基于人工智能的GH4065A高温合金涡轮盘拉削工艺参数预测模型研究

Research on an AI-based prediction model for the broaching process parameters of GH4065A superalloy turbine disks

  • 摘要: 航空发动机GH4065A高温合金涡轮盘榫槽加工时,切削力大、加工易变形,高速拉削过程中高去除率与低切削力难以同时满足,在其拉削工艺参数优化与预测时,面临小样本、多目标、强非线性优化难题。文章基于有限元仿真及实际拉削实验,对不同拉刀尺寸及拉削参数下的高温合金GH4065A拉削过程中的拉削力、最大等效应力、去除率等进行了采集,构建了“SMOGN-XGBoost-SHAP-NSGA-II”一体化的人工智能方法。首先基于有限元仿真获得29组原始拉削数据,并采用SMOGN算法将样本扩展至145组,显著缓解了数据稀疏导致的过拟合风险;继而利用贝叶斯优化调参的XGBoost建立切削力、切削温度、等效应力和材料去除率的高精度代理模型,测试集决定系数R2均大于0.90;通过沙普利加性解释(Shapley additive explanations, SHAP)揭示拉削线速度为各响应的首要影响因子,并量化参数间非线性耦合效应;最后以NSGA-II开展三目标优化,在150代内收敛,获得分布均匀的Pareto前沿,并给出工程可实施的折中解,同时对比了真实实验结果与模型预测结果。验证实验表明,推荐参数下预测-仿真实测误差小于5%,而真实实验结果与模型预测值误差也小于5%,实现了小样本条件下“高精度—可解释—多目标”闭环优化,为难加工材料高效精密拉削提供了可移植的决策框架。

     

    Abstract: During the broaching of tenon grooves in GH4065A high-temperature alloy turbine disks for aero-engines, challenges such as large cutting forces, high susceptibility to machining deformation, and the difficulty in simultaneously achieving high material removal rate and low cutting force in high-speed broaching are encountered. When optimizing and predicting broaching process parameters, problems including small sample size, multi-objective requirements, and strong nonlinearity need to be addressed. Based on finite element simulation and actual broaching experiments, this study collected data (e.g., broaching force, maximum equivalent stress, and material removal rate) during the broaching of GH4065A high-temperature alloy under different broach dimensions and broaching parameters, and constructed an integrated artificial intelligence method named "SMOGN-XGBoost-SHAP-NSGA-II". Firstly, 29 groups of original broaching data were obtained via finite element simulation, and the SMOGN algorithm was applied to expand the sample size to 145 groups, which significantly alleviated the overfitting risk caused by sparse data; subsequently, an XGBoost model with hyperparameters tuned by Bayesian optimization was used to establish high-precision surrogate models for cutting force, cutting temperature, equivalent stress, and material removal rate, with the coefficient of determination (R2) of all models on the test set exceeding 0.90. Through SHAP (Shapley additive explanations) interpretation, broaching linear speed was identified as the primary influencing factor for each response, and the nonlinear coupling effects between parameters were quantified. Finally, the NSGA-II algorithm was employed for three-objective optimization, which achieved convergence within 150 generations, obtained a uniformly distributed Pareto front, and provided engineering-feasible compromise solutions, while comparisons were conducted between real experimental results and model prediction results. Verification experiments show that the error between predicted and simulated measured values under the recommended parameters is less than 5%, and the error between real experimental results and model predicted values is also less than 5%, which realizes the closed-loop optimization of "high precision-interpretability-multi-objective" under small sample conditions and provides a portable decision-making framework for efficient and precise broaching of difficult-to-machine materials.

     

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