压、输送介质等因素的影响,合金管道的应力腐蚀预测容易出现异方差性和非稳定性的问题,难以精确预测合金690管道的应力腐蚀速率,为了提高高温环境下合金690应力腐蚀裂纹扩展速率的预测精度,将邻域粗糙集(NRS)、贝叶斯优化(TPE)和轻量级梯度提升学习机(LGBM)相结合,建立基于NRS-TPE-LGBM的合金690应力腐蚀裂纹扩展速率预测模型。利用NRS的属性约简降低数据维度,提高模型的运行效率,然后利用TPE对超参数寻优,使LGBM的梯度提升能力达到最优,同时引入相对误差评价指标,建立数据集与预测集进行对比。结果表明:基于NRS-TPE-LGBM模型预测精度相较于未优化的LGBM模型和经随机搜索算法优化的LGBM模型分别提升4.81%和2.52%,验证了模型的准确性,为合金管道的实际工程维修和更换提供较为精准的判断依据。

       

      Abstract: Alloy 690 is influenced by factors like temperature, atmospheric pressure, and the transport medium during operation. Stress corrosion in alloy pipelines often exhibits heteroscedasticity and instability, complicating the accurate prediction of the stress corrosion rate for alloy 690 pipelines. In order to improve the prediction accuracy of stress corrosion crack growth rate of Alloy 690 under high temperature environment, the NRS-TPE-LGBM prediction model was established by combining neighborhood rough set (NRS), Bayesian optimization(TPE) and lightweight gradient boosting learning machine (LGBM). The attributes of NRS were used to reduce the dimension of data and improve the operation efficiency of the model. Then, TPE was used to optimize the hyperparameters, so that the gradient boosting capability of LGBM can reach the optimal, and the relative error evaluation index was introduced to establish the comparison between the data set and the prediction set. The results show that compared with the unoptimized LGBM model and the LGBM model optimized by random search algorithm, the prediction accuracy of NRS-TPE-LGBM model is improved by 4.81% and 2.52%, respectively, which verifies the accuracy of the model and provides a more accurate judgment basis for the actual engineering maintenance and replacement of alloy pipelines.

       

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